From: Thomas Gleixner <[email protected]>
Convert the IRET exception handler to IDTENTRY_SW. This is slightly
different than the conversions of hardware exceptions as the IRET exception
is invoked via an exception table when IRET faults. So it just uses the
IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does
not fit the other idtentry exceptions.
- Implement the C entry point with DEFINE_IDTENTRY_SW() which maps to
DEFINE_IDTENTRY()
- Fixup the XEN/PV code
- Remove the old prototyoes
- Remove the RCU warning as the new entry macro ensures correctness
No functional change.
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/x86/entry/entry_32.S | 14 +++++++-------
arch/x86/include/asm/idtentry.h | 10 ++++++++++
arch/x86/include/asm/traps.h | 3 ---
arch/x86/kernel/traps.c | 8 +++-----
arch/x86/xen/xen-asm_32.S | 2 +-
5 files changed, 21 insertions(+), 16 deletions(-)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1147,9 +1147,9 @@ SYM_FUNC_START(entry_INT80_32)
jmp .Lirq_return
.section .fixup, "ax"
-SYM_CODE_START(iret_exc)
+SYM_CODE_START(asm_exc_iret_error)
pushl $0 # no error code
- pushl $do_iret_error
+ pushl $exc_iret_error
#ifdef CONFIG_DEBUG_ENTRY
/*
@@ -1163,10 +1163,10 @@ SYM_CODE_START(iret_exc)
popl %eax
#endif
- jmp common_exception
-SYM_CODE_END(iret_exc)
+ jmp handle_exception
+SYM_CODE_END(asm_exc_iret_error)
.previous
- _ASM_EXTABLE(.Lirq_return, iret_exc)
+ _ASM_EXTABLE(.Lirq_return, asm_exc_iret_error)
SYM_FUNC_END(entry_INT80_32)
.macro FIXUP_ESPFIX_STACK
@@ -1293,7 +1293,7 @@ SYM_FUNC_END(name)
#ifdef CONFIG_PARAVIRT
SYM_CODE_START(native_iret)
iret
- _ASM_EXTABLE(native_iret, iret_exc)
+ _ASM_EXTABLE(native_iret, asm_exc_iret_error)
SYM_CODE_END(native_iret)
#endif
@@ -1358,7 +1358,7 @@ SYM_FUNC_START(xen_failsafe_callback)
popl %eax
lea 16(%esp), %esp
jz 5f
- jmp iret_exc
+ jmp asm_exc_iret_error
5: pushl $-1 /* orig_ax = -1 => not a system call */
SAVE_ALL
ENCODE_FRAME_POINTER
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -57,6 +57,10 @@ static __always_inline void __##func(str
\
static __always_inline void __##func(struct pt_regs *regs)
+/* Special case for 32bit IRET 'trap' */
+#define DECLARE_IDTENTRY_SW DECLARE_IDTENTRY
+#define DEFINE_IDTENTRY_SW DEFINE_IDTENTRY
+
/**
* DECLARE_IDTENTRY_ERRORCODE - Declare functions for simple IDT entry points
* Error code pushed by hardware
@@ -111,6 +115,9 @@ static __always_inline void __##func(str
#define DECLARE_IDTENTRY_ERRORCODE(vector, func) \
idtentry vector asm_##func func has_error_code=1 sane=1
+/* Special case for 32bit IRET 'trap'. Do not emit ASM code */
+#define DECLARE_IDTENTRY_SW(vector, func)
+
#endif /* __ASSEMBLY__ */
/*
@@ -133,6 +140,9 @@ DECLARE_IDTENTRY(X86_TRAP_SPURIOUS, exc_
DECLARE_IDTENTRY(X86_TRAP_MF, exc_coprocessor_error);
DECLARE_IDTENTRY(X86_TRAP_XF, exc_simd_coprocessor_error);
+/* 32bit software IRET trap. Do not emit ASM code */
+DECLARE_IDTENTRY_SW(X86_TRAP_IRET, exc_iret_error);
+
/* Simple exception entries with error code pushed by hardware */
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_TS, exc_invalid_tss);
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_NP, exc_segment_not_present);
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -41,9 +41,6 @@ dotraplinkage void do_int3(struct pt_reg
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
#endif
dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
-#ifdef CONFIG_X86_32
-dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code);
-#endif
dotraplinkage void do_mce(struct pt_regs *regs, long error_code);
#ifdef CONFIG_X86_64
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -917,14 +917,12 @@ DEFINE_IDTENTRY(exc_device_not_available
}
#ifdef CONFIG_X86_32
-dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY_SW(exc_iret_error)
{
- RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
local_irq_enable();
-
- if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
+ if (notify_die(DIE_TRAP, "iret exception", regs, 0,
X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
- do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
+ do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, 0,
ILL_BADSTK, (void __user *)NULL);
}
local_irq_disable();
--- a/arch/x86/xen/xen-asm_32.S
+++ b/arch/x86/xen/xen-asm_32.S
@@ -117,7 +117,7 @@ SYM_CODE_START(xen_iret)
1: iret
xen_iret_end_crit:
- _ASM_EXTABLE(1b, iret_exc)
+ _ASM_EXTABLE(1b, asm_exc_iret_error)
hyper_iret:
/* put this out of line since its very rarely used */
On 5/5/20 3:44 PM, Thomas Gleixner wrote:
> From: Thomas Gleixner <[email protected]>
>
> Convert the IRET exception handler to IDTENTRY_SW. This is slightly
> different than the conversions of hardware exceptions as the IRET exception
> is invoked via an exception table when IRET faults. So it just uses the
> IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does
> not fit the other idtentry exceptions.
