2020-09-23 00:03:53

by Bill Wendling

[permalink] [raw]
Subject: [PATCH] kbuild: explicitly specify the build id style

ld's --build-id defaults to "sha1" style, while lld defaults to "fast".
The build IDs are very different between the two, which may confuse
programs that reference them.

Signed-off-by: Bill Wendling <[email protected]>
---
Makefile | 4 ++--
arch/arm/vdso/Makefile | 2 +-
arch/arm64/kernel/vdso/Makefile | 2 +-
arch/arm64/kernel/vdso32/Makefile | 2 +-
arch/mips/vdso/Makefile | 2 +-
arch/riscv/kernel/vdso/Makefile | 2 +-
arch/s390/kernel/vdso64/Makefile | 2 +-
arch/sparc/vdso/Makefile | 2 +-
arch/x86/entry/vdso/Makefile | 2 +-
tools/testing/selftests/bpf/Makefile | 2 +-
10 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index 2b66d3398878..7e6f41c9803a 100644
--- a/Makefile
+++ b/Makefile
@@ -973,8 +973,8 @@ KBUILD_CPPFLAGS += $(KCPPFLAGS)
KBUILD_AFLAGS += $(KAFLAGS)
KBUILD_CFLAGS += $(KCFLAGS)

-KBUILD_LDFLAGS_MODULE += --build-id
-LDFLAGS_vmlinux += --build-id
+KBUILD_LDFLAGS_MODULE += --build-id=sha1
+LDFLAGS_vmlinux += --build-id=sha1

ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
LDFLAGS_vmlinux += $(call ld-option, -X,)
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile
index a54f70731d9f..150ce6e6a5d3 100644
--- a/arch/arm/vdso/Makefile
+++ b/arch/arm/vdso/Makefile
@@ -19,7 +19,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO32
ldflags-$(CONFIG_CPU_ENDIAN_BE8) := --be8
ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
-z max-page-size=4096 -nostdlib -shared $(ldflags-y) \
- --hash-style=sysv --build-id \
+ --hash-style=sysv --build-id=sha1 \
-T

obj-$(CONFIG_VDSO) += vdso.o
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 45d5cfe46429..871915097f9d 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -24,7 +24,7 @@ btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti
# routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so
# preparation in build-time C")).
ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
- -Bsymbolic $(call ld-option, --no-eh-frame-hdr) --build-id -n \
+ -Bsymbolic $(call ld-option, --no-eh-frame-hdr) --build-id=sha1 -n \
$(btildflags-y) -T

ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index d6adb4677c25..4fa4b3fe8efb 100644
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -128,7 +128,7 @@ VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1
VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
VDSO_LDFLAGS += -nostdlib -shared -mfloat-abi=soft
VDSO_LDFLAGS += -Wl,--hash-style=sysv
-VDSO_LDFLAGS += -Wl,--build-id
+VDSO_LDFLAGS += -Wl,--build-id=sha1
VDSO_LDFLAGS += $(call cc32-ldoption,-fuse-ld=bfd)


diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index 57fe83235281..5810cc12bc1d 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -61,7 +61,7 @@ endif
# VDSO linker flags.
ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
$(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \
- -G 0 --eh-frame-hdr --hash-style=sysv --build-id -T
+ -G 0 --eh-frame-hdr --hash-style=sysv --build-id=sha1 -T

CFLAGS_REMOVE_vdso.o = -pg

diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 478e7338ddc1..7d6a94d45ec9 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -49,7 +49,7 @@ $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
# refer to these symbols in the kernel code rather than hand-coded addresses.

SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
- -Wl,--build-id -Wl,--hash-style=both
+ -Wl,--build-id=sha1 -Wl,--hash-style=both
$(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE
$(call if_changed,vdsold)

diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile
index 4a66a1cb919b..edc473b32e42 100644
--- a/arch/s390/kernel/vdso64/Makefile
+++ b/arch/s390/kernel/vdso64/Makefile
@@ -19,7 +19,7 @@ KBUILD_AFLAGS_64 += -m64 -s
KBUILD_CFLAGS_64 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_64 += -m64 -fPIC -shared -fno-common -fno-builtin
ldflags-y := -fPIC -shared -nostdlib -soname=linux-vdso64.so.1 \
- --hash-style=both --build-id -T
+ --hash-style=both --build-id=sha1 -T

$(targets:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_64)
$(targets:%=$(obj)/%.dbg): KBUILD_AFLAGS = $(KBUILD_AFLAGS_64)
diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile
index f44355e46f31..469dd23887ab 100644
--- a/arch/sparc/vdso/Makefile
+++ b/arch/sparc/vdso/Makefile
@@ -115,7 +115,7 @@ quiet_cmd_vdso = VDSO $@
-T $(filter %.lds,$^) $(filter %.o,$^) && \
sh $(srctree)/$(src)/checkundef.sh '$(OBJDUMP)' '$@'

-VDSO_LDFLAGS = -shared --hash-style=both --build-id -Bsymbolic
+VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 -Bsymbolic
GCOV_PROFILE := n

#
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 215376d975a2..ebba25ed9a38 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -176,7 +176,7 @@ quiet_cmd_vdso = VDSO $@
-T $(filter %.lds,$^) $(filter %.o,$^) && \
sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'

-VDSO_LDFLAGS = -shared --hash-style=both --build-id \
+VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \
$(call ld-option, --eh-frame-hdr) -Bsymbolic
GCOV_PROFILE := n

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index fc946b7ac288..daf186f88a63 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -133,7 +133,7 @@ $(OUTPUT)/%:%.c

$(OUTPUT)/urandom_read: urandom_read.c
$(call msg,BINARY,,$@)
- $(Q)$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS) -Wl,--build-id
+ $(Q)$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS) -Wl,--build-id=sha1

$(OUTPUT)/test_stub.o: test_stub.c $(BPFOBJ)
$(call msg,CC,,$@)
--
2.28.0.681.g6f77f65b4e-goog


2020-09-23 00:06:05

by David Miller

[permalink] [raw]
Subject: Re: [PATCH] kbuild: explicitly specify the build id style

From: Bill Wendling <[email protected]>
Date: Tue, 22 Sep 2020 16:21:40 -0700

> ld's --build-id defaults to "sha1" style, while lld defaults to "fast".
> The build IDs are very different between the two, which may confuse
> programs that reference them.
>
> Signed-off-by: Bill Wendling <[email protected]>

Acked-by: David S. Miller <[email protected]>

2020-09-24 16:08:16

by Masahiro Yamada

[permalink] [raw]
Subject: Re: [PATCH] kbuild: explicitly specify the build id style

On Wed, Sep 23, 2020 at 8:21 AM Bill Wendling <[email protected]> wrote:
>
> ld's --build-id defaults to "sha1" style, while lld defaults to "fast".
> The build IDs are very different between the two, which may confuse
> programs that reference them.
>
> Signed-off-by: Bill Wendling <[email protected]>
> ---
> Makefile | 4 ++--
> arch/arm/vdso/Makefile | 2 +-
> arch/arm64/kernel/vdso/Makefile | 2 +-
> arch/arm64/kernel/vdso32/Makefile | 2 +-
> arch/mips/vdso/Makefile | 2 +-
> arch/riscv/kernel/vdso/Makefile | 2 +-
> arch/s390/kernel/vdso64/Makefile | 2 +-
> arch/sparc/vdso/Makefile | 2 +-
> arch/x86/entry/vdso/Makefile | 2 +-
> tools/testing/selftests/bpf/Makefile | 2 +-
> 10 files changed, 11 insertions(+), 11 deletions(-)


Applied to linux-kbuild.
Thanks.

--
Best Regards
Masahiro Yamada