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Commit 020c755f authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman
Browse files

x86/mce: Make machine check speculation protected 



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: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@alien8.de>
Reviewed-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Niced-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801181626290.1847@nanos


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 14c7f5bc

arch/x86/entry/entry_64.S

+1 −1
Original line number Diff line number Diff line
@@ -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



/*

arch/x86/include/asm/traps.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

{

arch/x86/kernel/cpu/mcheck/mce.c

+5 −0
Original line number Diff line number Diff line
@@ -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: