This is v8 of the compile-time stack validation patch set, based on the
tip/master branch.
The frame pointer macros are still called FRAME and ENDFRAME because I
don't think we converged on anything else yet. Otherwise I tried to
address all the other review comments from v7.
v7 can be found here:
https://lkml.kernel.org/r/[email protected]
For more information about the motivation behind this patch set, and
more details about what it does, please see the changelog in patch 3.
Patches 1-5 are the stackvalidate tool and some related macros.
Patches 6-21 are some proposed fixes for several of the warnings
reported by stackvalidate. They've been compile-tested and boot tested
in a VM, but I haven't attempted any meaningful testing for many of
them.
v8:
- add proposed fixes for warnings
- fix all memory leaks
- process ignores earlier and add more ignore checks
- always assume POPCNT alternative is enabled
- drop hweight inline asm fix
- drop __schedule() ignore patch
- change .Ltemp_\@ to .Lstackvalidate_ignore_\@ in asm macro
- fix CONFIG_* checks in asm macros
- add C versions of ignore macros and frame macros
- change ";" to "\n" in C macros
- add ifdef CONFIG_STACK_VALIDATION checks in C ignore macros
- use numbered label in C ignore macro
- add missing break in switch case statement in arch-x86.c
v7:
- sibling call support
- document proposed solution for inline asm() frame pointer issues
- say "kernel entry/exit" instead of "context switch"
- clarify the checking of switch statement jump tables
- discard __stackvalidate_ignore_* sections in linker script
- use .Ltemp_\@ to get a unique label instead of static 3-digit number
- change STACKVALIDATE_IGNORE_FUNC variable to a static
- move STACKVALIDATE_IGNORE_INSN to arch-specific .h file
v6:
- rename asmvalidate -> stackvalidate (again)
- gcc-generated object file support
- recursive branch state analysis
- external jump support
- fixup/exception table support
- jump label support
- switch statement jump table support
- added documentation
- detection of "noreturn" dead end functions
- added a Kbuild mechanism for skipping files and dirs
- moved frame pointer macros to arch/x86/include/asm/frame.h
- moved ignore macros to include/linux/stackvalidate.h
v5:
- stackvalidate -> asmvalidate
- frame pointers only required for non-leaf functions
- check for the use of the FP_SAVE/RESTORE macros instead of manually
analyzing code to detect frame pointer usage
- additional checks to ensure each function doesn't leave its boundaries
- make the macros simpler and more flexible
- support for analyzing ALTERNATIVE macros
- simplified the arch interfaces in scripts/asmvalidate/arch.h
- fixed some asmvalidate warnings
- rebased onto latest tip asm cleanups
- many more small changes
v4:
- Changed the default to CONFIG_STACK_VALIDATION=n, until all the asm
code can get cleaned up.
- Fixed a stackvalidate error path exit code issue found by Michal
Marek.
v3:
- Added a patch to make the push/pop CFI macros arch-independent, as
suggested by H. Peter Anvin
v2:
- Fixed memory leaks reported by Petr Mladek
Josh Poimboeuf (21):
x86/asm: Frame pointer macro cleanup
x86/asm: Add C versions of FRAME and ENDFRAME macros
x86/stackvalidate: Compile-time stack validation
x86/stackvalidate: Add file and directory ignores
x86/stackvalidate: Add ignore macros
x86/xen: Add stack frame dependency to hypercall inline asm calls
x86/paravirt: Add stack frame dependency to PVOP inline asm calls
x86/paravirt: Fix frame pointer usage in PV_CALLEE_SAVE_REGS_THUNK
x86/paravirt: Align paravirt thunk functions at 16-byte boundaries
x86/amd: Set ELF function type for vide()
x86/reboot: Add ljmp instructions to stackvalidate whitelist
x86/xen: Add xen_cpuid() and xen_setup_gdt() to stackvalidate
whitelists
x86/asm/crypto: Fix frame pointer usage in aesni-intel_asm.S
x86/asm/crypto: Move .Lbswap_mask data to .rodata section
x86/asm/crypto: Move jump_table to .rodata section
x86/asm/crypto: Fix frame pointer usage in clmul_ghash_mul/update()
x86/asm/entry: Fix frame pointer usage in thunk functions
x86/asm/acpi: Fix frame pointer usage in do_suspend_lowlevel()
x86/asm: Fix frame pointer usage in rwsem functions
x86/asm/efi: Fix frame pointer usage in efi_call()
x86/asm/power: Fix frame pointer usage in hibernate_asm_64.S
Documentation/stack-validation.txt | 193 ++++++
MAINTAINERS | 8 +
arch/Kconfig | 6 +
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 6 +-
arch/x86/boot/Makefile | 3 +-
arch/x86/boot/compressed/Makefile | 3 +-
arch/x86/crypto/aesni-intel_asm.S | 21 +
arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 8 +-
arch/x86/crypto/ghash-clmulni-intel_asm.S | 5 +
arch/x86/entry/thunk_64.S | 4 +
arch/x86/entry/vdso/Makefile | 5 +-
arch/x86/include/asm/frame.h | 51 +-
arch/x86/include/asm/paravirt.h | 10 +-
arch/x86/include/asm/paravirt_types.h | 18 +-
arch/x86/include/asm/stackvalidate.h | 45 ++
arch/x86/include/asm/xen/hypercall.h | 5 +-
arch/x86/kernel/acpi/wakeup_64.S | 3 +
arch/x86/kernel/cpu/amd.c | 5 +-
arch/x86/kernel/reboot.c | 7 +-
arch/x86/kernel/vmlinux.lds.S | 5 +-
arch/x86/lib/rwsem.S | 11 +-
arch/x86/platform/efi/efi_stub_64.S | 3 +
arch/x86/power/hibernate_asm_64.S | 7 +
arch/x86/purgatory/Makefile | 2 +
arch/x86/realmode/Makefile | 4 +-
arch/x86/realmode/rm/Makefile | 3 +-
arch/x86/xen/enlighten.c | 4 +-
drivers/firmware/efi/libstub/Makefile | 1 +
include/linux/stackvalidate.h | 28 +
lib/Kconfig.debug | 11 +
scripts/Makefile | 1 +
scripts/Makefile.build | 34 +-
scripts/stackvalidate/Makefile | 24 +
scripts/stackvalidate/arch-x86.c | 160 +++++
scripts/stackvalidate/arch.h | 44 ++
scripts/stackvalidate/elf.c | 427 ++++++++++++++
scripts/stackvalidate/elf.h | 92 +++
scripts/stackvalidate/list.h | 217 +++++++
scripts/stackvalidate/special.c | 197 +++++++
scripts/stackvalidate/special.h | 41 ++
scripts/stackvalidate/stackvalidate.c | 949 ++++++++++++++++++++++++++++++
42 files changed, 2624 insertions(+), 48 deletions(-)
create mode 100644 Documentation/stack-validation.txt
create mode 100644 arch/x86/include/asm/stackvalidate.h
create mode 100644 include/linux/stackvalidate.h
create mode 100644 scripts/stackvalidate/Makefile
create mode 100644 scripts/stackvalidate/arch-x86.c
create mode 100644 scripts/stackvalidate/arch.h
create mode 100644 scripts/stackvalidate/elf.c
create mode 100644 scripts/stackvalidate/elf.h
create mode 100644 scripts/stackvalidate/list.h
create mode 100644 scripts/stackvalidate/special.c
create mode 100644 scripts/stackvalidate/special.h
create mode 100644 scripts/stackvalidate/stackvalidate.c
--
2.1.0
The FRAME/ENDFRAME asm macros for setting up and restoring the frame
pointer aren't currently being used. However, they will be needed soon
to help asm functions to comply with stackvalidate.
Make the code more readable and improve the comments.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/frame.h | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h
index 793179c..a4ac454 100644
--- a/arch/x86/include/asm/frame.h
+++ b/arch/x86/include/asm/frame.h
@@ -1,23 +1,26 @@
+#ifndef _ASM_X86_FRAME_H
+#define _ASM_X86_FRAME_H
+
#ifdef __ASSEMBLY__
#include <asm/asm.h>
-/* The annotation hides the frame from the unwinder and makes it look
- like a ordinary ebp save/restore. This avoids some special cases for
- frame pointer later */
+/*
+ * These are stack frame creation macros. They should be used by every
+ * callable non-leaf asm function to make kernel stack traces more reliable.
+ */
+.macro FRAME
+#ifdef CONFIG_FRAME_POINTER
+ push %_ASM_BP
+ _ASM_MOV %_ASM_SP, %_ASM_BP
+#endif
+.endm
+
+.macro ENDFRAME
#ifdef CONFIG_FRAME_POINTER
- .macro FRAME
- __ASM_SIZE(push,) %__ASM_REG(bp)
- __ASM_SIZE(mov) %__ASM_REG(sp), %__ASM_REG(bp)
- .endm
- .macro ENDFRAME
- __ASM_SIZE(pop,) %__ASM_REG(bp)
- .endm
-#else
- .macro FRAME
- .endm
- .macro ENDFRAME
- .endm
+ pop %_ASM_BP
#endif
+.endm
#endif /* __ASSEMBLY__ */
+#endif /* _ASM_X86_FRAME_H */
--
2.1.0
Add C versions of the FRAME and ENDFRAME macros which can be used to
create a stack frame in inline assembly.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/frame.h | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h
index a4ac454..fa38ceb 100644
--- a/arch/x86/include/asm/frame.h
+++ b/arch/x86/include/asm/frame.h
@@ -1,10 +1,10 @@
#ifndef _ASM_X86_FRAME_H
#define _ASM_X86_FRAME_H
-#ifdef __ASSEMBLY__
-
#include <asm/asm.h>
+#ifdef __ASSEMBLY__
+
/*
* These are stack frame creation macros. They should be used by every
* callable non-leaf asm function to make kernel stack traces more reliable.
@@ -22,5 +22,21 @@
#endif
.endm
+#else /* !__ASSEMBLY__ */
+
+#ifdef CONFIG_FRAME_POINTER
+
+#define FRAME \
+ "push %" _ASM_BP "\n" \
+ _ASM_MOV "%" _ASM_SP ", %" _ASM_BP "\n"
+
+#define ENDFRAME "pop %" _ASM_BP "\n"
+
+#else /* !CONFIG_FRAME_POINTER */
+
+#define FRAME ""
+#define ENDFRAME ""
+
+#endif /* CONFIG_FRAME_POINTER */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_FRAME_H */
--
2.1.0
This adds a CONFIG_STACK_VALIDATION option which enables a host tool
named stackvalidate which runs at compile time. It analyzes every .o
file and ensures the validity of its stack metadata. It enforces a set
of rules on asm code and C inline assembly code so that stack traces can
be reliable.
Currently it checks frame pointer usage. I also plan to add DWARF CFI
validation for C .o files and CFI generation for asm .o files.
For each function, it recursively follows all possible code paths and
validates the correct frame pointer state at each instruction.
It also follows code paths involving special sections, like
.altinstructions, __jump_table, and __ex_table, which can add
alternative execution paths to a given instruction (or set of
instructions). Similarly, it knows how to follow switch statements, for
which gcc sometimes uses jump tables.
To achieve the validation, stackvalidate enforces the following rules:
1. Each callable function must be annotated as such with the ELF
function type. In asm code, this is typically done using the
ENTRY/ENDPROC macros. If stackvalidate finds a return instruction
outside of a function, it flags an error since that usually indicates
callable code which should be annotated accordingly.
2. Conversely, each section of code which is *not* callable should *not*
be annotated as an ELF function. The ENDPROC macro shouldn't be used
in this case.
3. Each callable function which calls another function must have the
correct frame pointer logic, if required by CONFIG_FRAME_POINTER or
the architecture's back chain rules. This can by done in asm code
with the FRAME/ENDFRAME macros.
4. Dynamic jumps and jumps to undefined symbols are only allowed if:
a) the jump is part of a switch statement; or
b) the jump matches sibling call semantics and the frame pointer has
the same value it had on function entry.
5. A callable function may not execute kernel entry/exit instructions.
The only code which needs such instructions is kernel entry code,
which shouldn't be in callable functions anyway.
It currently only supports x86_64. I tried to make the code generic so
that support for other architectures can hopefully be plugged in
relatively easily.
As a first step, CONFIG_STACK_VALIDATION is disabled by default, and all
reported non-compliances result in warnings. Once we get them all
cleaned up, we can change the default to CONFIG_STACK_VALIDATION=y and
change the warnings to errors to keep the stack metadata clean.
On my Lenovo T430s 4-core laptop, building the kernel with it enabled
adds about 3.6 seconds (14.4 seconds of total CPU). It hasn't been
optimized for performance yet, so there are probably some opportunities
for better build performance.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
Documentation/stack-validation.txt | 193 +++++++
MAINTAINERS | 8 +
arch/Kconfig | 6 +
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 6 +-
lib/Kconfig.debug | 11 +
scripts/Makefile | 1 +
scripts/Makefile.build | 34 +-
scripts/stackvalidate/Makefile | 24 +
scripts/stackvalidate/arch-x86.c | 160 ++++++
scripts/stackvalidate/arch.h | 44 ++
scripts/stackvalidate/elf.c | 427 +++++++++++++++
scripts/stackvalidate/elf.h | 92 ++++
scripts/stackvalidate/list.h | 217 ++++++++
scripts/stackvalidate/special.c | 197 +++++++
scripts/stackvalidate/special.h | 41 ++
scripts/stackvalidate/stackvalidate.c | 949 ++++++++++++++++++++++++++++++++++
17 files changed, 2406 insertions(+), 5 deletions(-)
create mode 100644 Documentation/stack-validation.txt
create mode 100644 scripts/stackvalidate/Makefile
create mode 100644 scripts/stackvalidate/arch-x86.c
create mode 100644 scripts/stackvalidate/arch.h
create mode 100644 scripts/stackvalidate/elf.c
create mode 100644 scripts/stackvalidate/elf.h
create mode 100644 scripts/stackvalidate/list.h
create mode 100644 scripts/stackvalidate/special.c
create mode 100644 scripts/stackvalidate/special.h
create mode 100644 scripts/stackvalidate/stackvalidate.c
diff --git a/Documentation/stack-validation.txt b/Documentation/stack-validation.txt
new file mode 100644
index 0000000..d08c3c2
--- /dev/null
+++ b/Documentation/stack-validation.txt
@@ -0,0 +1,193 @@
+Compile-time stack validation
+=============================
+
+
+Overview
+--------
+
+The CONFIG_STACK_VALIDATION option enables a host tool named
+stackvalidate which runs at compile time. It analyzes every .o file and
+ensures the validity of its stack metadata. It enforces a set of rules
+on asm code and C inline assembly code so that stack traces can be
+reliable.
+
+Currently it only checks frame pointer usage, but there are plans to add
+CFI validation for C files and CFI generation for asm files.
+
+For each function, it recursively follows all possible code paths and
+validates the correct frame pointer state at each instruction.
+
+It also follows code paths involving special sections, like
+.altinstructions, __jump_table, and __ex_table, which can add
+alternative execution paths to a given instruction (or set of
+instructions). Similarly, it knows how to follow switch statements, for
+which gcc sometimes uses jump tables.
+
+
+Rules
+-----
+
+To achieve the validation, stackvalidate enforces the following rules:
+
+1. Each callable function must be annotated as such with the ELF
+ function type. In asm code, this is typically done using the
+ ENTRY/ENDPROC macros. If stackvalidate finds a return instruction
+ outside of a function, it flags an error since that usually indicates
+ callable code which should be annotated accordingly.
+
+2. Conversely, each section of code which is *not* callable should *not*
+ be annotated as an ELF function. The ENDPROC macro shouldn't be used
+ in this case.
+
+3. Each callable function which calls another function must have the
+ correct frame pointer logic, if required by CONFIG_FRAME_POINTER or
+ the architecture's back chain rules. This can by done in asm code
+ with the FRAME/ENDFRAME macros.
+
+4. Dynamic jumps and jumps to undefined symbols are only allowed if:
+
+ a) the jump is part of a switch statement; or
+
+ b) the jump matches sibling call semantics and the frame pointer has
+ the same value it had on function entry.
+
+5. A callable function may not execute kernel entry/exit instructions.
+ The only code which needs such instructions is kernel entry code,
+ which shouldn't be be in callable functions anyway.
+
+
+Errors in .S files
+------------------
+
+If you're getting an error in a compiled .S file which you don't
+understand, first make sure that the affected code follows the above
+rules.
+
+Here are some examples of common problems and suggestions for how to fix
+them.
+
+
+1. stackvalidate: asm_file.o: func()+0x128: call without frame pointer save/setup
+
+ The func() function made a function call without first saving and/or
+ updating the frame pointer.
+
+ If func() is indeed a callable function, add proper frame pointer
+ logic using the FP_SAVE and FP_RESTORE macros. Otherwise, remove its
+ ELF function annotation by changing ENDPROC to END.
+
+ If you're getting this error in a .c file, see the "Errors in .c
+ files" section.
+
+
+2. stackvalidate: asm_file.o: .text+0x53: return instruction outside of a callable function
+
+ A return instruction was detected, but stackvalidate couldn't find a
+ way for a callable function to reach the instruction.
