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x86/mce: Make machine check speculation protected

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commit 6f41c34d69eb005e7848716bbcafc979b35037d5 upstream.

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>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801181626290.1847@nanos
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Gleixner 2018-01-18 16:28:26 +01:00 committed by Greg Kroah-Hartman
parent 87ac29717d
commit c5aa687060
3 changed files with 7 additions and 1 deletions
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2
arch/x86/entry/entry_64.S
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@ -1064,7 +1064,7 @@ 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
/*

1
arch/x86/include/asm/traps.h
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@ -92,6 +92,7 @@ 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)
{

5
arch/x86/kernel/cpu/mcheck/mce.c
View File

@ -1754,6 +1754,11 @@ 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: