* Re: [PATCH] x86/mce: Make machine check speculation protected
2018-01-18 15:28 [PATCH] x86/mce: Make machine check speculation protected Thomas Gleixner
@ 2018-01-18 15:46 ` Peter Zijlstra
2018-01-18 15:53 ` Borislav Petkov
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Peter Zijlstra @ 2018-01-18 15:46 UTC (permalink / raw)
To: Thomas Gleixner; +Cc: LKML, x86, Borislav Petkov, David Woodhouse
On Thu, Jan 18, 2018 at 04:28:26PM +0100, Thomas Gleixner wrote:
> The machine check idtentry uses an indirect branch directly from the low
> level code. This evades the speculation protection.
>
> Replace it by a direct call into C code and issue the indirect call there
> so the compiler can apply the proper speculation protection.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/entry/entry_64.S | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/kernel/cpu/mcheck/mce.c | 5 +++++
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -1264,7 +1264,7 @@ idtentry async_page_fault do_async_page_
> #endif
>
> #ifdef CONFIG_X86_MCE
> -idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip)
> +idtentry machine_check do_mce has_error_code=0 paranoid=1
Nice, Thanks!
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] x86/mce: Make machine check speculation protected
2018-01-18 15:28 [PATCH] x86/mce: Make machine check speculation protected Thomas Gleixner
2018-01-18 15:46 ` Peter Zijlstra
@ 2018-01-18 15:53 ` Borislav Petkov
2018-01-18 15:55 ` David Woodhouse
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Borislav Petkov @ 2018-01-18 15:53 UTC (permalink / raw)
To: Thomas Gleixner; +Cc: LKML, x86, Peter Zijlstra, David Woodhouse
On Thu, Jan 18, 2018 at 04:28:26PM +0100, Thomas Gleixner wrote:
> The machine check idtentry uses an indirect branch directly from the low
> level code. This evades the speculation protection.
>
> Replace it by a direct call into C code and issue the indirect call there
> so the compiler can apply the proper speculation protection.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/entry/entry_64.S | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/kernel/cpu/mcheck/mce.c | 5 +++++
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -1264,7 +1264,7 @@ idtentry async_page_fault do_async_page_
> #endif
>
> #ifdef CONFIG_X86_MCE
> -idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip)
> +idtentry machine_check do_mce has_error_code=0 paranoid=1
> #endif
>
> /*
> --- a/arch/x86/include/asm/traps.h
> +++ b/arch/x86/include/asm/traps.h
> @@ -88,6 +88,7 @@ dotraplinkage void do_simd_coprocessor_e
> #ifdef CONFIG_X86_32
> dotraplinkage void do_iret_error(struct pt_regs *, long);
> #endif
> +dotraplinkage void do_mce(struct pt_regs *, long);
>
> static inline int get_si_code(unsigned long condition)
> {
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1785,6 +1785,11 @@ static void unexpected_machine_check(str
> void (*machine_check_vector)(struct pt_regs *, long error_code) =
> unexpected_machine_check;
>
> +dotraplinkage void do_mce(struct pt_regs *regs, long error_code)
> +{
> + machine_check_vector(regs, error_code);
> +}
> +
> /*
> * Called for each booted CPU to set up machine checks.
> * Must be called with preempt off:
Reviewed-by: Borislav Petkov <bp@suse.de>
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] x86/mce: Make machine check speculation protected
2018-01-18 15:28 [PATCH] x86/mce: Make machine check speculation protected Thomas Gleixner
2018-01-18 15:46 ` Peter Zijlstra
2018-01-18 15:53 ` Borislav Petkov
@ 2018-01-18 15:55 ` David Woodhouse
2018-01-19 8:46 ` Woodhouse, David
2018-01-19 15:46 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
4 siblings, 0 replies; 6+ messages in thread
From: David Woodhouse @ 2018-01-18 15:55 UTC (permalink / raw)
To: Thomas Gleixner, LKML; +Cc: x86, Peter Zijlstra, Borislav Petkov
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On Thu, 2018-01-18 at 16:28 +0100, Thomas Gleixner wrote:
> The machine check idtentry uses an indirect branch directly from the low
> level code. This evades the speculation protection.
>
> Replace it by a direct call into C code and issue the indirect call there
> so the compiler can apply the proper speculation protection.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86/mce: Make machine check speculation protected
2018-01-18 15:28 [PATCH] x86/mce: Make machine check speculation protected Thomas Gleixner
` (2 preceding siblings ...)