+
+ If the return instruction is inside (or reachable from) a callable
+ function, the function needs to be annotated with the ENTRY/ENDPROC
+ macros.
+
+ If you _really_ need a return instruction outside of a function, and
+ are 100% sure that it won't affect stack traces, you can tell
+ stackvalidate to ignore it. See the "Adding exceptions" section
+ below.
+
+
+3. stackvalidate: asm_file.o: func()+0x9: function has unreachable instruction
+
+ The instruction lives inside of a callable function, but there's no
+ possible control flow path from the beginning of the function to the
+ instruction.
+
+ If the instruction is actually needed, and it's actually in a
+ callable function, ensure that its function is properly annotated
+ with ENTRY/ENDPROC.
+
+ If it's not actually in a callable function (e.g. kernel entry code),
+ change ENDPROC to END.
+
+
+4. stackvalidate: asm_file.o: func(): can't find starting instruction
+ or
+ stackvalidate: asm_file.o: func()+0x11dd: can't decode instruction
+
+ Did you put data in a text section? If so, that can confuse
+ stackvalidate's instruction decoder. Move the data to a more
+ appropriate section like .data or .rodata.
+
+
+5. stackvalidate: asm_file.o: func()+0x6: kernel entry/exit from callable instruction
+
+ This is a kernel entry/exit instruction like sysenter or sysret.
+ Such instructions aren't allowed in a callable function, and are most
+ likely part of the kernel entry code.
+
+ If the instruction isn't actually in a callable function, change
+ ENDPROC to END.
+
+
+6. stackvalidate: asm_file.o: func()+0x26: sibling call from callable instruction with changed frame pointer
+
+ This is a dynamic jump or a jump to an undefined symbol.
+ Stackvalidate assumed it's a sibling call and detected that the frame
+ pointer wasn't first restored to its original state.
+
+ If it's not really a sibling call, you may need to move the
+ destination code to the local file.
+
+ If the instruction is not actually in a callable function (e.g.
+ kernel entry code), change ENDPROC to END.
+
+
+7. stackvalidate: asm_file: func()+0x5c: frame pointer state mismatch
+
+ The instruction's frame pointer state is inconsistent, depending on
+ which execution path was taken to reach the instruction.
+
+ Make sure the function pushes and sets up the frame pointer (for
+ x86_64, this means rbp) at the beginning of the function and pops it
+ at the end of the function. Also make sure that no other code in the
+ function touches the frame pointer.
+
+
+Errors in .c files
+------------------
+
+If you're getting a stackvalidate error in a compiled .c file, chances
+are the file uses an asm() statement which has a "call" instruction. An
+asm() statement with a call instruction must declare the use of the
+stack pointer in its output operand. For example, on x86_64:
+
+ register void *__sp asm("rsp");
+ asm volatile("call func" : "+r" (__sp));
+
+Otherwise the stack frame may not get created before the call.
+
+Another possible cause for errors in C code is if the Makefile removes
+-fno-omit-frame-pointer or adds -fomit-frame-pointer to the gcc options.
+
+Also see the above section for .S file errors for more information what
+the individual error messages mean.
+
+
+
+Adding exceptions
+-----------------
+
+If you _really_ need stackvalidate to ignore something, and are 100%
+sure that it won't affect kernel stack traces, you can tell
+stackvalidate to ignore it:
+
+- To skip validation of an instruction, use the
+ STACKVALIDATE_IGNORE_INSN macro immediately before the instruction.
+
+- To skip validation of a function, use the STACKVALIDATE_IGNORE_FUNC
+ macro.
+
+- To skip validation of a file, add "STACKVALIDATE_filename.o := n" to
+ the Makefile.
+
+- To skip validation of a directory, add "STACKVALIDATE := n" to the
+ Makefile.
diff --git a/MAINTAINERS b/MAINTAINERS
index 6a8f227..8758dda 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9675,6 +9675,14 @@ L: [email protected]
S: Supported
F: Documentation/stable_kernel_rules.txt
+STACK VALIDATION
+M: Josh Poimboeuf <[email protected]>
+S: Supported
+F: scripts/stackvalidate/
+F: include/linux/stackvalidate.h
+F: arch/x86/include/asm/stackvalidate.h
+F: Documentation/stack-validation.txt
+
STAGING SUBSYSTEM
M: Greg Kroah-Hartman <[email protected]>
T: git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
diff --git a/arch/Kconfig b/arch/Kconfig
index 87579b9..f5a2c24 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -519,6 +519,12 @@ config HAVE_COPY_THREAD_TLS
normal C parameter passing, rather than extracting the syscall
argument from pt_regs.
+config HAVE_STACK_VALIDATION
+ bool
+ help
+ Architecture supports the stackvalidate host tool, which adds
+ compile-time stack metadata validation.
+
#
# ABI hall of shame
#
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cbd2d62..da13197 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -151,6 +151,7 @@ config X86
select VIRT_TO_BUS
select X86_DEV_DMA_OPS if X86_64
select X86_FEATURE_NAMES if PROC_FS
+ select HAVE_STACK_VALIDATION if X86_64
config INSTRUCTION_DECODER
def_bool y
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 054ff96..3b33286 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -181,9 +181,13 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
KBUILD_CFLAGS += $(mflags-y)
KBUILD_AFLAGS += $(mflags-y)
-archscripts: scripts_basic
+archscripts: scripts_basic $(objtree)/arch/x86/lib/inat-tables.c
$(Q)$(MAKE) $(build)=arch/x86/tools relocs
+# this file is needed early by scripts/stackvalidate
+$(objtree)/arch/x86/lib/inat-tables.c:
+ $(Q)$(MAKE) $(build)=arch/x86/lib $@
+
###
# Syscall table generation
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e7b5b65..cd1f50d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -332,6 +332,17 @@ config FRAME_POINTER
larger and slower, but it gives very useful debugging information
in case of kernel bugs. (precise oopses/stacktraces/warnings)
+config STACK_VALIDATION
+ bool "Enable compile-time stack metadata validation"
+ depends on HAVE_STACK_VALIDATION
+ default n
+ help
+ Add compile-time checks to validate stack metadata, including frame
+ pointers and back chain pointers. This helps ensure that runtime
+ stack traces are more reliable.
+
+ For more information, see Documentation/stack-validation.txt.
+
config DEBUG_FORCE_WEAK_PER_CPU
bool "Force weak per-cpu definitions"
depends on DEBUG_KERNEL
diff --git a/scripts/Makefile b/scripts/Makefile
index 2016a64..c882a91 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -37,6 +37,7 @@ subdir-y += mod
subdir-$(CONFIG_SECURITY_SELINUX) += selinux
subdir-$(CONFIG_DTC) += dtc
subdir-$(CONFIG_GDB_SCRIPTS) += gdb
+subdir-$(CONFIG_STACK_VALIDATION) += stackvalidate
# Let clean descend into subdirs
subdir- += basic kconfig package
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 01df30a..a1270d3 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -241,9 +241,26 @@ cmd_record_mcount = \
fi;
endif
+ifdef CONFIG_STACK_VALIDATION
+
+stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
+
+ifndef CONFIG_FRAME_POINTER
+nofp = --no-frame-pointer
+endif
+
+# Set STACKVALIDATE_foo.o=n to skip stack validation for a file.
+# Set STACKVALIDATE=n to skip stack validation for a directory.
+cmd_stackvalidate = $(if $(patsubst n%,, \
+ $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
+ $(stackvalidate) $(nofp) "$(@)";)
+
+endif # CONFIG_STACK_VALIDATION
+
define rule_cc_o_c
$(call echo-cmd,checksrc) $(cmd_checksrc) \
$(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
+ $(cmd_stackvalidate) \
$(cmd_modversions) \
$(call echo-cmd,record_mcount) \
$(cmd_record_mcount) \
@@ -253,14 +270,23 @@ define rule_cc_o_c
mv -f $(dot-target).tmp $(dot-target).cmd
endef
+define rule_as_o_S
+ $(call echo-cmd,as_o_S) $(cmd_as_o_S); \
+ $(cmd_stackvalidate) \
+ scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,as_o_S)' > \
+ $(dot-target).tmp; \
+ rm -f $(depfile); \
+ mv -f $(dot-target).tmp $(dot-target).cmd
+endef
+
# Built-in and composite module parts
-$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
+$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(stackvalidate) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
# Single-part modules are special since we need to mark them in $(MODVERDIR)
-$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
+$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(stackvalidate) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
@{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
@@ -290,8 +316,8 @@ $(obj)/%.s: $(src)/%.S FORCE
quiet_cmd_as_o_S = AS $(quiet_modtag) $@
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
-$(obj)/%.o: $(src)/%.S FORCE
- $(call if_changed_dep,as_o_S)
+$(obj)/%.o: $(src)/%.S $(stackvalidate) FORCE
+ $(call if_changed_rule,as_o_S)
targets += $(real-objs-y) $(real-objs-m) $(lib-y)
targets += $(extra-y) $(MAKECMDGOALS) $(always)
diff --git a/scripts/stackvalidate/Makefile b/scripts/stackvalidate/Makefile
new file mode 100644
index 0000000..468c075
--- /dev/null
+++ b/scripts/stackvalidate/Makefile
@@ -0,0 +1,24 @@
+hostprogs-y := stackvalidate
+always := $(hostprogs-y)
+
+stackvalidate-objs := stackvalidate.o elf.o special.o
+
+HOSTCFLAGS += -Werror
+HOSTLOADLIBES_stackvalidate := -lelf
+
+ifdef CONFIG_X86
+
+stackvalidate-objs += arch-x86.o
+
+HOSTCFLAGS_arch-x86.o := -I$(objtree)/arch/x86/lib/ \
+ -I$(srctree)/arch/x86/include/ \
+ -I$(srctree)/arch/x86/lib/
+
+$(obj)/arch-x86.o: $(srctree)/arch/x86/lib/insn.c \
+ $(srctree)/arch/x86/lib/inat.c \
+ $(srctree)/arch/x86/include/asm/inat_types.h \
+ $(srctree)/arch/x86/include/asm/inat.h \
+ $(srctree)/arch/x86/include/asm/insn.h \
+ $(objtree)/arch/x86/lib/inat-tables.c
+
+endif
diff --git a/scripts/stackvalidate/arch-x86.c b/scripts/stackvalidate/arch-x86.c
new file mode 100644
index 0000000..edc43a8
--- /dev/null
+++ b/scripts/stackvalidate/arch-x86.c
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+
+#define unlikely(cond) (cond)
+#include <asm/insn.h>
+#include <inat.c>
+#include <insn.c>
+#include <stdlib.h>
+
+#include "elf.h"
+#include "arch.h"
+
+static int is_x86_64(struct elf *elf)
+{
+ switch (elf->ehdr.e_machine) {
+ case EM_X86_64:
+ return 1;
+ case EM_386:
+ return 0;
+ default:
+ WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
+ return -1;
+ }
+}
+
+int arch_decode_instruction(struct elf *elf, struct section *sec,
+ unsigned long offset, unsigned int maxlen,
+ unsigned int *len, unsigned char *type,
+ unsigned long *immediate)
+{
+ struct insn insn;
+ int x86_64;
+ unsigned char op1, op2, ext;
+
+ x86_64 = is_x86_64(elf);
+ if (x86_64 == -1)
+ return -1;
+
+ insn_init(&insn, (void *)(sec->data + offset), maxlen, x86_64);
+ insn_get_length(&insn);
+ insn_get_opcode(&insn);
+ insn_get_modrm(&insn);
+ insn_get_immediate(&insn);
+
+ if (!insn.opcode.got || !insn.modrm.got || !insn.immediate.got) {
+ WARN("%s: can't decode instruction",
+ offstr(sec, offset));
+ return -1;
+ }
+
+ *len = insn.length;
+ *type = INSN_OTHER;
+
+ if (insn.vex_prefix.nbytes)
+ return 0;
+
+ op1 = insn.opcode.bytes[0];
+ op2 = insn.opcode.bytes[1];
+
+ switch (op1) {
+ case 0x55:
+ if (!insn.rex_prefix.nbytes)
+ /* push rbp */
+ *type = INSN_FP_SAVE;
+ break;
+
+ case 0x5d:
+ if (!insn.rex_prefix.nbytes)
+ /* pop rbp */
+ *type = INSN_FP_RESTORE;
+ break;
+
+ case 0x70 ... 0x7f:
+ *type = INSN_JUMP_CONDITIONAL;
+ break;
+
+ case 0x89:
+ if (insn.rex_prefix.nbytes == 1 &&
+ insn.rex_prefix.bytes[0] == 0x48 &&
+ insn.modrm.nbytes && insn.modrm.bytes[0] == 0xe5)
+ /* mov rsp, rbp */
+ *type = INSN_FP_SETUP;
+ break;
+
+ case 0x90:
+ *type = INSN_NOP;
+ break;
+
+ case 0x0f:
+ if (op2 >= 0x80 && op2 <= 0x8f)
+ *type = INSN_JUMP_CONDITIONAL;
+ else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
+ op2 == 0x35)
+ /* sysenter, sysret */
+ *type = INSN_CONTEXT_SWITCH;
+ else if (op2 == 0x0b || op2 == 0xb9)
+ /* ud2 */
+ *type = INSN_BUG;
+ else if (op2 == 0x0d || op2 == 0x1f)
+ /* nopl/nopw */
+ *type = INSN_NOP;
+ break;
+
+ case 0xc9: /* leave */
+ *type = INSN_FP_RESTORE;
+ break;
+
+ case 0xe3: /* jecxz/jrcxz */
+ *type = INSN_JUMP_CONDITIONAL;
+ break;
+
+ case 0xe9:
+ case 0xeb:
+ *type = INSN_JUMP_UNCONDITIONAL;
+ break;
+
+ case 0xc2:
+ case 0xc3:
+ *type = INSN_RETURN;
+ break;
+
+ case 0xc5: /* iret */
+ case 0xca: /* retf */
+ case 0xcb: /* retf */
+ *type = INSN_CONTEXT_SWITCH;
+ break;
+
+ case 0xe8:
+ *type = INSN_CALL;
+ break;
+
+ case 0xff:
+ ext = X86_MODRM_REG(insn.modrm.bytes[0]);
+ if (ext == 2 || ext == 3)
+ *type = INSN_CALL_DYNAMIC;
+ else if (ext == 4 || ext == 5)
+ *type = INSN_JUMP_DYNAMIC;
+ break;
+ }
+
+ *immediate = insn.immediate.nbytes ? insn.immediate.value : 0;
+
+ return 0;
+}
diff --git a/scripts/stackvalidate/arch.h b/scripts/stackvalidate/arch.h
new file mode 100644
index 0000000..f7350fc
--- /dev/null
+++ b/scripts/stackvalidate/arch.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ARCH_H
+#define _ARCH_H
+
+#include <stdbool.h>
+#include "elf.h"
+
+#define INSN_FP_SAVE 1
+#define INSN_FP_SETUP 2
+#define INSN_FP_RESTORE 3
+#define INSN_JUMP_CONDITIONAL 4
+#define INSN_JUMP_UNCONDITIONAL 5
+#define INSN_JUMP_DYNAMIC 6
+#define INSN_CALL 7
+#define INSN_CALL_DYNAMIC 8
+#define INSN_RETURN 9
+#define INSN_CONTEXT_SWITCH 10
+#define INSN_BUG 11
+#define INSN_NOP 12
+#define INSN_OTHER 13
+#define INSN_LAST INSN_OTHER
+
+int arch_decode_instruction(struct elf *elf, struct section *sec,
+ unsigned long offset, unsigned int maxlen,
+ unsigned int *len, unsigned char *type,
+ unsigned long *displacement);
+
+#endif /* _ARCH_H */
diff --git a/scripts/stackvalidate/elf.c b/scripts/stackvalidate/elf.c
new file mode 100644
index 0000000..29c3f29
--- /dev/null
+++ b/scripts/stackvalidate/elf.c
@@ -0,0 +1,427 @@
+/*
+ * elf.c - ELF access library
+ *
+ * Adapted from kpatch (https://github.com/dynup/kpatch):
+ * Copyright (C) 2013-2015 Josh Poimboeuf <[email protected]>
+ * Copyright (C) 2014 Seth Jennings <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "elf.h"
+
+char *offstr(struct section *sec, unsigned long offset)
+{
+ struct symbol *func;
+ char *name, *str;
+ unsigned long name_off;
+
+ func = find_containing_func(sec, offset);
+ if (func) {
+ name = func->name;
+ name_off = offset - func->offset;
+ } else {
+ name = sec->name;
+ name_off = offset;
+ }
+
+ str = malloc(strlen(name) + 20);
+
+ if (func)
+ sprintf(str, "%s()+0x%lx", name, name_off);
+ else
+ sprintf(str, "%s+0x%lx", name, name_off);
+
+ return str;
+}
+
+struct section *find_section_by_name(struct elf *elf, const char *name)
+{
+ struct section *sec;
+
+ list_for_each_entry(sec, &elf->sections, list)
+ if (!strcmp(sec->name, name))
+ return sec;
+
+ return NULL;
+}
+
+static struct section *find_section_by_index(struct elf *elf,
+ unsigned int index)
+{
+ struct section *sec;
+
+ list_for_each_entry(sec, &elf->sections, list)
+ if (sec->index == index)
+ return sec;
+
+ return NULL;
+}
+
+static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int index)
+{
+ struct section *sec;
+ struct symbol *sym;
+
+ list_for_each_entry(sec, &elf->sections, list)
+ list_for_each_entry(sym, &sec->symbols, list)
+ if (sym->index == index)
+ return sym;
+
+ return NULL;
+}
+
+struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
+{
+ struct symbol *sym;
+
+ list_for_each_entry(sym, &sec->symbols, list)
+ if (sym->type != STT_SECTION &&
+ sym->offset == offset)
+ return sym;
+
+ return NULL;
+}
+
+struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
+ unsigned int len)
+{
+ struct rela *rela;
+
+ if (!sec->rela)
+ return NULL;
+
+ list_for_each_entry(rela, &sec->rela->relas, list)
+ if (rela->offset >= offset && rela->offset < offset + len)
+ return rela;
+
+ return NULL;
+}
+
+struct rela *find_rela_by_dest(struct section *sec, unsigned long offset)
+{
+ return find_rela_by_dest_range(sec, offset, 1);
+}
+
+struct symbol *find_containing_func(struct section *sec, unsigned long offset)
+{
+ struct symbol *func;
+
+ list_for_each_entry(func, &sec->symbols, list)
+ if (func->type == STT_FUNC && offset >= func->offset &&
+ offset < func->offset + func->len)
+ return func;
+
+ return NULL;
+}
+
+static int read_sections(struct elf *elf)
+{
+ Elf_Scn *s = NULL;
+ struct section *sec;
+ size_t shstrndx, sections_nr;
+ int i;
+
+ if (elf_getshdrnum(elf->elf, §ions_nr)) {
+ perror("elf_getshdrnum");
+ return -1;
+ }
+
+ if (elf_getshdrstrndx(elf->elf, &shstrndx)) {
+ perror("elf_getshdrstrndx");
+ return -1;
+ }
+
+ for (i = 0; i < sections_nr; i++) {
+ sec = malloc(sizeof(*sec));
+ if (!sec) {
+ perror("malloc");
+ return -1;
+ }
+ memset(sec, 0, sizeof(*sec));
+
+ INIT_LIST_HEAD(&sec->symbols);
+ INIT_LIST_HEAD(&sec->relas);
+
+ list_add_tail(&sec->list, &elf->sections);
+
+ s = elf_getscn(elf->elf, i);
+ if (!s) {
+ perror("elf_getscn");
+ return -1;
+ }
+
+ sec->index = elf_ndxscn(s);
+
+ if (!gelf_getshdr(s, &sec->sh)) {
+ perror("gelf_getshdr");
+ return -1;
+ }
+
+ sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);
+ if (!sec->name) {
+ perror("elf_strptr");
+ return -1;
+ }
+
+ sec->elf_data = elf_getdata(s, NULL);
+ if (!sec->elf_data) {
+ perror("elf_getdata");
+ return -1;
+ }
+
+ if (sec->elf_data->d_off != 0 ||
+ sec->elf_data->d_size != sec->sh.sh_size) {
+ WARN("unexpected data attributes for %s", sec->name);
+ return -1;
+ }
+
+ sec->data = (unsigned long)sec->elf_data->d_buf;
+ sec->len = sec->elf_data->d_size;
+ }
+
+ /* sanity check, one more call to elf_nextscn() should return NULL */
+ if (elf_nextscn(elf->elf, s)) {
+ WARN("section entry mismatch");
+ return -1;
+ }
+
+ return 0;
+}
+
+static int read_symbols(struct elf *elf)
+{
+ struct section *symtab;
+ struct symbol *sym;
+ struct list_head *entry, *tmp;
+ int symbols_nr, i;
+
+ symtab = find_section_by_name(elf, ".symtab");
+ if (!symtab) {
+ WARN("missing symbol table");
+ return -1;
+ }
+
+ symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;
+
+ for (i = 0; i < symbols_nr; i++) {
+ sym = malloc(sizeof(*sym));
+ if (!sym) {
+ perror("malloc");
+ return -1;
+ }
+ memset(sym, 0, sizeof(*sym));
+
+ sym->index = i;
+
+ if (!gelf_getsym(symtab->elf_data, i, &sym->sym)) {
+ perror("gelf_getsym");
+ goto err;
+ }
+
+ sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
+ sym->sym.st_name);
+ if (!sym->name) {
+ perror("elf_strptr");
+ goto err;
+ }
+
+ sym->type = GELF_ST_TYPE(sym->sym.st_info);
+ sym->bind = GELF_ST_BIND(sym->sym.st_info);
+
+ if (sym->sym.st_shndx > SHN_UNDEF &&
+ sym->sym.st_shndx < SHN_LORESERVE) {
+ sym->sec = find_section_by_index(elf,
+ sym->sym.st_shndx);
+ if (!sym->sec) {
+ WARN("couldn't find section for symbol %s",
+ sym->name);
+ goto err;
+ }
+ if (sym->type == STT_SECTION) {
+ sym->name = sym->sec->name;
+ sym->sec->sym = sym;
+ }
+ } else
+ sym->sec = find_section_by_index(elf, 0);
+
+ sym->offset = sym->sym.st_value;
+ sym->len = sym->sym.st_size;
+
+ /* sorted insert into a per-section list */
+ entry = &sym->sec->symbols;
+ list_for_each_prev(tmp, &sym->sec->symbols) {
+ struct symbol *s;
+
+ s = list_entry(tmp, struct symbol, list);
+
+ if (sym->offset > s->offset) {
+ entry = tmp;
+ break;
+ }
+
+ if (sym->offset == s->offset && sym->len >= s->len) {
+ entry = tmp;
+ break;
+ }
+ }
+ list_add(&sym->list, entry);
+ }
+
+ return 0;
+
+err:
+ free(sym);
+ return -1;
+}
+
+static int read_relas(struct elf *elf)
+{
+ struct section *sec;
+ struct rela *rela;
+ int i;
+ unsigned int symndx;
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ if (sec->sh.sh_type != SHT_RELA)
+ continue;
+
+ sec->base = find_section_by_name(elf, sec->name + 5);
+ if (!sec->base) {
+ WARN("can't find base section for rela section %s",
+ sec->name);
+ return -1;
+ }
+
+ sec->base->rela = sec;
+
+ for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) {
+ rela = malloc(sizeof(*rela));
+ if (!rela) {
+ perror("malloc");
+ return -1;
+ }
+ memset(rela, 0, sizeof(*rela));
+
+ list_add_tail(&rela->list, &sec->relas);
+
+ if (!gelf_getrela(sec->elf_data, i, &rela->rela)) {
+ perror("gelf_getrela");
+ return -1;
+ }
+
+ rela->type = GELF_R_TYPE(rela->rela.r_info);
+ rela->addend = rela->rela.r_addend;
+ rela->offset = rela->rela.r_offset;
+ symndx = GELF_R_SYM(rela->rela.r_info);
+ rela->sym = find_symbol_by_index(elf, symndx);
+ if (!rela->sym) {
+ WARN("can't find rela entry symbol %d for %s",
+ symndx, sec->name);
+ return -1;
+ }
+ }
+ }
+
+ return 0;
+}
+
+struct elf *elf_open(const char *name)
+{
+ struct elf *elf;
+
+ elf_version(EV_CURRENT);
+
+ elf = malloc(sizeof(*elf));
+ if (!elf) {
+ perror("malloc");
+ return NULL;
+ }
+ memset(elf, 0, sizeof(*elf));
+
+ INIT_LIST_HEAD(&elf->sections);
+
+ elf->name = strdup(name);
+ if (!elf->name) {
+ perror("strdup");
+ goto err;
+ }
+
+ elf->fd = open(name, O_RDONLY);
+ if (elf->fd == -1) {
+ perror("open");
+ goto err;
+ }
+
+ elf->elf = elf_begin(elf->fd, ELF_C_READ_MMAP, NULL);
+ if (!elf->elf) {
+ perror("elf_begin");
+ goto err;
+ }
+
+ if (!gelf_getehdr(elf->elf, &elf->ehdr)) {
+ perror("gelf_getehdr");
+ goto err;
+ }
+
+ if (read_sections(elf))
+ goto err;
+
+ if (read_symbols(elf))
+ goto err;
+
+ if (read_relas(elf))
+ goto err;
+
+ return elf;
+
+err:
+ elf_close(elf);
+ return NULL;
+}
+
+void elf_close(struct elf *elf)
+{
+ struct section *sec, *tmpsec;
+ struct symbol *sym, *tmpsym;
+ struct rela *rela, *tmprela;
+
+ list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) {
+ list_for_each_entry_safe(sym, tmpsym, &sec->symbols, list) {
+ list_del(&sym->list);
+ free(sym);
+ }
+ list_for_each_entry_safe(rela, tmprela, &sec->relas, list) {
+ list_del(&rela->list);
+ free(rela);
+ }
+ list_del(&sec->list);
+ free(sec);
+ }
+ if (elf->name)
+ free(elf->name);
+ if (elf->fd > 0)
+ close(elf->fd);
+ if (elf->elf)
+ elf_end(elf->elf);
+ free(elf);
+}
diff --git a/scripts/stackvalidate/elf.h b/scripts/stackvalidate/elf.h
new file mode 100644
index 0000000..feb1f38
--- /dev/null
+++ b/scripts/stackvalidate/elf.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _STACKVALIDATE_ELF_H
+#define _STACKVALIDATE_ELF_H
+
+#include <stdio.h>
+#include <gelf.h>
+#include "list.h"
+
+#define WARN(format, ...) \
+ fprintf(stderr, \
+ "stackvalidate: %s: " format "\n", \
+ elf->name, ##__VA_ARGS__)
+
+#define WARN_FUNC(format, sec, offset, ...) \
+({ \
+ char *_str = offstr(sec, offset); \
+ WARN("%s: " format, _str, ##__VA_ARGS__); \
+ free(_str); \
+})
+
+struct section {
+ struct list_head list;
+ GElf_Shdr sh;
+ struct list_head symbols;
+ struct list_head relas;
+ struct section *base, *rela;
+ struct symbol *sym;
+ Elf_Data *elf_data;
+ char *name;
+ int index;
+ unsigned long data;
+ unsigned int len;
+};
+
+struct symbol {
+ struct list_head list;
+ GElf_Sym sym;
+ struct section *sec;
+ char *name;
+ int index;
+ unsigned char bind, type;
+ unsigned long offset;
+ unsigned int len;
+};
+
+struct rela {
+ struct list_head list;
+ GElf_Rela rela;
+ struct symbol *sym;
+ unsigned int type;
+ int offset;
+ int addend;
+};
+
+struct elf {
+ Elf *elf;
+ GElf_Ehdr ehdr;
+ int fd;
+ char *name;
+ struct list_head sections;
+};
+
+
+struct elf *elf_open(const char *name);
+struct section *find_section_by_name(struct elf *elf, const char *name);
+struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
+struct rela *find_rela_by_dest(struct section *sec, unsigned long offset);
+struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
+ unsigned int len);
+struct symbol *find_containing_func(struct section *sec, unsigned long offset);
+char *offstr(struct section *sec, unsigned long offset);
+void elf_close(struct elf *elf);
+
+
+
+#endif /* _STACKVALIDATE_ELF_H */
diff --git a/scripts/stackvalidate/list.h b/scripts/stackvalidate/list.h
new file mode 100644
index 0000000..25716b5
--- /dev/null
+++ b/scripts/stackvalidate/list.h
@@ -0,0 +1,217 @@
+#ifndef _LIST_H
+#define _LIST_H
+
+#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
+
+#define container_of(ptr, type, member) ({ \
+ const typeof(((type *)0)->member) *__mptr = (ptr); \
+ (type *)((char *)__mptr - offsetof(type, member)); })
+
+#define LIST_POISON1 ((void *) 0x00100100)
+#define LIST_POISON2 ((void *) 0x00200200)
+
+struct list_head {
+ struct list_head *next, *prev;
+};
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+#define LIST_HEAD(name) \
+ struct list_head name = LIST_HEAD_INIT(name)
+
+static inline void INIT_LIST_HEAD(struct list_head *list)
+{
+ list->next = list;
+ list->prev = list;
+}
+
+static inline void __list_add(struct list_head *new,
+ struct list_head *prev,
+ struct list_head *next)
+{
+ next->prev = new;
+ new->next = next;
+ new->prev = prev;
+ prev->next = new;
+}
+
+static inline void list_add(struct list_head *new, struct list_head *head)
+{
+ __list_add(new, head, head->next);
+}
+
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
+{
+ __list_add(new, head->prev, head);
+}
+
+static inline void __list_del(struct list_head *prev, struct list_head *next)
+{
+ next->prev = prev;
+ prev->next = next;
+}
+
+static inline void __list_del_entry(struct list_head *entry)
+{
+ __list_del(entry->prev, entry->next);
+}
+
+static inline void list_del(struct list_head *entry)
+{
+ __list_del(entry->prev, entry->next);
+ entry->next = LIST_POISON1;
+ entry->prev = LIST_POISON2;
+}
+
+static inline void list_replace(struct list_head *old,
+ struct list_head *new)
+{
+ new->next = old->next;
+ new->next->prev = new;
+ new->prev = old->prev;
+ new->prev->next = new;
+}
+
+static inline void list_replace_init(struct list_head *old,
+ struct list_head *new)
+{
+ list_replace(old, new);
+ INIT_LIST_HEAD(old);
+}
+
+static inline void list_del_init(struct list_head *entry)
+{
+ __list_del_entry(entry);
+ INIT_LIST_HEAD(entry);
+}
+
+static inline void list_move(struct list_head *list, struct list_head *head)
+{
+ __list_del_entry(list);
+ list_add(list, head);
+}
+
+static inline void list_move_tail(struct list_head *list,
+ struct list_head *head)
+{
+ __list_del_entry(list);
+ list_add_tail(list, head);
+}
+
+static inline int list_is_last(const struct list_head *list,
+ const struct list_head *head)
+{
+ return list->next == head;
+}
+
+static inline int list_empty(const struct list_head *head)
+{
+ return head->next == head;
+}
+
+static inline int list_empty_careful(const struct list_head *head)
+{
+ struct list_head *next = head->next;
+
+ return (next == head) && (next == head->prev);
+}
+
+static inline void list_rotate_left(struct list_head *head)
+{
+ struct list_head *first;
+
+ if (!list_empty(head)) {
+ first = head->next;
+ list_move_tail(first, head);
+ }
+}
+
+static inline int list_is_singular(const struct list_head *head)
+{
+ return !list_empty(head) && (head->next == head->prev);
+}
+
+#define list_entry(ptr, type, member) \
+ container_of(ptr, type, member)
+
+#define list_first_entry(ptr, type, member) \
+ list_entry((ptr)->next, type, member)
+
+#define list_last_entry(ptr, type, member) \
+ list_entry((ptr)->prev, type, member)
+
+#define list_first_entry_or_null(ptr, type, member) \
+ (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
+
+#define list_next_entry(pos, member) \
+ list_entry((pos)->member.next, typeof(*(pos)), member)
+
+#define list_prev_entry(pos, member) \
+ list_entry((pos)->member.prev, typeof(*(pos)), member)
+
+#define list_for_each(pos, head) \
+ for (pos = (head)->next; pos != (head); pos = pos->next)
+
+#define list_for_each_prev(pos, head) \
+ for (pos = (head)->prev; pos != (head); pos = pos->prev)
+
+#define list_for_each_safe(pos, n, head) \
+ for (pos = (head)->next, n = pos->next; pos != (head); \
+ pos = n, n = pos->next)
+
+#define list_for_each_prev_safe(pos, n, head) \
+ for (pos = (head)->prev, n = pos->prev; \
+ pos != (head); \
+ pos = n, n = pos->prev)
+
+#define list_for_each_entry(pos, head, member) \
+ for (pos = list_first_entry(head, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+#define list_for_each_entry_reverse(pos, head, member) \
+ for (pos = list_last_entry(head, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_prev_entry(pos, member))
+
+#define list_prepare_entry(pos, head, member) \
+ ((pos) ? : list_entry(head, typeof(*pos), member))
+
+#define list_for_each_entry_continue(pos, head, member) \
+ for (pos = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+#define list_for_each_entry_continue_reverse(pos, head, member) \
+ for (pos = list_prev_entry(pos, member); \
+ &pos->member != (head); \
+ pos = list_prev_entry(pos, member))
+
+#define list_for_each_entry_from(pos, head, member) \
+ for (; &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+#define list_for_each_entry_safe(pos, n, head, member) \
+ for (pos = list_first_entry(head, typeof(*pos), member), \
+ n = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_next_entry(n, member))
+
+#define list_for_each_entry_safe_continue(pos, n, head, member) \
+ for (pos = list_next_entry(pos, member), \
+ n = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_next_entry(n, member))
+
+#define list_for_each_entry_safe_from(pos, n, head, member) \
+ for (n = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_next_entry(n, member))
+
+#define list_for_each_entry_safe_reverse(pos, n, head, member) \
+ for (pos = list_last_entry(head, typeof(*pos), member), \
+ n = list_prev_entry(pos, member); \
+ &pos->member != (head); \
+ pos = n, n = list_prev_entry(n, member))
+
+#endif /* _LIST_H */
diff --git a/scripts/stackvalidate/special.c b/scripts/stackvalidate/special.c
new file mode 100644
index 0000000..c58de2a
--- /dev/null
+++ b/scripts/stackvalidate/special.c
@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This file reads all the special sections which have alternate instructions
+ * which can be patched in or redirected to at runtime.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "special.h"
+
+#define EX_ENTRY_SIZE 8
+#define EX_ORIG_OFFSET 0
+#define EX_NEW_OFFSET 4
+
+#define JUMP_ENTRY_SIZE 24
+#define JUMP_ORIG_OFFSET 0
+#define JUMP_NEW_OFFSET 8
+
+#define ALT_ENTRY_SIZE 13
+#define ALT_ORIG_OFFSET 0
+#define ALT_NEW_OFFSET 4
+#define ALT_FEATURE_OFFSET 8
+#define ALT_ORIG_LEN_OFFSET 10
+#define ALT_NEW_LEN_OFFSET 11
+
+#define X86_FEATURE_POPCNT 4*32+23
+
+struct special_entry {
+ char *sec;
+ bool group;
+ unsigned char size, orig, new;
+ unsigned char orig_len, new_len; /* group only */
+ unsigned char feature; /* ALTERNATIVE macro CPU feature */
+};
+
+struct special_entry entries[] = {
+ {
+ .sec = ".altinstructions",
+ .group = true,
+ .size = ALT_ENTRY_SIZE,
+ .orig = ALT_ORIG_OFFSET,
+ .orig_len = ALT_ORIG_LEN_OFFSET,
+ .new = ALT_NEW_OFFSET,
+ .new_len = ALT_NEW_LEN_OFFSET,
+ .feature = ALT_FEATURE_OFFSET,
+ },
+ {
+ .sec = "__jump_table",
+ .size = JUMP_ENTRY_SIZE,
+ .orig = JUMP_ORIG_OFFSET,
+ .new = JUMP_NEW_OFFSET,
+ },
+ {
+ .sec = "__ex_table",
+ .size = EX_ENTRY_SIZE,
+ .orig = EX_ORIG_OFFSET,
+ .new = EX_NEW_OFFSET,
+ },
+ {},
+};
+
+static int get_alt_entry(struct elf *elf, struct special_entry *entry,
+ struct section *sec, int index,
+ struct special_alt *alt)
+{
+ struct rela *orig_rela, *new_rela;
+ unsigned long offset;
+
+ offset = index * entry->size;
+
+ alt->group = entry->group;
+
+ if (alt->group) {
+ alt->orig_len = *(unsigned char *)(sec->data + offset +
+ entry->orig_len);
+ alt->new_len = *(unsigned char *)(sec->data + offset +
+ entry->new_len);
+ }
+
+ if (entry->feature) {
+ unsigned short feature;
+
+ feature = *(unsigned short *)(sec->data + offset +
+ entry->feature);
+
+ /*
+ * It has been requested that we don't validate the !POPCNT
+ * feature path which is a "very very small percentage of
+ * machines".
+ */
+ if (feature == X86_FEATURE_POPCNT)
+ alt->skip_orig = true;
+ }
+
+ orig_rela = find_rela_by_dest(sec, offset + entry->orig);
+ if (!orig_rela) {
+ WARN("%s: can't find orig rela",
+ offstr(sec, offset + entry->orig));
+ return -1;
+ }
+ if (orig_rela->sym->type != STT_SECTION) {
+ WARN("%s: don't know how to handle non-section rela symbol %s",
+ offstr(sec, offset + entry->orig),
+ orig_rela->sym->name);
+ return -1;
+ }
+
+ alt->orig_sec = orig_rela->sym->sec;
+ alt->orig_off = orig_rela->addend;
+
+ if (!entry->group || alt->new_len) {
+ new_rela = find_rela_by_dest(sec, offset + entry->new);
+ if (!new_rela) {
+ WARN("%s: can't find new rela",
+ offstr(sec, offset + entry->new));
+ return -1;
+ }
+ if (new_rela->sym->type != STT_SECTION) {
+ WARN("%s: don't know how to handle non-section rela symbol %s",
+ offstr(sec, offset + entry->new),
+ new_rela->sym->name);
+ return -1;
+ }
+
+ alt->new_sec = new_rela->sym->sec;
+ alt->new_off = (unsigned int)new_rela->addend;
+
+ /* _ASM_EXTABLE_EX hack */
+ if (alt->new_off >= 0x7ffffff0)
+ alt->new_off -= 0x7ffffff0;
+ }
+
+ return 0;
+}
+
+/*
+ * Read all the special sections and create a list of special_alt structs which
+ * describe all the alternate instructions which can be patched in or
+ * redirected to at runtime.
+ */
+int special_get_alts(struct elf *elf, struct list_head *alts)
+{
+ struct special_entry *entry;
+ struct section *sec;
+ unsigned int nr_entries;
+ struct special_alt *alt;
+ int index, ret;
+
+ INIT_LIST_HEAD(alts);
+
+ for (entry = entries; entry->sec; entry++) {
+ sec = find_section_by_name(elf, entry->sec);
+ if (!sec)
+ continue;
+
+ if (sec->len % entry->size != 0) {
+ WARN("%s size not a multiple of %d",
+ sec->name, JUMP_ENTRY_SIZE);
+ return -1;
+ }
+
+ nr_entries = sec->len / entry->size;
+
+ for (index = 0; index < nr_entries; index++) {
+ alt = malloc(sizeof(*alt));
+ if (!alt) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memset(alt, 0, sizeof(*alt));
+
+ ret = get_alt_entry(elf, entry, sec, index, alt);
+ if (ret)
+ return ret;
+
+ list_add_tail(&alt->list, alts);
+ }
+ }
+
+ return 0;
+}
diff --git a/scripts/stackvalidate/special.h b/scripts/stackvalidate/special.h
new file mode 100644
index 0000000..09b450f
--- /dev/null
+++ b/scripts/stackvalidate/special.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _SPECIAL_H
+#define _SPECIAL_H
+
+#include <stdbool.h>
+#include "elf.h"
+
+struct special_alt {
+ struct list_head list;
+
+ bool group;
+ bool skip_orig;
+
+ struct section *orig_sec;
+ unsigned long orig_off;
+
+ struct section *new_sec;
+ unsigned long new_off;
+
+ unsigned int orig_len, new_len; /* group only */
+};
+
+int special_get_alts(struct elf *elf, struct list_head *alts);
+
+#endif /* _SPECIAL_H */
diff --git a/scripts/stackvalidate/stackvalidate.c b/scripts/stackvalidate/stackvalidate.c
new file mode 100644
index 0000000..325b08b
--- /dev/null
+++ b/scripts/stackvalidate/stackvalidate.c
@@ -0,0 +1,949 @@
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * stackvalidate:
+ *
+ * This tool analyzes every .o file and ensures the validity of its stack trace
+ * metadata. It enforces a set of rules on asm code and C inline assembly code
+ * so that stack traces can be reliable.
+ *
+ * For more information, see Documentation/stack-validation.txt.
+ */
+
+#include <argp.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "elf.h"
+#include "arch.h"
+#include "special.h"
+
+#define STATE_FP_SAVED 0x1
+#define STATE_FP_SETUP 0x2
+
+int warnings;
+
+struct instruction {
+ struct list_head list;
+ struct section *sec;
+ unsigned long offset;
+ unsigned int len, state;
+ unsigned char type;
+ unsigned long immediate;
+ bool alt_group, visited, ignore;
+ struct symbol *call_dest;
+ struct instruction *jump_dest;
+ struct list_head alts;
+};
+
+struct list_head insns;
+
+struct alternative {
+ struct list_head list;
+ struct instruction *insn;
+};
+
+struct args {
+ char *args[1];
+ bool nofp;
+};
+struct args args;
+static const char args_doc[] = "file.o";
+static struct argp_option options[] = {
+ {"no-frame-pointer", 1, 0, 0, "Don't check frame pointers" },
+ {0},
+};
+static error_t parse_opt(int key, char *arg, struct argp_state *state)
+{
+ /* Get the input argument from argp_parse, which we
+ know is a pointer to our args structure. */
+ struct args *args = state->input;
+
+ switch (key) {
+ case 1: /* --no-frame-pointer */
+ args->nofp = true;
+ break;
+
+ case ARGP_KEY_ARG:
+ if (state->arg_num >= 1)
+ /* Too many arguments. */
+ argp_usage(state);
+ args->args[state->arg_num] = arg;
+ break;
+
+ case ARGP_KEY_END:
+ if (state->arg_num < 1)
+ /* Not enough arguments. */
+ argp_usage(state);
+ break;
+
+ default:
+ return ARGP_ERR_UNKNOWN;
+ }
+ return 0;
+}
+static struct argp argp = { options, parse_opt, args_doc, 0 };
+
+/*
+ * Check for the STACKVALIDATE_IGNORE_INSN macro.
+ */
+static bool ignore_insn(struct elf *elf, struct instruction *insn)
+{
+ struct section *macro_sec;
+ struct rela *rela;
+
+ macro_sec = find_section_by_name(elf, "__stackvalidate_ignore_insn");
+ if (!macro_sec || !macro_sec->rela)
+ return false;
+
+ list_for_each_entry(rela, ¯o_sec->rela->relas, list)
+ if (rela->sym->type == STT_SECTION &&
+ rela->sym == insn->sec->sym &&
+ rela->addend == insn->offset)
+ return true;
+
+ return false;
+}
+
+/*
+ * Check for the STACKVALIDATE_IGNORE_FUNC macro.
+ */
+static bool ignore_func(struct elf *elf, struct symbol *func)
+{
+ struct section *macro_sec;
+ struct rela *rela;
+
+ macro_sec = find_section_by_name(elf, "__stackvalidate_ignore_func");
+ if (!macro_sec || !macro_sec->rela)
+ return false;
+
+ list_for_each_entry(rela, ¯o_sec->rela->relas, list)
+ if (rela->sym->sec == func->sec &&
+ rela->addend == func->offset)
+ return true;
+
+
+ return false;
+}
+
+static struct instruction *find_instruction(struct section *sec,
+ unsigned long offset)
+{
+ struct instruction *insn;
+
+ list_for_each_entry(insn, &insns, list)
+ if (insn->sec == sec && insn->offset == offset)
+ return insn;
+
+ return NULL;
+}
+
+/*
+ * This checks to see if the given function is a "noreturn" function.
+ *
+ * For global functions which are outside the scope of this object file, we
+ * have to keep a manual list of them.
+ *
+ * For local functions, we have to detect them manually by simply looking for
+ * the lack of a return instruction.
+ */
+static bool dead_end_function(struct symbol *func)
+{
+ struct instruction *insn;
+
+ if (func->bind == STB_GLOBAL &&
+ (!strcmp(func->name, "__stack_chk_fail") ||
+ !strcmp(func->name, "panic") ||
+ !strcmp(func->name, "do_exit")))
+ return true;
+
+ if (!func->sec)
+ return false;
+
+ insn = find_instruction(func->sec, func->offset);
+ if (!insn)
+ return false;
+
+ list_for_each_entry_from(insn, &insns, list) {
+ if (insn->sec != func->sec ||
+ insn->offset >= func->offset + func->len)
+ break;
+
+ if (insn->type == INSN_RETURN)
+ return false;
+
+ if (insn->type == INSN_JUMP_UNCONDITIONAL) {
+ struct instruction *dest = insn->jump_dest;
+ struct symbol *dest_func;
+
+ if (!dest)
+ /* sibling call to another file */
+ return false;
+
+ if (dest->sec != func->sec ||
+ dest->offset < func->offset ||
+ dest->offset >= func->offset + func->len) {
+ /* local sibling call */
+ dest_func = find_symbol_by_offset(dest->sec,
+ dest->offset);
+ if (!dest_func)
+ continue;
+
+ return dead_end_function(dest_func);
+ }
+ }
+
+ if (insn->type == INSN_JUMP_DYNAMIC)
+ /* sibling call */
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * Call the arch-specific instruction decoder for all the instructions and add
+ * them to the global insns list.
+ */
+static int decode_instructions(struct elf *elf)
+{
+ struct section *sec;
+ unsigned long offset;
+ struct instruction *insn;
+ int ret;
+
+ INIT_LIST_HEAD(&insns);
+
+ list_for_each_entry(sec, &elf->sections, list) {
+
+ if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+ continue;
+
+ for (offset = 0; offset < sec->len; offset += insn->len) {
+ insn = malloc(sizeof(*insn));
+ memset(insn, 0, sizeof(*insn));
+
+ INIT_LIST_HEAD(&insn->alts);
+ insn->sec = sec;
+ insn->offset = offset;
+
+ ret = arch_decode_instruction(elf, sec, offset,
+ sec->len - offset,
+ &insn->len, &insn->type,
+ &insn->immediate);
+ if (ret)
+ return ret;
+
+ if (!insn->type || insn->type > INSN_LAST) {
+ WARN_FUNC("invalid instruction type %d",
+ insn->sec, insn->offset, insn->type);
+ return -1;
+ }
+
+ list_add_tail(&insn->list, &insns);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Warnings shouldn't be reported for ignored instructions. Set insn->ignore
+ * for each ignored instruction and each instruction contained in an ignored
+ * function.
+ */
+static void get_ignores(struct elf *elf)
+{
+ struct instruction *insn;
+ struct section *sec;
+ struct symbol *func;
+
+ list_for_each_entry(insn, &insns, list)
+ insn->ignore = ignore_insn(elf, insn);
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ list_for_each_entry(func, &sec->symbols, list) {
+ if (func->type != STT_FUNC)
+ continue;
+
+ if (!ignore_func(elf, func))
+ continue;
+
+ insn = find_instruction(sec, func->offset);
+ if (!insn)
+ continue;
+
+ list_for_each_entry_from(insn, &insns, list) {
+ if (insn->sec != func->sec ||
+ insn->offset >= func->offset + func->len)
+ break;
+
+ insn->ignore = true;
+ insn->visited = true;
+ }
+ }
+ }
+}
+
+/*
+ * Find the destination instructions for all jumps.
+ */
+static int get_jump_destinations(struct elf *elf)
+{
+ struct instruction *insn;
+ struct rela *rela;
+ struct section *dest_sec;
+ unsigned long dest_off;
+
+ list_for_each_entry(insn, &insns, list) {
+ if (insn->type != INSN_JUMP_CONDITIONAL &&
+ insn->type != INSN_JUMP_UNCONDITIONAL)
+ continue;
+
+ rela = find_rela_by_dest_range(insn->sec, insn->offset,
+ insn->len);
+ if (!rela) {
+ dest_sec = insn->sec;
+ dest_off = insn->offset + insn->len + insn->immediate;
+ } else if (rela->sym->type == STT_SECTION) {
+ dest_sec = rela->sym->sec;
+ dest_off = rela->addend + 4;
+ } else if (rela->sym->sec->index) {
+ dest_sec = rela->sym->sec;
+ dest_off = rela->sym->sym.st_value + rela->addend + 4;
+ } else {
+ /*
+ * This error (jump to another file) will be handled
+ * later in validate_functions().
+ */
+ continue;
+ }
+
+ insn->jump_dest = find_instruction(dest_sec, dest_off);
+ if (!insn->jump_dest && !insn->ignore) {
+
+ /*
+ * This is a special case where an alt instruction
+ * jumps past the end of the section. These are
+ * handled later.
+ */
+ if (!strcmp(insn->sec->name, ".altinstr_replacement"))
+ continue;
+
+ WARN_FUNC("can't find jump dest instruction at %s+0x%lx",
+ insn->sec, insn->offset, dest_sec->name,
+ dest_off);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Find the destination instructions for all calls.
+ */
+static int get_call_destinations(struct elf *elf)
+{
+ struct instruction *insn;
+ unsigned long dest_off;
+ struct rela *rela;
+
+ list_for_each_entry(insn, &insns, list) {
+ if (insn->type != INSN_CALL)
+ continue;
+
+ rela = find_rela_by_dest_range(insn->sec, insn->offset,
+ insn->len);
+ if (!rela) {
+ dest_off = insn->offset + insn->len + insn->immediate;
+ insn->call_dest = find_symbol_by_offset(insn->sec,
+ dest_off);
+ if (!insn->call_dest) {
+ WARN_FUNC("can't find call dest symbol at offset 0x%lx",
+ insn->sec, insn->offset, dest_off);
+ return -1;
+ }
+ } else if (rela->sym->type == STT_SECTION) {
+ insn->call_dest = find_symbol_by_offset(rela->sym->sec,
+ rela->addend+4);
+ if (!insn->call_dest ||
+ insn->call_dest->type != STT_FUNC) {
+ WARN_FUNC("can't find call dest symbol at %s+0x%x",
+ insn->sec, insn->offset,
+ rela->sym->sec->name,
+ rela->addend + 4);
+ return -1;
+ }
+ } else
+ insn->call_dest = rela->sym;
+ }
+
+ return 0;
+}
+
+/*
+ * The .alternatives section requires some extra special care, over and above
+ * what other special sections require:
+ *
+ * 1. Because alternatives are patched in-place, we need to insert a fake jump
+ * instruction at the end so that validate_branch() skips all the original
+ * replaced instructions when validating the new instruction path.