>
> - Implement the C entry point with DEFINE_IDTENTRY_SW() which maps to
> DEFINE_IDTENTRY()
> - Fixup the XEN/PV code
> - Remove the old prototyoes
> - Remove the RCU warning as the new entry macro ensures correctness
>
> No functional change.
>
> Signed-off-by: Thomas Gleixner <[email protected]>
>
For all patches of part 3:
Reviewed-by: Alexandre Chartre <[email protected]>
alex
On Tue, May 5, 2020 at 7:15 AM Thomas Gleixner <[email protected]> wrote:
>
> From: Thomas Gleixner <[email protected]>
>
> Convert the IRET exception handler to IDTENTRY_SW. This is slightly
> different than the conversions of hardware exceptions as the IRET exception
> is invoked via an exception table when IRET faults. So it just uses the
> IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does
> not fit the other idtentry exceptions.
Blech. I should redo the 32-bit code to handle this the way the
64-bit code does and this can all be deleted. But, for now:
Acked-by: Andy Lutomirski <[email protected]>
However, maybe rename asm_exc_iret_error to avoid confusion? It's not
really an exception entry.
Andy Lutomirski <[email protected]> writes:
> On Tue, May 5, 2020 at 7:15 AM Thomas Gleixner <[email protected]> wrote:
>>
>> From: Thomas Gleixner <[email protected]>
>>
>> Convert the IRET exception handler to IDTENTRY_SW. This is slightly
>> different than the conversions of hardware exceptions as the IRET exception
>> is invoked via an exception table when IRET faults. So it just uses the
>> IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does
>> not fit the other idtentry exceptions.
>
> Blech. I should redo the 32-bit code to handle this the way the
> 64-bit code does and this can all be deleted. But, for now:
>
> Acked-by: Andy Lutomirski <[email protected]>
>
> However, maybe rename asm_exc_iret_error to avoid confusion? It's not
> really an exception entry.
True. Removed the 'exc_' from all instances.
The following commit has been merged into the x86/entry branch of tip:
Commit-ID: db300565d865092ee8a372a6bd15eb2764ec85ab
Gitweb: https://git.kernel.org/tip/db300565d865092ee8a372a6bd15eb2764ec85ab
Author: Thomas Gleixner <[email protected]>
AuthorDate: Tue, 25 Feb 2020 23:16:30 +01:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Tue, 19 May 2020 16:04:04 +02:00
x86/entry/32: Convert IRET exception to IDTENTRY_SW
Convert the IRET exception handler to IDTENTRY_SW. This is slightly
different than the conversions of hardware exceptions as the IRET exception
is invoked via an exception table when IRET faults. So it just uses the
IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does
not fit the other idtentry exceptions.
