Messages in this thread | | | Subject | Re: [PATCH] x86/mce: Make machine check speculation protected | Date | Fri, 19 Jan 2018 09:46:26 +0100 | From | "Woodhouse, David" <> |
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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>
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: > [unhandled content-type:application/x-pkcs7-signature] | |