+ *
+ * 2. An added wrinkle is that the new instruction length might be zero. In
+ * that case the old instructions are replaced with noops. We simulate that
+ * by creating a fake jump as the only new instruction.
+ *
+ * 3. In some cases, the alternative section includes an instruction which
+ * conditionally jumps to the _end_ of the entry. We have to modify these
+ * jumps' destinations to point back to .text rather than the end of the
+ * entry in .altinstr_replacement.
+ *
+ * 4. It has been requested that we don't validate the !POPCNT feature path
+ * which is a "very very small percentage of machines".
+ */
+static int handle_group_alt(struct elf *elf, struct special_alt *special_alt,
+ struct instruction *orig_insn,
+ struct instruction **new_insn)
+{
+ struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump;
+ unsigned long dest_off;
+
+ last_orig_insn = NULL;
+ insn = orig_insn;
+ list_for_each_entry_from(insn, &insns, list) {
+ if (insn->sec != special_alt->orig_sec ||
+ insn->offset >= special_alt->orig_off + special_alt->orig_len)
+ break;
+
+ if (special_alt->skip_orig)
+ insn->ignore = true;
+
+ insn->alt_group = true;
+ last_orig_insn = insn;
+ }
+
+ if (list_is_last(&last_orig_insn->list, &insns) ||
+ list_next_entry(last_orig_insn, list)->sec != special_alt->orig_sec) {
+ WARN("%s: don't know how to handle alternatives at end of section",
+ special_alt->orig_sec->name);
+ return -1;
+ }
+
+ fake_jump = malloc(sizeof(*fake_jump));
+ if (!fake_jump) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memset(fake_jump, 0, sizeof(*fake_jump));
+ INIT_LIST_HEAD(&fake_jump->alts);
+ fake_jump->sec = special_alt->new_sec;
+ fake_jump->offset = -1;
+ fake_jump->type = INSN_JUMP_UNCONDITIONAL;
+ fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
+
+ if (!special_alt->new_len) {
+ *new_insn = fake_jump;
+ return 0;
+ }
+
+ last_new_insn = NULL;
+ insn = *new_insn;
+ list_for_each_entry_from(insn, &insns, list) {
+ if (insn->sec != special_alt->new_sec ||
+ insn->offset >= special_alt->new_off + special_alt->new_len)
+ break;
+
+ last_new_insn = insn;
+
+ if (insn->type != INSN_JUMP_CONDITIONAL &&
+ insn->type != INSN_JUMP_UNCONDITIONAL)
+ continue;
+
+ if (!insn->immediate)
+ continue;
+
+ dest_off = insn->offset + insn->len + insn->immediate;
+ if (dest_off == special_alt->new_off + special_alt->new_len)
+ insn->jump_dest = fake_jump;
+
+ if (!insn->jump_dest) {
+ WARN_FUNC("can't find alternative jump destination",
+ insn->sec, insn->offset);
+ return -1;
+ }
+ }
+
+ if (!last_new_insn) {
+ WARN_FUNC("can't find last new alternative instruction",
+ special_alt->new_sec, special_alt->new_off);
+ return -1;
+ }
+
+ list_add(&fake_jump->list, &last_new_insn->list);
+
+ return 0;
+}
+
+/*
+ * Read all the special sections which have alternate instructions which can be
+ * patched in or redirected to at runtime. Each instruction having alternate
+ * instruction(s) has them added to its insn->alts list, which will be
+ * traversed in validate_branch().
+ */
+static int get_special_section_alts(struct elf *elf)
+{
+ struct list_head special_alts;
+ struct instruction *orig_insn, *new_insn;
+ struct special_alt *special_alt, *tmp;
+ struct alternative *alt;
+ int ret;
+
+ ret = special_get_alts(elf, &special_alts);
+ if (ret)
+ return ret;
+
+ list_for_each_entry_safe(special_alt, tmp, &special_alts, list) {
+ alt = malloc(sizeof(*alt));
+ if (!alt) {
+ WARN("malloc failed");
+ ret = -1;
+ goto out;
+ }
+
+ orig_insn = find_instruction(special_alt->orig_sec,
+ special_alt->orig_off);
+ if (!orig_insn) {
+ WARN_FUNC("special: can't find orig instruction",
+ special_alt->orig_sec, special_alt->orig_off);
+ ret = -1;
+ goto out;
+ }
+
+ new_insn = NULL;
+ if (!special_alt->group || special_alt->new_len) {
+ new_insn = find_instruction(special_alt->new_sec,
+ special_alt->new_off);
+ if (!new_insn) {
+ WARN_FUNC("special: can't find new instruction",
+ special_alt->new_sec,
+ special_alt->new_off);
+ ret = -1;
+ goto out;
+ }
+ }
+
+ if (special_alt->group) {
+ ret = handle_group_alt(elf, special_alt, orig_insn,
+ &new_insn);
+ if (ret)
+ goto out;
+ }
+
+ alt->insn = new_insn;
+ list_add_tail(&alt->list, &orig_insn->alts);
+
+ list_del(&special_alt->list);
+ free(special_alt);
+ }
+
+out:
+ return ret;
+}
+
+/*
+ * For some switch statements, gcc generates a jump table in the .rodata
+ * section which contains a list of addresses within the function to jump to.
+ * This finds these jump tables and adds them to the insn->alts lists.
+ */
+static int get_switch_alts(struct elf *elf)
+{
+ struct instruction *insn, *alt_insn;
+ struct rela *rodata_rela, *rela;
+ struct section *rodata;
+ struct symbol *func;
+ struct alternative *alt;
+
+ list_for_each_entry(insn, &insns, list) {
+ if (insn->type != INSN_JUMP_DYNAMIC)
+ continue;
+
+ rodata_rela = find_rela_by_dest_range(insn->sec, insn->offset,
+ insn->len);
+ if (!rodata_rela || strcmp(rodata_rela->sym->name, ".rodata"))
+ continue;
+
+ rodata = find_section_by_name(elf, ".rodata");
+ if (!rodata || !rodata->rela)
+ continue;
+
+ rela = find_rela_by_dest(rodata, rodata_rela->addend);
+ if (!rela)
+ continue;
+
+ func = find_containing_func(insn->sec, insn->offset);
+ if (!func) {
+ WARN_FUNC("can't find containing func",
+ insn->sec, insn->offset);
+ return -1;
+ }
+
+ list_for_each_entry_from(rela, &rodata->rela->relas, list) {
+ if (rela->sym->sec != insn->sec ||
+ rela->addend <= func->offset ||
+ rela->addend >= func->offset + func->len)
+ break;
+
+ alt_insn = find_instruction(insn->sec, rela->addend);
+ if (!alt_insn) {
+ WARN("%s: can't find instruction at %s+0x%x",
+ rodata->rela->name, insn->sec->name,
+ rela->addend);
+ return -1;
+ }
+
+ alt = malloc(sizeof(*alt));
+ if (!alt) {
+ WARN("malloc failed");
+ return -1;
+ }
+
+ alt->insn = alt_insn;
+ list_add_tail(&alt->list, &insn->alts);
+ }
+ }
+
+ return 0;
+}
+
+static int decode_sections(struct elf *elf)
+{
+ int ret;
+
+ ret = decode_instructions(elf);
+ if (ret)
+ return ret;
+
+ get_ignores(elf);
+
+ ret = get_jump_destinations(elf);
+ if (ret)
+ return ret;
+
+ ret = get_call_destinations(elf);
+ if (ret)
+ return ret;
+
+ ret = get_special_section_alts(elf);
+ if (ret)
+ return ret;
+
+ ret = get_switch_alts(elf);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+/*
+ * Follow the branch starting at the given instruction, and recursively follow
+ * any other branches (jumps). Meanwhile, track the frame pointer state at
+ * each instruction and validate all the rules described in
+ * Documentation/stack-validation.txt.
+ */
+static int validate_branch(struct elf *elf, struct instruction *first,
+ unsigned char first_state)
+{
+ struct alternative *alt;
+ struct instruction *insn;
+ struct section *sec;
+ unsigned char state;
+ int ret, warnings = 0;
+
+ insn = first;
+ sec = insn->sec;
+ state = first_state;
+
+ if (insn->alt_group && list_empty(&insn->alts)) {
+ WARN_FUNC("don't know how to handle branch to middle of alternative instruction group",
+ sec, insn->offset);
+ warnings++;
+ }
+
+ while (1) {
+ if (insn->visited) {
+ if (insn->state != state) {
+ WARN_FUNC("frame pointer state mismatch",
+ sec, insn->offset);
+ warnings++;
+ }
+
+ return warnings;
+ }
+
+ insn->visited = true;
+ insn->state = state;
+
+ list_for_each_entry(alt, &insn->alts, list) {
+ ret = validate_branch(elf, alt->insn, state);
+ warnings += ret;
+ }
+
+ switch (insn->type) {
+
+ case INSN_FP_SAVE:
+ if (!args.nofp) {
+ if (insn->state & STATE_FP_SAVED) {
+ WARN_FUNC("duplicate frame pointer save",
+ sec, insn->offset);
+ warnings++;
+ }
+ state |= STATE_FP_SAVED;
+ }
+ break;
+
+ case INSN_FP_SETUP:
+ if (!args.nofp) {
+ if (insn->state & STATE_FP_SETUP) {
+ WARN_FUNC("duplicate frame pointer setup",
+ sec, insn->offset);
+ warnings++;
+ }
+ state |= STATE_FP_SETUP;
+ }
+ break;
+
+ case INSN_FP_RESTORE:
+ if (!args.nofp) {
+ if (!insn->state) {
+ WARN_FUNC("frame pointer restore without save/setup",
+ sec, insn->offset);
+ warnings++;
+ }
+ state &= ~STATE_FP_SAVED;
+ state &= ~STATE_FP_SETUP;
+ }
+ break;
+
+ case INSN_RETURN:
+ if (!args.nofp && insn->state) {
+ WARN_FUNC("return without frame pointer restore",
+ sec, insn->offset);
+ warnings++;
+ }
+ return warnings;
+
+ case INSN_CALL:
+ if (insn->call_dest->type == STT_NOTYPE &&
+ !strcmp(insn->call_dest->name, "__fentry__"))
+ break;
+
+ if (dead_end_function(insn->call_dest))
+ return warnings;
+
+ if (!args.nofp && !insn->state && !insn->ignore) {
+ WARN_FUNC("call without frame pointer save/setup",
+ sec, insn->offset);
+ warnings++;
+ }
+ break;
+
+ case INSN_CALL_DYNAMIC:
+ if (!args.nofp && !insn->state && !insn->ignore) {
+ WARN_FUNC("call without frame pointer save/setup",
+ sec, insn->offset);
+ warnings++;
+ }
+ break;
+
+ case INSN_JUMP_CONDITIONAL:
+ case INSN_JUMP_UNCONDITIONAL:
+ if (insn->jump_dest) {
+ ret = validate_branch(elf, insn->jump_dest,
+ state);
+ warnings += ret;
+ } else if (insn->state) {
+ WARN_FUNC("sibling call from callable instruction with changed frame pointer",
+ sec, insn->offset);
+ warnings++;
+ } /* else it's a sibling call */
+
+ if (insn->type == INSN_JUMP_UNCONDITIONAL)
+ return warnings;
+
+ break;
+
+ case INSN_JUMP_DYNAMIC:
+ if (list_empty(&insn->alts) && insn->state &&
+ !insn->ignore) {
+ WARN_FUNC("sibling call from callable instruction with changed frame pointer",
+ sec, insn->offset);
+ warnings++;
+ }
+
+ return warnings;
+
+ case INSN_CONTEXT_SWITCH:
+ if (!insn->ignore) {
+ WARN_FUNC("kernel entry/exit from callable instruction",
+ sec, insn->offset);
+ warnings++;
+ }
+
+ return warnings;
+
+ case INSN_BUG:
+ return warnings;
+
+ }
+
+ insn = list_next_entry(insn, list);
+
+ if (&insn->list == &insns || insn->sec != sec) {
+ WARN("%s: unexpected end of section", sec->name);
+ warnings++;
+ return warnings;
+ }
+ }
+
+ return warnings;
+}
+
+static int validate_functions(struct elf *elf)
+{
+ struct section *sec;
+ struct symbol *func;
+ struct instruction *insn;
+ int ret, warnings = 0;
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ list_for_each_entry(func, &sec->symbols, list) {
+ if (func->type != STT_FUNC)
+ continue;
+
+ insn = find_instruction(sec, func->offset);
+ if (!insn) {
+ WARN("%s(): can't find starting instruction",
+ func->name);
+ warnings++;
+ continue;
+ }
+
+ ret = validate_branch(elf, insn, 0);
+ warnings += ret;
+ }
+ }
+
+ list_for_each_entry(sec, &elf->sections, list) {
+ list_for_each_entry(func, &sec->symbols, list) {
+ if (func->type != STT_FUNC)
+ continue;
+
+ insn = find_instruction(sec, func->offset);
+ if (!insn)
+ continue;
+
+ list_for_each_entry_from(insn, &insns, list) {
+ if (insn->sec != func->sec ||
+ insn->offset >= func->offset + func->len)
+ break;
+
+ if (!insn->visited && insn->type != INSN_NOP) {
+ WARN_FUNC("function has unreachable instruction",
+ insn->sec, insn->offset);
+ warnings++;
+ }
+
+ insn->visited = true;
+ }
+ }
+ }
+
+ return warnings;
+}
+
+static int validate_uncallable_instructions(struct elf *elf)
+{
+ struct instruction *insn;
+ int warnings = 0;
+
+ list_for_each_entry(insn, &insns, list) {
+ if (!insn->visited && insn->type == INSN_RETURN &&
+ !insn->ignore) {
+ WARN_FUNC("return instruction outside of a callable function",
+ insn->sec, insn->offset);
+ warnings++;
+ }
+ }
+
+ return warnings;
+}
+
+static void cleanup(struct elf *elf)
+{
+ struct instruction *insn, *tmpinsn;
+ struct alternative *alt, *tmpalt;
+
+ list_for_each_entry_safe(insn, tmpinsn, &insns, list) {
+ list_for_each_entry_safe(alt, tmpalt, &insn->alts, list) {
+ list_del(&alt->list);
+ free(alt);
+ }
+ list_del(&insn->list);
+ free(insn);
+ }
+ elf_close(elf);
+}
+
+int main(int argc, char *argv[])
+{
+ struct elf *elf;
+ int ret = 0, warnings = 0;
+
+ argp_parse(&argp, argc, argv, 0, 0, &args);
+
+ elf = elf_open(args.args[0]);
+ if (!elf) {
+ fprintf(stderr, "error reading elf file %s\n", args.args[0]);
+ return 1;
+ }
+
+ ret = decode_sections(elf);
+ if (ret < 0)
+ goto out;
+ warnings += ret;
+
+ ret = validate_functions(elf);
+ if (ret < 0)
+ goto out;
+ warnings += ret;
+
+ ret = validate_uncallable_instructions(elf);
+ if (ret < 0)
+ goto out;
+ warnings += ret;
+
+out:
+ cleanup(elf);
+
+ /* ignore warnings for now until we get all the code cleaned up */
+ if (ret || warnings)
+ return 0;
+ return 0;
+}
--
2.1.0
Tell stackvalidate to skip validation of the following code:
- boot image
- vdso image
- kexec purgatory
- realmode
- efi libstub
They all run outside the kernel's normal mode of operation and they
don't affect runtime kernel stack traces, so they're free to skirt the
stackvalidate rules.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/boot/Makefile | 3 ++-
arch/x86/boot/compressed/Makefile | 3 ++-
arch/x86/entry/vdso/Makefile | 5 ++++-
arch/x86/purgatory/Makefile | 2 ++
arch/x86/realmode/Makefile | 4 +++-
arch/x86/realmode/rm/Makefile | 3 ++-
drivers/firmware/efi/libstub/Makefile | 1 +
7 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 0d553e5..d31808c 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -14,7 +14,8 @@
# Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
# The number is the same as you would ordinarily press at bootup.
-KASAN_SANITIZE := n
+KASAN_SANITIZE := n
+STACKVALIDATE := n
SVGA_MODE := -DSVGA_MODE=NORMAL_VGA
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 0a291cd..530a46f 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -16,7 +16,8 @@
# (see scripts/Makefile.lib size_append)
# compressed vmlinux.bin.all + u32 size of vmlinux.bin.all
-KASAN_SANITIZE := n
+KASAN_SANITIZE := n
+STACKVALIDATE := n
targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 96c0617..ccaf812 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -3,7 +3,9 @@
#
KBUILD_CFLAGS += $(DISABLE_LTO)
-KASAN_SANITIZE := n
+
+KASAN_SANITIZE := n
+STACKVALIDATE := n
VDSO64-$(CONFIG_X86_64) := y
VDSOX32-$(CONFIG_X86_X32_ABI) := y
@@ -15,6 +17,7 @@ vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
# files to link into kernel
obj-y += vma.o
+STACKVALIDATE_vma.o := y
# vDSO images to build
vdso_img-$(VDSO64-y) += 64
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 2c835e3..a736c19 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -1,3 +1,5 @@
+STACKVALIDATE := n
+
purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string.o
targets += $(purgatory-y)
diff --git a/arch/x86/realmode/Makefile b/arch/x86/realmode/Makefile
index e02c2c6..7a2d4df 100644
--- a/arch/x86/realmode/Makefile
+++ b/arch/x86/realmode/Makefile
@@ -6,7 +6,9 @@
# for more details.
#
#
-KASAN_SANITIZE := n
+KASAN_SANITIZE := n
+STACKVALIDATE := n
+
subdir- := rm
obj-y += init.o
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 2730d77..d462a57 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -6,7 +6,8 @@
# for more details.
#
#
-KASAN_SANITIZE := n
+KASAN_SANITIZE := n
+STACKVALIDATE := n
always := realmode.bin realmode.relocs
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 816dbe9..b392f3f 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -20,6 +20,7 @@ KBUILD_CFLAGS := $(cflags-y) \
GCOV_PROFILE := n
KASAN_SANITIZE := n
+STACKVALIDATE := n
lib-y := efi-stub-helper.o
lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o
--
2.1.0
Add new stackvalidate ignore macros: STACKVALIDATE_IGNORE_INSN and
STACKVALIDATE_IGNORE_FUNC. These can be used to tell stackvalidate to
skip validation of an instruction or a function, respectively.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/stackvalidate.h | 45 ++++++++++++++++++++++++++++++++++++
arch/x86/kernel/vmlinux.lds.S | 5 +++-
include/linux/stackvalidate.h | 28 ++++++++++++++++++++++
3 files changed, 77 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/include/asm/stackvalidate.h
create mode 100644 include/linux/stackvalidate.h
diff --git a/arch/x86/include/asm/stackvalidate.h b/arch/x86/include/asm/stackvalidate.h
new file mode 100644
index 0000000..95db052
--- /dev/null
+++ b/arch/x86/include/asm/stackvalidate.h
@@ -0,0 +1,45 @@
+#ifndef _ASM_X86_STACKVALIDATE_H
+#define _ASM_X86_STACKVALIDATE_H
+
+#include <asm/asm.h>
+
+#ifdef __ASSEMBLY__
+
+/*
+ * This asm macro tells the stack validation script to ignore the instruction
+ * immediately after the macro. It should only be used in special cases where
+ * you're 100% sure it won't affect the reliability of frame pointers and
+ * kernel stack traces.