2018-01-18 15:55 ` David Woodhouse
@ 2018-01-19 8:46 ` Woodhouse, David
2018-01-19 15:46 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
4 siblings, 0 replies; 6+ messages in thread
From: Woodhouse, David @ 2018-01-19 8:46 UTC (permalink / raw)
To: Thomas Gleixner, LKML
Cc: x86, Peter Zijlstra, Borislav Petkov, stable, Ghitulete, Razvan-alin
[-- Attachment #1: Type: text/plain, Size: 1904 bytes --]
On Thu, 2018-01-18 at 16:28 +0100, Thomas Gleixner wrote:
> The machine check idtentry uses an indirect branch directly from the low
> level code. This evades the speculation protection.
>
> Replace it by a direct call into C code and issue the indirect call there
> so the compiler can apply the proper speculation protection.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable for at least 4.9.
> ---
> arch/x86/entry/entry_64.S | 2 +-
> arch/x86/include/asm/traps.h | 1 +
> arch/x86/kernel/cpu/mcheck/mce.c | 5 +++++
> 3 files changed, 7 insertions(+), 1 deletion(-)
>
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -1264,7 +1264,7 @@ idtentry async_page_fault do_async_page_
> #endif
>
> #ifdef CONFIG_X86_MCE
> -idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip)
> +idtentry machine_check do_mce has_error_code=0 paranoid=1
> #endif
>
> /*
> --- a/arch/x86/include/asm/traps.h
> +++ b/arch/x86/include/asm/traps.h
> @@ -88,6 +88,7 @@ dotraplinkage void do_simd_coprocessor_e
> #ifdef CONFIG_X86_32
> dotraplinkage void do_iret_error(struct pt_regs *, long);
> #endif
> +dotraplinkage void do_mce(struct pt_regs *, long);
>
> static inline int get_si_code(unsigned long condition)
> {
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1785,6 +1785,11 @@ static void unexpected_machine_check(str
> void (*machine_check_vector)(struct pt_regs *, long error_code) =
> unexpected_machine_check;
>
> +dotraplinkage void do_mce(struct pt_regs *regs, long error_code)
> +{
> + machine_check_vector(regs, error_code);
> +}
> +
> /*
> * Called for each booted CPU to set up machine checks.
> * Must be called with preempt off:
>
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^ permalink raw reply [flat|nested] 6+ messages in thread* [tip:x86/pti] x86/mce: Make machine check speculation protected
2018-01-18 15:28 [PATCH] x86/mce: Make machine check speculation protected Thomas Gleixner
` (3 preceding siblings ...)
2018-01-19 8:46 ` Woodhouse, David
@ 2018-01-19 15:46 ` tip-bot for Thomas Gleixner
4 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Thomas Gleixner @ 2018-01-19 15:46 UTC (permalink / raw)
To: linux-tip-commits; +Cc: mingo, dwmw, linux-kernel, tglx, peterz, hpa
Commit-ID: 6f41c34d69eb005e7848716bbcafc979b35037d5
Gitweb: https://git.kernel.org/tip/6f41c34d69eb005e7848716bbcafc979b35037d5
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 18 Jan 2018 16:28:26 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 19 Jan 2018 16:31:28 +0100
x86/mce: Make machine check speculation protected
The machine check idtentry uses an indirect branch directly from the low
level code. This evades the speculation protection.
Replace it by a direct call into C code and issue the indirect call there
so the compiler can apply the proper speculation protection.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by:Borislav Petkov <bp@alien8.de>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Niced-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801181626290.1847@nanos
---
arch/x86/entry/entry_64.S | 2 +-
arch/x86/include/asm/traps.h | 1 +
arch/x86/kernel/cpu/mcheck/mce.c | 5 +++++
3 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index d54a0ed..63f4320 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1258,7 +1258,7 @@ idtentry async_page_fault do_async_page_fault has_error_code=1
#endif
#ifdef CONFIG_X86_MCE
-idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip)
+idtentry machine_check do_mce has_error_code=0 paranoid=1
#endif
/*
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 31051f3..3de6933 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -88,6 +88,7 @@ dotraplinkage void do_simd_coprocessor_error(struct pt_regs *, long);
#ifdef CONFIG_X86_32
dotraplinkage void do_iret_error(struct pt_regs *, long);
#endif
+dotraplinkage void do_mce(struct pt_regs *, long);
static inline int get_si_code(unsigned long condition)
{
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 3b413065..a9e898b 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1788,6 +1788,11 @@ static void unexpected_machine_check(struct pt_regs *regs, long error_code)
void (*machine_check_vector)(struct pt_regs *, long error_code) =
unexpected_machine_check;
+dotraplinkage void do_mce(struct pt_regs *regs, long error_code)
+{
+ machine_check_vector(regs, error_code);
+}
+
/*
* Called for each booted CPU to set up machine checks.
* Must be called with preempt off:
^ permalink raw reply [flat|nested] 6+ messages in thread