- Implement the C entry point with DEFINE_IDTENTRY_SW() which maps to
DEFINE_IDTENTRY()
- Fixup the XEN/PV code
- Remove the old prototypes
- Remove the RCU warning as the new entry macro ensures correctness
No functional change.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/entry/entry_32.S | 14 +++++++-------
arch/x86/include/asm/idtentry.h | 10 ++++++++++
arch/x86/include/asm/traps.h | 3 ---
arch/x86/kernel/traps.c | 8 +++-----
arch/x86/xen/xen-asm_32.S | 2 +-
5 files changed, 21 insertions(+), 16 deletions(-)
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index c93fb73..f7a5f1c 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1147,9 +1147,9 @@ restore_all_kernel:
jmp .Lirq_return
.section .fixup, "ax"
-SYM_CODE_START(iret_exc)
+SYM_CODE_START(asm_iret_error)
pushl $0 # no error code
- pushl $do_iret_error
+ pushl $iret_error
#ifdef CONFIG_DEBUG_ENTRY
/*
@@ -1163,10 +1163,10 @@ SYM_CODE_START(iret_exc)
popl %eax
#endif
- jmp common_exception
-SYM_CODE_END(iret_exc)
+ jmp handle_exception
+SYM_CODE_END(asm_iret_error)
.previous
- _ASM_EXTABLE(.Lirq_return, iret_exc)
+ _ASM_EXTABLE(.Lirq_return, asm_iret_error)
SYM_FUNC_END(entry_INT80_32)
.macro FIXUP_ESPFIX_STACK
@@ -1293,7 +1293,7 @@ SYM_FUNC_END(name)
#ifdef CONFIG_PARAVIRT
SYM_CODE_START(native_iret)
iret
- _ASM_EXTABLE(native_iret, iret_exc)
+ _ASM_EXTABLE(native_iret, asm_iret_error)
SYM_CODE_END(native_iret)
#endif
@@ -1358,7 +1358,7 @@ SYM_FUNC_START(xen_failsafe_callback)
popl %eax
lea 16(%esp), %esp
jz 5f
- jmp iret_exc
+ jmp asm_iret_error
5: pushl $-1 /* orig_ax = -1 => not a system call */
SAVE_ALL
ENCODE_FRAME_POINTER
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 99d4759..ee6ebfe 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -57,6 +57,10 @@ __visible noinstr void func(struct pt_regs *regs) \
\
static __always_inline void __##func(struct pt_regs *regs)
+/* Special case for 32bit IRET 'trap' */
+#define DECLARE_IDTENTRY_SW DECLARE_IDTENTRY
+#define DEFINE_IDTENTRY_SW DEFINE_IDTENTRY
+
/**
* DECLARE_IDTENTRY_ERRORCODE - Declare functions for simple IDT entry points
* Error code pushed by hardware
@@ -111,6 +115,9 @@ static __always_inline void __##func(struct pt_regs *regs, \
#define DECLARE_IDTENTRY_ERRORCODE(vector, func) \
idtentry vector asm_##func func has_error_code=1 sane=1
+/* Special case for 32bit IRET 'trap'. Do not emit ASM code */
+#define DECLARE_IDTENTRY_SW(vector, func)
+
#endif /* __ASSEMBLY__ */
/*
@@ -133,6 +140,9 @@ DECLARE_IDTENTRY(X86_TRAP_SPURIOUS, exc_spurious_interrupt_bug);
DECLARE_IDTENTRY(X86_TRAP_MF, exc_coprocessor_error);
DECLARE_IDTENTRY(X86_TRAP_XF, exc_simd_coprocessor_error);
+/* 32bit software IRET trap. Do not emit ASM code */
+DECLARE_IDTENTRY_SW(X86_TRAP_IRET, iret_error);
+
/* Simple exception entries with error code pushed by hardware */
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_TS, exc_invalid_tss);
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_NP, exc_segment_not_present);
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index e7eb753..5774d0b 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -39,9 +39,6 @@ dotraplinkage void do_nmi(struct pt_regs *regs, long error_code);
dotraplinkage void do_int3(struct pt_regs *regs, long error_code);
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
-#ifdef CONFIG_X86_32
-dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code);
-#endif
dotraplinkage void do_mce(struct pt_regs *regs, long error_code);
#ifdef CONFIG_X86_64
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 1702922..b28a64d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -925,14 +925,12 @@ DEFINE_IDTENTRY(exc_device_not_available)
}
#ifdef CONFIG_X86_32
-dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
+DEFINE_IDTENTRY_SW(iret_error)
{
- RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
local_irq_enable();
-
- if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
+ if (notify_die(DIE_TRAP, "iret exception", regs, 0,
X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
- do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
+ do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, 0,
ILL_BADSTK, (void __user *)NULL);
}
local_irq_disable();
diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S
index 2712e91..812ff01 100644
--- a/arch/x86/xen/xen-asm_32.S
+++ b/arch/x86/xen/xen-asm_32.S
@@ -117,7 +117,7 @@ iret_restore_end:
1: iret
xen_iret_end_crit:
- _ASM_EXTABLE(1b, iret_exc)
+ _ASM_EXTABLE(1b, asm_iret_error)
hyper_iret:
/* put this out of line since its very rarely used */