+ *
+ * For more information, see Documentation/stack-validation.txt.
+ */
+.macro STACKVALIDATE_IGNORE_INSN
+#ifdef CONFIG_STACK_VALIDATION
+ .Lstackvalidate_ignore_\@:
+ .pushsection __stackvalidate_ignore_insn, "a"
+ _ASM_ALIGN
+ .long .Lstackvalidate_ignore_\@ - .
+ .popsection
+#endif
+.endm
+
+#else /* !__ASSEMBLY__ */
+
+#ifdef CONFIG_STACK_VALIDATION
+
+#define STACKVALIDATE_IGNORE_INSN \
+ "1:\n" \
+ ".pushsection __stackvalidate_ignore_insn, \"a\"\n" \
+ _ASM_ALIGN "\n" \
+ ".long 1b - .\n" \
+ ".popsection\n"
+
+#else /* !CONFIG_STACK_VALIDATION */
+
+#define STACKVALIDATE_IGNORE_INSN ""
+
+#endif /* CONFIG_STACK_VALIDATION */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_X86_STACKVALIDATE_H */
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 00bf300..f2f8d7a 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -332,7 +332,10 @@ SECTIONS
/* Sections to be discarded */
DISCARDS
- /DISCARD/ : { *(.eh_frame) }
+ /DISCARD/ : {
+ *(.eh_frame)
+ *(__stackvalidate_ignore_*)
+ }
}
diff --git a/include/linux/stackvalidate.h b/include/linux/stackvalidate.h
new file mode 100644
index 0000000..4ae242c
--- /dev/null
+++ b/include/linux/stackvalidate.h
@@ -0,0 +1,28 @@
+#ifndef _LINUX_STACKVALIDATE_H
+#define _LINUX_STACKVALIDATE_H
+
+#include <asm/stackvalidate.h>
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_STACK_VALIDATION
+/*
+ * This C macro tells the stack validation script to ignore the function. It
+ * should only be used in special cases where you're 100% sure it won't affect
+ * the reliability of frame pointers and kernel stack traces.
+ *
+ * For more information, see Documentation/stack-validation.txt.
+ */
+#define STACKVALIDATE_IGNORE_FUNC(_func) \
+ static void __used __section(__stackvalidate_ignore_func) \
+ *__stackvalidate_ignore_func_##_func = _func
+
+#else /* !CONFIG_STACK_VALIDATION */
+
+#define STACKVALIDATE_IGNORE_FUNC(_func)
+
+#endif /* CONFIG_STACK_VALIDATION */
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _LINUX_STACKVALIDATE_H */
--
2.1.0
If a hypercall is inlined at the beginning of a function, gcc can insert
the call instruction before setting up a stack frame, which breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace.
Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by
listing the stack pointer as an output operand for the hypercall inline
asm statements.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/xen/hypercall.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index ca08a27..4488fbc 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -110,9 +110,10 @@ extern struct { char _entry[32]; } hypercall_page[];
register unsigned long __arg2 asm(__HYPERCALL_ARG2REG) = __arg2; \
register unsigned long __arg3 asm(__HYPERCALL_ARG3REG) = __arg3; \
register unsigned long __arg4 asm(__HYPERCALL_ARG4REG) = __arg4; \
- register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5;
+ register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5; \
+ register void *__sp asm(_ASM_SP);
-#define __HYPERCALL_0PARAM "=r" (__res)
+#define __HYPERCALL_0PARAM "=r" (__res), "+r" (__sp)
#define __HYPERCALL_1PARAM __HYPERCALL_0PARAM, "+r" (__arg1)
#define __HYPERCALL_2PARAM __HYPERCALL_1PARAM, "+r" (__arg2)
#define __HYPERCALL_3PARAM __HYPERCALL_2PARAM, "+r" (__arg3)
--
2.1.0
If a PVOP call macro is inlined at the beginning of a function, gcc can
insert the call instruction before setting up a stack frame, which
breaks frame pointer convention if CONFIG_FRAME_POINTER is enabled and
can result in a bad stack trace.
Force a stack frame to be created by listing the stack pointer as an
output operand for the PVOP inline asm statements.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/paravirt_types.h | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index ce029e4..1812294 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -497,8 +497,9 @@ int paravirt_disable_iospace(void);
* makes sure the incoming and outgoing types are always correct.
*/
#ifdef CONFIG_X86_32
-#define PVOP_VCALL_ARGS \
- unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx
+#define PVOP_VCALL_ARGS \
+ unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx; \
+ register void *__sp asm("esp")
#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
#define PVOP_CALL_ARG1(x) "a" ((unsigned long)(x))
@@ -516,9 +517,10 @@ int paravirt_disable_iospace(void);
#define VEXTRA_CLOBBERS
#else /* CONFIG_X86_64 */
/* [re]ax isn't an arg, but the return val */
-#define PVOP_VCALL_ARGS \
- unsigned long __edi = __edi, __esi = __esi, \
- __edx = __edx, __ecx = __ecx, __eax = __eax
+#define PVOP_VCALL_ARGS \
+ unsigned long __edi = __edi, __esi = __esi, \
+ __edx = __edx, __ecx = __ecx, __eax = __eax; \
+ register void *__sp asm("rsp")
#define PVOP_CALL_ARGS PVOP_VCALL_ARGS
#define PVOP_CALL_ARG1(x) "D" ((unsigned long)(x))
@@ -557,7 +559,7 @@ int paravirt_disable_iospace(void);
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
- : call_clbr \
+ : "+r" (__sp), call_clbr \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
@@ -567,7 +569,7 @@ int paravirt_disable_iospace(void);
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
- : call_clbr \
+ : "+r" (__sp), call_clbr \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
@@ -594,7 +596,7 @@ int paravirt_disable_iospace(void);
asm volatile(pre \
paravirt_alt(PARAVIRT_CALL) \
post \
- : call_clbr \
+ : "+r" (__sp), call_clbr \
: paravirt_type(op), \
paravirt_clobber(clbr), \
##__VA_ARGS__ \
--
2.1.0
A function created with the PV_CALLEE_SAVE_REGS_THUNK macro doesn't set
up a new stack frame before the call instruction, which breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace. Also, the thunk functions aren't annotated as ELF
callable functions.
Create a stack frame when CONFIG_FRAME_POINTER is enabled and add the
ELF function type.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/paravirt.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index c2be037..2545f3e 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -13,6 +13,7 @@
#include <linux/bug.h>
#include <linux/types.h>
#include <linux/cpumask.h>
+#include <asm/frame.h>
static inline int paravirt_enabled(void)
{
@@ -772,15 +773,19 @@ static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock,
* call. The return value in rax/eax will not be saved, even for void
* functions.
*/
+#define PV_THUNK_NAME(func) "__raw_callee_save_" #func
#define PV_CALLEE_SAVE_REGS_THUNK(func) \
extern typeof(func) __raw_callee_save_##func; \
\
asm(".pushsection .text;" \
- ".globl __raw_callee_save_" #func " ; " \
- "__raw_callee_save_" #func ": " \
+ ".globl " PV_THUNK_NAME(func) ";" \
+ ".type " PV_THUNK_NAME(func) ", @function;" \
+ PV_THUNK_NAME(func) ":" \
+ FRAME \
PV_SAVE_ALL_CALLER_REGS \
"call " #func ";" \
PV_RESTORE_ALL_CALLER_REGS \
+ ENDFRAME \
"ret;" \
".popsection")
--
2.1.0
Paravirt thunk functions aren't aligned, which can impact performance
and is inconsistent with gcc-generated functions.
Align them at 16-byte boundaries to be consistent with gcc functions.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/include/asm/paravirt.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 2545f3e..5dcbf17 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -778,6 +778,7 @@ static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock,
extern typeof(func) __raw_callee_save_##func; \
\
asm(".pushsection .text;" \
+ ".align 16;" \
".globl " PV_THUNK_NAME(func) ";" \
".type " PV_THUNK_NAME(func) ", @function;" \
PV_THUNK_NAME(func) ":" \
--
2.1.0
vide() is a callable function, but is missing the ELF function type,
which confuses tools like stackvalidate.
Properly annotate it to be a callable function. The generated code is
unchanged.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/kernel/cpu/amd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 51ad2af..6507bab6 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -74,7 +74,10 @@ static inline int wrmsrl_amd_safe(unsigned msr, unsigned long long val)
*/
extern __visible void vide(void);
-__asm__(".globl vide\n\t.align 4\nvide: ret");
+__asm__(".globl vide;"
+ ".type vide, @function;"
+ ".align 4;"
+ "vide: ret;");
static void init_amd_k5(struct cpuinfo_x86 *c)
{
--
2.1.0
stackvalidate reports a false positive warning for the ljmp instruction
in machine_real_restart(). Normally, ljmp isn't allowed in a function,
but this is a special case where it's jumping into real mode.
Add the jumps to a whitelist which tells stackvalidate to ignore them.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/kernel/reboot.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 86db4bc..0931d87 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -9,6 +9,7 @@
#include <linux/sched.h>
#include <linux/tboot.h>
#include <linux/delay.h>
+#include <linux/stackvalidate.h>
#include <acpi/reboot.h>
#include <asm/io.h>
#include <asm/apic.h>
@@ -97,11 +98,13 @@ void __noreturn machine_real_restart(unsigned int type)
/* Jump to the identity-mapped low memory code */
#ifdef CONFIG_X86_32
- asm volatile("jmpl *%0" : :
+ asm volatile(STACKVALIDATE_IGNORE_INSN
+ "jmpl *%0;" : :
"rm" (real_mode_header->machine_real_restart_asm),
"a" (type));
#else
- asm volatile("ljmpl *%0" : :
+ asm volatile(STACKVALIDATE_IGNORE_INSN
+ "ljmpl *%0" : :
"m" (real_mode_header->machine_real_restart_asm),
"D" (type));
#endif
--
2.1.0
stackvalidate reports the following false positive warnings:
stackvalidate: arch/x86/xen/enlighten.o: xen_cpuid()+0x41: can't find jump dest instruction at .text+0x108
stackvalidate: arch/x86/xen/enlighten.o: xen_setup_gdt.constprop.23()+0x2e: kernel entry/exit from callable instruction
The first warning is due to xen_cpuid()'s use of XEN_EMULATE_PREFIX to
insert some fake instructions which stackvalidate doesn't know how to
decode.
The second warning is due to xen_setup_gdt()'s use of an lret
instruction, which stackvalidate normally doesn't allow in callable
functions. But this seems to be a valid use of the instruction.
Add both functions to the stackvalidate whitelist. This results in no
actual changes to the generated code.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/xen/enlighten.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 32136bf..8091836 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -32,6 +32,7 @@
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/edd.h>
+#include <linux/stackvalidate.h>
#include <xen/xen.h>
#include <xen/events.h>
@@ -345,8 +346,8 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
*cx &= maskecx;
*cx |= setecx;
*dx &= maskedx;
-
}
+STACKVALIDATE_IGNORE_FUNC(xen_cpuid);
static bool __init xen_check_mwait(void)
{
@@ -1403,6 +1404,7 @@ static void __ref xen_setup_gdt(int cpu)
pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
pv_cpu_ops.load_gdt = xen_load_gdt;
}
+STACKVALIDATE_IGNORE_FUNC(xen_setup_gdt);
#ifdef CONFIG_XEN_PVH
/*
--
2.1.0
aesni-intel_asm.S has several callable non-leaf functions which don't
honor CONFIG_FRAME_POINTER, which can result in bad stack traces.
Create stack frames for them when CONFIG_FRAME_POINTER is enabled.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/crypto/aesni-intel_asm.S | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/arch/x86/crypto/aesni-intel_asm.S b/arch/x86/crypto/aesni-intel_asm.S
index 6bd2c6c..3df557b 100644
--- a/arch/x86/crypto/aesni-intel_asm.S
+++ b/arch/x86/crypto/aesni-intel_asm.S
@@ -31,6 +31,7 @@
#include <linux/linkage.h>
#include <asm/inst.h>
+#include <asm/frame.h>
/*
* The following macros are used to move an (un)aligned 16 byte value to/from
@@ -1800,6 +1801,7 @@ ENDPROC(_key_expansion_256b)
* unsigned int key_len)
*/
ENTRY(aesni_set_key)
+ FRAME
#ifndef __x86_64__
pushl KEYP
movl 8(%esp), KEYP # ctx
@@ -1905,6 +1907,7 @@ ENTRY(aesni_set_key)
#ifndef __x86_64__
popl KEYP
#endif
+ ENDFRAME
ret
ENDPROC(aesni_set_key)
@@ -1912,6 +1915,7 @@ ENDPROC(aesni_set_key)
* void aesni_enc(struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src)
*/
ENTRY(aesni_enc)
+ FRAME
#ifndef __x86_64__
pushl KEYP
pushl KLEN
@@ -1927,6 +1931,7 @@ ENTRY(aesni_enc)
popl KLEN
popl KEYP
#endif
+ ENDFRAME
ret
ENDPROC(aesni_enc)
@@ -2101,6 +2106,7 @@ ENDPROC(_aesni_enc4)
* void aesni_dec (struct crypto_aes_ctx *ctx, u8 *dst, const u8 *src)
*/
ENTRY(aesni_dec)
+ FRAME
#ifndef __x86_64__
pushl KEYP
pushl KLEN
@@ -2117,6 +2123,7 @@ ENTRY(aesni_dec)
popl KLEN
popl KEYP
#endif
+ ENDFRAME
ret
ENDPROC(aesni_dec)
@@ -2292,6 +2299,7 @@ ENDPROC(_aesni_dec4)
* size_t len)
*/
ENTRY(aesni_ecb_enc)
+ FRAME
#ifndef __x86_64__
pushl LEN
pushl KEYP
@@ -2342,6 +2350,7 @@ ENTRY(aesni_ecb_enc)
popl KEYP
popl LEN
#endif
+ ENDFRAME
ret
ENDPROC(aesni_ecb_enc)
@@ -2350,6 +2359,7 @@ ENDPROC(aesni_ecb_enc)
* size_t len);
*/
ENTRY(aesni_ecb_dec)
+ FRAME
#ifndef __x86_64__
pushl LEN
pushl KEYP
@@ -2401,6 +2411,7 @@ ENTRY(aesni_ecb_dec)
popl KEYP
popl LEN
#endif
+ ENDFRAME
ret
ENDPROC(aesni_ecb_dec)
@@ -2409,6 +2420,7 @@ ENDPROC(aesni_ecb_dec)
* size_t len, u8 *iv)
*/
ENTRY(aesni_cbc_enc)
+ FRAME
#ifndef __x86_64__
pushl IVP
pushl LEN
@@ -2443,6 +2455,7 @@ ENTRY(aesni_cbc_enc)
popl LEN
popl IVP
#endif
+ ENDFRAME
ret
ENDPROC(aesni_cbc_enc)
@@ -2451,6 +2464,7 @@ ENDPROC(aesni_cbc_enc)
* size_t len, u8 *iv)
*/
ENTRY(aesni_cbc_dec)
+ FRAME
#ifndef __x86_64__
pushl IVP
pushl LEN
@@ -2534,6 +2548,7 @@ ENTRY(aesni_cbc_dec)
popl LEN
popl IVP
#endif
+ ENDFRAME
ret
ENDPROC(aesni_cbc_dec)
@@ -2598,6 +2613,7 @@ ENDPROC(_aesni_inc)
* size_t len, u8 *iv)
*/
ENTRY(aesni_ctr_enc)
+ FRAME
cmp $16, LEN
jb .Lctr_enc_just_ret
mov 480(KEYP), KLEN
@@ -2651,6 +2667,7 @@ ENTRY(aesni_ctr_enc)
.Lctr_enc_ret:
movups IV, (IVP)
.Lctr_enc_just_ret:
+ ENDFRAME
ret
ENDPROC(aesni_ctr_enc)
@@ -2677,6 +2694,7 @@ ENDPROC(aesni_ctr_enc)
* bool enc, u8 *iv)
*/
ENTRY(aesni_xts_crypt8)
+ FRAME
cmpb $0, %cl
movl $0, %ecx
movl $240, %r10d
@@ -2777,6 +2795,7 @@ ENTRY(aesni_xts_crypt8)
pxor INC, STATE4
movdqu STATE4, 0x70(OUTP)
+ ENDFRAME
ret
ENDPROC(aesni_xts_crypt8)
--
2.1.0
stackvalidate reports the following warning:
stackvalidate: arch/x86/crypto/aesni-intel_asm.o: _aesni_inc_init(): can't find starting instruction
stackvalidate gets confused when it tries to disassemble the following
data in the .text section:
.Lbswap_mask:
.byte 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
Move it to .rodata which is a more appropriate section for read-only
data.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/crypto/aesni-intel_asm.S | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/crypto/aesni-intel_asm.S b/arch/x86/crypto/aesni-intel_asm.S
index 3df557b..dea6cd8 100644
--- a/arch/x86/crypto/aesni-intel_asm.S
+++ b/arch/x86/crypto/aesni-intel_asm.S
@@ -2553,9 +2553,11 @@ ENTRY(aesni_cbc_dec)
ENDPROC(aesni_cbc_dec)
#ifdef __x86_64__
+.pushsection .rodata
.align 16
.Lbswap_mask:
.byte 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
+.popsection
/*
* _aesni_inc_init: internal ABI
--
2.1.0
stackvalidate reports the following warning:
stackvalidate: arch/x86/crypto/crc32c-pcl-intel-asm_64.o: crc_pcl()+0x11dd: can't decode instruction
It gets confused when trying to decode jump_table data. Move jump_table
to the .rodata section which is a more appropriate home for read-only
data.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/crypto/crc32c-pcl-intel-asm_64.S | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
index 225be06..dc05f01 100644
--- a/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
+++ b/arch/x86/crypto/crc32c-pcl-intel-asm_64.S
@@ -170,8 +170,8 @@ continue_block:
## branch into array
lea jump_table(%rip), bufp
movzxw (bufp, %rax, 2), len
- offset=crc_array-jump_table
- lea offset(bufp, len, 1), bufp
+ lea crc_array(%rip), bufp
+ lea (bufp, len, 1), bufp
jmp *bufp
################################################################
@@ -310,7 +310,9 @@ do_return:
popq %rdi
popq %rbx
ret
+ENDPROC(crc_pcl)
+.section .rodata, "a", %progbits
################################################################
## jump table Table is 129 entries x 2 bytes each
################################################################
@@ -324,13 +326,11 @@ JMPTBL_ENTRY %i
i=i+1
.endr
-ENDPROC(crc_pcl)
################################################################
## PCLMULQDQ tables
## Table is 128 entries x 2 words (8 bytes) each
################################################################
-.section .rotata, "a", %progbits
.align 8
K_table:
.long 0x493c7d27, 0x00000001
--
2.1.0
clmul_ghash_mul() and clmul_ghash_update() are callable non-leaf
functions which don't honor CONFIG_FRAME_POINTER, which can result in
bad stack traces.
Create stack frames for them when CONFIG_FRAME_POINTER is enabled.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/crypto/ghash-clmulni-intel_asm.S | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/crypto/ghash-clmulni-intel_asm.S b/arch/x86/crypto/ghash-clmulni-intel_asm.S
index 5d1e007..a5a17e6 100644
--- a/arch/x86/crypto/ghash-clmulni-intel_asm.S
+++ b/arch/x86/crypto/ghash-clmulni-intel_asm.S
@@ -18,6 +18,7 @@
#include <linux/linkage.h>
#include <asm/inst.h>
+#include <asm/frame.h>
.data
@@ -94,6 +95,7 @@ ENDPROC(__clmul_gf128mul_ble)
/* void clmul_ghash_mul(char *dst, const u128 *shash) */
ENTRY(clmul_ghash_mul)
+ FRAME
movups (%rdi), DATA
movups (%rsi), SHASH
movaps .Lbswap_mask, BSWAP
@@ -101,6 +103,7 @@ ENTRY(clmul_ghash_mul)
call __clmul_gf128mul_ble
PSHUFB_XMM BSWAP DATA
movups DATA, (%rdi)
+ ENDFRAME
ret
ENDPROC(clmul_ghash_mul)
@@ -109,6 +112,7 @@ ENDPROC(clmul_ghash_mul)
* const u128 *shash);
*/
ENTRY(clmul_ghash_update)
+ FRAME
cmp $16, %rdx
jb .Lupdate_just_ret # check length
movaps .Lbswap_mask, BSWAP
@@ -128,5 +132,6 @@ ENTRY(clmul_ghash_update)
PSHUFB_XMM BSWAP DATA
movups DATA, (%rdi)
.Lupdate_just_ret:
+ ENDFRAME
ret
ENDPROC(clmul_ghash_update)
--
2.1.0
Thunk functions are callable non-leaf functions that don't honor
CONFIG_FRAME_POINTER, which can result in bad stack traces. Also they
aren't annotated as ELF callable functions which can confuse tooling.
Create stack frames for them when CONFIG_FRAME_POINTER is enabled and
add the ELF function type.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/entry/thunk_64.S | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index efb2b93..03ee0cd 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -8,11 +8,14 @@
#include <linux/linkage.h>
#include "calling.h"
#include <asm/asm.h>
+#include <asm/frame.h>
/* rdi: arg1 ... normal C conventions. rax is saved/restored. */
.macro THUNK name, func, put_ret_addr_in_rdi=0
.globl \name
+ .type \name, @function
\name:
+ FRAME
/* this one pushes 9 elems, the next one would be %rIP */
pushq %rdi
@@ -62,6 +65,7 @@ restore:
popq %rdx
popq %rsi
popq %rdi
+ ENDFRAME
ret
_ASM_NOKPROBE(restore)
#endif
--
2.1.0
do_suspend_lowlevel() is a callable non-leaf function which doesn't
honor CONFIG_FRAME_POINTER, which can result in bad stack traces.
Create a stack frame for it when CONFIG_FRAME_POINTER is enabled.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/kernel/acpi/wakeup_64.S | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 8c35df4..7ada747 100644
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -5,6 +5,7 @@
#include <asm/page_types.h>
#include <asm/msr.h>
#include <asm/asm-offsets.h>
+#include <asm/frame.h>
# Copyright 2003 Pavel Machek <[email protected]>, distribute under GPLv2
@@ -39,6 +40,7 @@ bogus_64_magic:
jmp bogus_64_magic
ENTRY(do_suspend_lowlevel)
+ FRAME
subq $8, %rsp
xorl %eax, %eax
call save_processor_state
@@ -109,6 +111,7 @@ ENTRY(do_suspend_lowlevel)
xorl %eax, %eax
addq $8, %rsp
+ ENDFRAME
jmp restore_processor_state
ENDPROC(do_suspend_lowlevel)
--
2.1.0
rwsem.S has several callable non-leaf functions which don't honor
CONFIG_FRAME_POINTER, which can result in bad stack traces.
Create stack frames for them when CONFIG_FRAME_POINTER is enabled.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/lib/rwsem.S | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/x86/lib/rwsem.S b/arch/x86/lib/rwsem.S
index 40027db..332e533 100644
--- a/arch/x86/lib/rwsem.S
+++ b/arch/x86/lib/rwsem.S
@@ -15,6 +15,7 @@
#include <linux/linkage.h>
#include <asm/alternative-asm.h>
+#include <asm/frame.h>
#define __ASM_HALF_REG(reg) __ASM_SEL(reg, e##reg)
#define __ASM_HALF_SIZE(inst) __ASM_SEL(inst##w, inst##l)
@@ -84,24 +85,29 @@
/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
+ FRAME
save_common_regs
__ASM_SIZE(push,) %__ASM_REG(dx)
movq %rax,%rdi
call rwsem_down_read_failed
__ASM_SIZE(pop,) %__ASM_REG(dx)
restore_common_regs
+ ENDFRAME
ret
ENDPROC(call_rwsem_down_read_failed)
ENTRY(call_rwsem_down_write_failed)
+ FRAME
save_common_regs
movq %rax,%rdi
call rwsem_down_write_failed
restore_common_regs
+ ENDFRAME
ret
ENDPROC(call_rwsem_down_write_failed)
ENTRY(call_rwsem_wake)
+ FRAME
/* do nothing if still outstanding active readers */
__ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)
jnz 1f
@@ -109,15 +115,18 @@ ENTRY(call_rwsem_wake)
movq %rax,%rdi
call rwsem_wake
restore_common_regs
-1: ret
+1: ENDFRAME
+ ret
ENDPROC(call_rwsem_wake)
ENTRY(call_rwsem_downgrade_wake)
+ FRAME
save_common_regs
__ASM_SIZE(push,) %__ASM_REG(dx)
movq %rax,%rdi
call rwsem_downgrade_wake
__ASM_SIZE(pop,) %__ASM_REG(dx)
restore_common_regs
+ ENDFRAME
ret
ENDPROC(call_rwsem_downgrade_wake)
--
2.1.0
efi_call() is a callable non-leaf function which doesn't honor
CONFIG_FRAME_POINTER, which can result in bad stack traces.
Create a stack frame for it when CONFIG_FRAME_POINTER is enabled.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/platform/efi/efi_stub_64.S | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S
index 86d0f9e..fd68dea 100644
--- a/arch/x86/platform/efi/efi_stub_64.S
+++ b/arch/x86/platform/efi/efi_stub_64.S
@@ -11,6 +11,7 @@
#include <asm/msr.h>
#include <asm/processor-flags.h>
#include <asm/page_types.h>
+#include <asm/frame.h>
#define SAVE_XMM \
mov %rsp, %rax; \
@@ -74,6 +75,7 @@
.endm
ENTRY(efi_call)
+ FRAME
SAVE_XMM
mov (%rsp), %rax
mov 8(%rax), %rax
@@ -88,6 +90,7 @@ ENTRY(efi_call)
RESTORE_PGT
addq $48, %rsp
RESTORE_XMM
+ ENDFRAME
ret
ENDPROC(efi_call)
--
2.1.0
swsusp_arch_suspend() and restore_registers() are callable non-leaf
functions which don't honor CONFIG_FRAME_POINTER, which can result in
bad stack traces. Also they aren't annotated as ELF callable functions
which can confuse tooling.
Create a stack frame for them when CONFIG_FRAME_POINTER is enabled and
give them proper ELF function annotations.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/power/hibernate_asm_64.S | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index e2386cb..4d41af2 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -21,8 +21,10 @@
#include <asm/page_types.h>
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
+#include <asm/frame.h>
ENTRY(swsusp_arch_suspend)
+ FRAME
movq $saved_context, %rax
movq %rsp, pt_regs_sp(%rax)
movq %rbp, pt_regs_bp(%rax)
@@ -50,7 +52,9 @@ ENTRY(swsusp_arch_suspend)
movq %rax, restore_cr3(%rip)
call swsusp_save
+ ENDFRAME
ret
+ENDPROC(swsusp_arch_suspend)
ENTRY(restore_image)
/* switch to temporary page tables */
@@ -107,6 +111,7 @@ ENTRY(core_restore_code)
*/
ENTRY(restore_registers)
+ FRAME
/* go back to the original page tables */
movq %rbx, %cr3
@@ -147,4 +152,6 @@ ENTRY(restore_registers)
/* tell the hibernation core that we've just restored the memory */
movq %rax, in_suspend(%rip)
+ ENDFRAME
ret
+ENDPROC(restore_registers)
--
2.1.0
On Tue, Jul 28, 2015 at 7:47 AM, Josh Poimboeuf <[email protected]> wrote:
> Paravirt thunk functions aren't aligned, which can impact performance
> and is inconsistent with gcc-generated functions.
>
> Align them at 16-byte boundaries to be consistent with gcc functions.
IMO stackvalidate shouldn't warn about this. We've discussed dropping
the alignment requirement entirely, since it seems to have little
benefit on modern CPUs.
--Andy
On Tue, Jul 28, 2015 at 08:23:04AM -0700, Andy Lutomirski wrote:
> On Tue, Jul 28, 2015 at 7:47 AM, Josh Poimboeuf <[email protected]> wrote:
> > Paravirt thunk functions aren't aligned, which can impact performance
> > and is inconsistent with gcc-generated functions.
> >
> > Align them at 16-byte boundaries to be consistent with gcc functions.
>
> IMO stackvalidate shouldn't warn about this. We've discussed dropping
> the alignment requirement entirely, since it seems to have little
> benefit on modern CPUs.
Stackvalidate didn't actually find this alignment issue. I just noticed
it when fixing the frame pointer issue. If alignment no longer helps
with performance on modern CPUS, it's fine to drop this patch.
--
Josh
* Josh Poimboeuf <[email protected]> wrote:
> This is v8 of the compile-time stack validation patch set, based on the
> tip/master branch.
>
> The frame pointer macros are still called FRAME and ENDFRAME because I
> don't think we converged on anything else yet. Otherwise I tried to
> address all the other review comments from v7.
So I think:
FRAME_START
FRAME_END
would be OK.
They could be added as new aliases, keeping the old ones as well, while in the new
patches you should use this new form.
Thanks,
Ingo
On Thu, Aug 06, 2015 at 10:07:50AM +0200, Ingo Molnar wrote:
>
> * Josh Poimboeuf <[email protected]> wrote:
>
> > This is v8 of the compile-time stack validation patch set, based on the
> > tip/master branch.
> >
> > The frame pointer macros are still called FRAME and ENDFRAME because I
> > don't think we converged on anything else yet. Otherwise I tried to
> > address all the other review comments from v7.
>
> So I think:
>
> FRAME_START
> FRAME_END
>
> would be OK.
Thanks, that sounds good to me.
> They could be added as new aliases, keeping the old ones as well, while in the new
> patches you should use this new form.
Turns out nobody uses the existing FRAME/ENDFRAME macros, so I'll just
rename them.
--
Josh
On Thu, Aug 06, 2015 at 10:07:50AM +0200, Ingo Molnar wrote:
>
> * Josh Poimboeuf <[email protected]> wrote:
>
> > This is v8 of the compile-time stack validation patch set, based on the
> > tip/master branch.
> >
> > The frame pointer macros are still called FRAME and ENDFRAME because I
> > don't think we converged on anything else yet. Otherwise I tried to
> > address all the other review comments from v7.
>
> So I think:
>
> FRAME_START
> FRAME_END
(One last tweak to the bikeshed)
The antonym of END is BEGIN. So how about:
FRAME_BEGIN
FRAME_END
--
Josh
On Thu, Aug 06, 2015 at 12:23:32PM -0500, Josh Poimboeuf wrote:
> On Thu, Aug 06, 2015 at 10:07:50AM +0200, Ingo Molnar wrote:
> >
> > * Josh Poimboeuf <[email protected]> wrote:
> >
> > > This is v8 of the compile-time stack validation patch set, based on the
> > > tip/master branch.
> > >
> > > The frame pointer macros are still called FRAME and ENDFRAME because I
> > > don't think we converged on anything else yet. Otherwise I tried to
> > > address all the other review comments from v7.
> >
> > So I think:
> >
> > FRAME_START
> > FRAME_END
>
> (One last tweak to the bikeshed)
>
> The antonym of END is BEGIN. So how about:
>
> FRAME_BEGIN
> FRAME_END
Ok, so thesaurus.com reminds me that words can have more than one
antonym, and that START and BEGIN are both antonyms of END.
Personally, when I START something I usually FINISH it or even STOP it.
So I'll stop the bikeshedding I started and go with BEGIN/END.
--
Josh
Josh,
I've applied and tried to build your patchset against the latest
mainline kernel with the following config:
http://paste.ubuntu.com/12058017/
I can build if I disable CONFIG_STACK_VALIDATION, then re-enable it
after all objects are already built, so this seems like it should be
resolvable in Makefiles. Any suggestions for debugging this?
Building from clean I get the following:
~/linux$ make
HOSTCC scripts/basic/fixdep
HOSTCC scripts/basic/bin2c
GEN arch/x86/lib/inat-tables.c
HOSTCC arch/x86/tools/relocs_32.o
HOSTCC arch/x86/tools/relocs_64.o
HOSTCC arch/x86/tools/relocs_common.o
HOSTLD arch/x86/tools/relocs
CHK include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
CC arch/x86/purgatory/purgatory.o
AS arch/x86/purgatory/stack.o
AS arch/x86/purgatory/setup-x86_64.o
CC arch/x86/purgatory/sha256.o
AS arch/x86/purgatory/entry64.o
CC arch/x86/purgatory/string.o
LD arch/x86/purgatory/purgatory.ro
BIN2C arch/x86/purgatory/kexec-purgatory.c
CC kernel/bounds.s
CHK include/generated/bounds.h
CHK include/generated/timeconst.h
CC arch/x86/kernel/asm-offsets.s
CHK include/generated/asm-offsets.h
CALL scripts/checksyscalls.sh
HOSTCC scripts/genksyms/genksyms.o
HOSTCC scripts/genksyms/parse.tab.o
HOSTCC scripts/genksyms/lex.lex.o
HOSTLD scripts/genksyms/genksyms
CC scripts/mod/empty.o
scripts/mod/empty.o
open: No such file or directory
error reading elf file scripts/mod/empty.o
scripts/Makefile.build:284: recipe for target 'scripts/mod/empty.o' failed
make[2]: *** [scripts/mod/empty.o] Error 1
scripts/Makefile.build:429: recipe for target 'scripts/mod' failed
make[1]: *** [scripts/mod] Error 2
Makefile:545: recipe for target 'scripts' failed
make: *** [scripts] Error 2
On Tue, Aug 11, 2015 at 04:31:07PM -0500, Chris J Arges wrote:
> Josh,
>
> I've applied and tried to build your patchset against the latest
> mainline kernel with the following config:
> http://paste.ubuntu.com/12058017/
>
> I can build if I disable CONFIG_STACK_VALIDATION, then re-enable it
> after all objects are already built, so this seems like it should be
> resolvable in Makefiles. Any suggestions for debugging this?
>
> Building from clean I get the following:
> ~/linux$ make
> HOSTCC scripts/basic/fixdep
> HOSTCC scripts/basic/bin2c
> GEN arch/x86/lib/inat-tables.c
> HOSTCC arch/x86/tools/relocs_32.o
> HOSTCC arch/x86/tools/relocs_64.o
> HOSTCC arch/x86/tools/relocs_common.o
> HOSTLD arch/x86/tools/relocs
> CHK include/config/kernel.release
> CHK include/generated/uapi/linux/version.h
> CHK include/generated/utsrelease.h
> CC arch/x86/purgatory/purgatory.o
> AS arch/x86/purgatory/stack.o
> AS arch/x86/purgatory/setup-x86_64.o
> CC arch/x86/purgatory/sha256.o
> AS arch/x86/purgatory/entry64.o
> CC arch/x86/purgatory/string.o
> LD arch/x86/purgatory/purgatory.ro
> BIN2C arch/x86/purgatory/kexec-purgatory.c
> CC kernel/bounds.s
> CHK include/generated/bounds.h
> CHK include/generated/timeconst.h
> CC arch/x86/kernel/asm-offsets.s
> CHK include/generated/asm-offsets.h
> CALL scripts/checksyscalls.sh
> HOSTCC scripts/genksyms/genksyms.o
> HOSTCC scripts/genksyms/parse.tab.o
> HOSTCC scripts/genksyms/lex.lex.o
> HOSTLD scripts/genksyms/genksyms
> CC scripts/mod/empty.o
> scripts/mod/empty.o
> open: No such file or directory
> error reading elf file scripts/mod/empty.o
> scripts/Makefile.build:284: recipe for target 'scripts/mod/empty.o' failed
> make[2]: *** [scripts/mod/empty.o] Error 1
> scripts/Makefile.build:429: recipe for target 'scripts/mod' failed
> make[1]: *** [scripts/mod] Error 2
> Makefile:545: recipe for target 'scripts' failed
> make: *** [scripts] Error 2
Thanks for trying it out. I couldn't figure out how to recreate this
exact error, but I played around with "make mrproper" and saw some
probably related errors. Does this fix it?
---8<---
Subject: [PATCH] stackvalidate: fix circular build dependencies
After "make mrproper" with CONFIG_STACK_VALIDATION enabled, I get the
following errors:
make[2]: *** No rule to make target 'arch/x86/purgatory/purgatory.o', needed by 'arch/x86/purgatory/purgatory.ro'. Stop.
make[3]: *** No rule to make target 'scripts/mod/empty.o', needed by 'scripts/mod/elfconfig.h'. Stop.
These are caused by circular dependencies. The %.o pattern rules in
scripts/Makefile.build have the stackvalidate binary listed as a
dependency. But stackvalidate gets built *after* archprepare and
scripts/mod, both of which build objects using the %.o pattern rules.
The STACKVALIDATE and STACKVALIDATE_foo.o variables are already used to
determine whether to validate a given object. Also use them to
determine whether to create the pattern rule dependency.
Signed-off-by: Josh Poimboeuf <[email protected]>
---
scripts/Makefile.build | 7 +++++--
scripts/mod/Makefile | 2 ++
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a1270d3..ec96c51 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -243,7 +243,7 @@ endif
ifdef CONFIG_STACK_VALIDATION
-stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
+__stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
ifndef CONFIG_FRAME_POINTER
nofp = --no-frame-pointer
@@ -251,9 +251,12 @@ endif
# Set STACKVALIDATE_foo.o=n to skip stack validation for a file.
# Set STACKVALIDATE=n to skip stack validation for a directory.
+stackvalidate = $(if $(patsubst n%,, \
+ $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
+ $(__stackvalidate))
cmd_stackvalidate = $(if $(patsubst n%,, \
$(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
- $(stackvalidate) $(nofp) "$(@)";)
+ $(__stackvalidate) $(nofp) "$(@)";)
endif # CONFIG_STACK_VALIDATION
diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index c11212f..374c413 100644
--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -1,3 +1,5 @@
+STACKVALIDATE := n
+
hostprogs-y := modpost mk_elfconfig
always := $(hostprogs-y) empty.o
--
2.4.3
<snip>
>
> Thanks for trying it out. I couldn't figure out how to recreate this
> exact error, but I played around with "make mrproper" and saw some
> probably related errors. Does this fix it?
>
> ---8<---
>
> Subject: [PATCH] stackvalidate: fix circular build dependencies
>
> After "make mrproper" with CONFIG_STACK_VALIDATION enabled, I get the
> following errors:
>
> make[2]: *** No rule to make target 'arch/x86/purgatory/purgatory.o', needed by 'arch/x86/purgatory/purgatory.ro'. Stop.
> make[3]: *** No rule to make target 'scripts/mod/empty.o', needed by 'scripts/mod/elfconfig.h'. Stop.
>
> These are caused by circular dependencies. The %.o pattern rules in
> scripts/Makefile.build have the stackvalidate binary listed as a
> dependency. But stackvalidate gets built *after* archprepare and
> scripts/mod, both of which build objects using the %.o pattern rules.
>
> The STACKVALIDATE and STACKVALIDATE_foo.o variables are already used to
> determine whether to validate a given object. Also use them to
> determine whether to create the pattern rule dependency.
>
> Signed-off-by: Josh Poimboeuf <[email protected]>
> ---
> scripts/Makefile.build | 7 +++++--
> scripts/mod/Makefile | 2 ++
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index a1270d3..ec96c51 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -243,7 +243,7 @@ endif
>
> ifdef CONFIG_STACK_VALIDATION
>
> -stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
> +__stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
>
> ifndef CONFIG_FRAME_POINTER
> nofp = --no-frame-pointer
> @@ -251,9 +251,12 @@ endif
>
> # Set STACKVALIDATE_foo.o=n to skip stack validation for a file.
> # Set STACKVALIDATE=n to skip stack validation for a directory.
> +stackvalidate = $(if $(patsubst n%,, \
> + $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> + $(__stackvalidate))
> cmd_stackvalidate = $(if $(patsubst n%,, \
> $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> - $(stackvalidate) $(nofp) "$(@)";)
> + $(__stackvalidate) $(nofp) "$(@)";)
>
> endif # CONFIG_STACK_VALIDATION
>
> diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
> index c11212f..374c413 100644
> --- a/scripts/mod/Makefile
> +++ b/scripts/mod/Makefile
> @@ -1,3 +1,5 @@
> +STACKVALIDATE := n
> +
> hostprogs-y := modpost mk_elfconfig
> always := $(hostprogs-y) empty.o
>
>
Josh,
I still get build failures and I've pared it down to x86_64 defconfig plus:
CONFIG_MODVERSIONS=y
CONFIG_STACK_VALIDATION=y
And it seems like some modules may get the .tmp_foo.o treatment while
others end up foo.o so something like the following will not work:
cmd_stackvalidate = $(if $(patsubst n%,, \
$(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
$(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
In addition, I'm not sure if skipping modules like STACKVALIDATE_foo.o=n
will still function properly for modversioned modules.
I'll try to look at this more tomorrow,
--chris j arges
On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> <snip>
> >
> > Thanks for trying it out. I couldn't figure out how to recreate this
> > exact error, but I played around with "make mrproper" and saw some
> > probably related errors. Does this fix it?
> >
> > ---8<---
> >
> > Subject: [PATCH] stackvalidate: fix circular build dependencies
> >
> > After "make mrproper" with CONFIG_STACK_VALIDATION enabled, I get the
> > following errors:
> >
> > make[2]: *** No rule to make target 'arch/x86/purgatory/purgatory.o', needed by 'arch/x86/purgatory/purgatory.ro'. Stop.
> > make[3]: *** No rule to make target 'scripts/mod/empty.o', needed by 'scripts/mod/elfconfig.h'. Stop.
> >
> > These are caused by circular dependencies. The %.o pattern rules in
> > scripts/Makefile.build have the stackvalidate binary listed as a
> > dependency. But stackvalidate gets built *after* archprepare and
> > scripts/mod, both of which build objects using the %.o pattern rules.
> >
> > The STACKVALIDATE and STACKVALIDATE_foo.o variables are already used to
> > determine whether to validate a given object. Also use them to
> > determine whether to create the pattern rule dependency.
> >
> > Signed-off-by: Josh Poimboeuf <[email protected]>
> > ---
> > scripts/Makefile.build | 7 +++++--
> > scripts/mod/Makefile | 2 ++
> > 2 files changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> > index a1270d3..ec96c51 100644
> > --- a/scripts/Makefile.build
> > +++ b/scripts/Makefile.build
> > @@ -243,7 +243,7 @@ endif
> >
> > ifdef CONFIG_STACK_VALIDATION
> >
> > -stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
> > +__stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
> >
> > ifndef CONFIG_FRAME_POINTER
> > nofp = --no-frame-pointer
> > @@ -251,9 +251,12 @@ endif
> >
> > # Set STACKVALIDATE_foo.o=n to skip stack validation for a file.
> > # Set STACKVALIDATE=n to skip stack validation for a directory.
> > +stackvalidate = $(if $(patsubst n%,, \
> > + $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> > + $(__stackvalidate))
> > cmd_stackvalidate = $(if $(patsubst n%,, \
> > $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> > - $(stackvalidate) $(nofp) "$(@)";)
> > + $(__stackvalidate) $(nofp) "$(@)";)
> >
> > endif # CONFIG_STACK_VALIDATION
> >
> > diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
> > index c11212f..374c413 100644
> > --- a/scripts/mod/Makefile
> > +++ b/scripts/mod/Makefile
> > @@ -1,3 +1,5 @@
> > +STACKVALIDATE := n
> > +
> > hostprogs-y := modpost mk_elfconfig
> > always := $(hostprogs-y) empty.o
> >
> >
>
> Josh,
>
> I still get build failures and I've pared it down to x86_64 defconfig plus:
> CONFIG_MODVERSIONS=y
> CONFIG_STACK_VALIDATION=y
Are you still seeing the same error as before? I think the errors you
saw were caused by stackvalidate choking on scripts/mod/empty.o. But I
don't see how that's still possible with the above patch since I set
STACKVALIDATE to 'n' in scripts/mod/Makefile which should tell it to
skip the directory.
> And it seems like some modules may get the .tmp_foo.o treatment while
> others end up foo.o so something like the following will not work:
>
> cmd_stackvalidate = $(if $(patsubst n%,, \
> $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
>
> In addition, I'm not sure if skipping modules like STACKVALIDATE_foo.o=n
> will still function properly for modversioned modules.
I'm not sure that's really a problem, since I don't think we'll need to
skip validation of any module code. It's only used for skipping code
which runs outside of the kernel's normal operation (e.g., boot, vdso,
kexec).
--
Josh
On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> I still get build failures and I've pared it down to x86_64 defconfig plus:
> CONFIG_MODVERSIONS=y
> CONFIG_STACK_VALIDATION=y
>
> And it seems like some modules may get the .tmp_foo.o treatment while
> others end up foo.o so something like the following will not work:
>
> cmd_stackvalidate = $(if $(patsubst n%,, \
> $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
Does this fix it?
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index ec96c51..0181915 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -263,8 +263,8 @@ endif # CONFIG_STACK_VALIDATION
define rule_cc_o_c
$(call echo-cmd,checksrc) $(cmd_checksrc) \
$(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
- $(cmd_stackvalidate) \
$(cmd_modversions) \
+ $(cmd_stackvalidate) \
$(call echo-cmd,record_mcount) \
$(cmd_record_mcount) \
scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
On Thu, Aug 13, 2015 at 06:22:20AM -0500, Josh Poimboeuf wrote:
> On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> > I still get build failures and I've pared it down to x86_64 defconfig plus:
> > CONFIG_MODVERSIONS=y
> > CONFIG_STACK_VALIDATION=y
> >
> > And it seems like some modules may get the .tmp_foo.o treatment while
> > others end up foo.o so something like the following will not work:
> >
> > cmd_stackvalidate = $(if $(patsubst n%,, \
> > $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> > $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
>
> Does this fix it?
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index ec96c51..0181915 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -263,8 +263,8 @@ endif # CONFIG_STACK_VALIDATION
> define rule_cc_o_c
> $(call echo-cmd,checksrc) $(cmd_checksrc) \
> $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
> - $(cmd_stackvalidate) \
> $(cmd_modversions) \
> + $(cmd_stackvalidate) \
> $(call echo-cmd,record_mcount) \
> $(cmd_record_mcount) \
> scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
>
Josh,
Yes, this fixes my build. For completeness this is my current diff:
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a1270d3..0181915 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -243,7 +243,7 @@ endif
ifdef CONFIG_STACK_VALIDATION
-stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
+__stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
ifndef CONFIG_FRAME_POINTER
nofp = --no-frame-pointer
@@ -251,17 +251,20 @@ endif
# Set STACKVALIDATE_foo.o=n to skip stack validation for a file.
# Set STACKVALIDATE=n to skip stack validation for a directory.
+stackvalidate = $(if $(patsubst n%,, \
+ $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
+ $(__stackvalidate))
cmd_stackvalidate = $(if $(patsubst n%,, \
$(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
- $(stackvalidate) $(nofp) "$(@)";)
+ $(__stackvalidate) $(nofp) "$(@)";)
endif # CONFIG_STACK_VALIDATION
define rule_cc_o_c
$(call echo-cmd,checksrc) $(cmd_checksrc) \
$(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
- $(cmd_stackvalidate) \
$(cmd_modversions) \
+ $(cmd_stackvalidate) \
$(call echo-cmd,record_mcount) \
$(cmd_record_mcount) \
scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index c11212f..374c413 100644
--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -1,3 +1,5 @@
+STACKVALIDATE := n
+
hostprogs-y := modpost mk_elfconfig
always := $(hostprogs-y) empty.o
Thanks,
--chris
On Thu, Aug 13, 2015 at 09:42:25AM -0500, Chris J Arges wrote:
> On Thu, Aug 13, 2015 at 06:22:20AM -0500, Josh Poimboeuf wrote:
> > On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> > > I still get build failures and I've pared it down to x86_64 defconfig plus:
> > > CONFIG_MODVERSIONS=y
> > > CONFIG_STACK_VALIDATION=y
> > >
> > > And it seems like some modules may get the .tmp_foo.o treatment while
> > > others end up foo.o so something like the following will not work:
> > >
> > > cmd_stackvalidate = $(if $(patsubst n%,, \
> > > $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> > > $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
> >
> > Does this fix it?
> >
> > diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> > index ec96c51..0181915 100644
> > --- a/scripts/Makefile.build
> > +++ b/scripts/Makefile.build
> > @@ -263,8 +263,8 @@ endif # CONFIG_STACK_VALIDATION
> > define rule_cc_o_c
> > $(call echo-cmd,checksrc) $(cmd_checksrc) \
> > $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
> > - $(cmd_stackvalidate) \
> > $(cmd_modversions) \
> > + $(cmd_stackvalidate) \
> > $(call echo-cmd,record_mcount) \
> > $(cmd_record_mcount) \
> > scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
> >
>
> Josh,
>
> Yes, this fixes my build. For completeness this is my current diff:
Great! I'll roll both patches into v10.
--
Josh