From c5aa687060a85d849574ad014639f93b1dc98ea0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 18 Jan 2018 16:28:26 +0100 Subject: 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: Thomas Gleixner Reviewed-by:Borislav Petkov Reviewed-by: David Woodhouse Niced-by: Peter Zijlstra Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801181626290.1847@nanos Signed-off-by: Greg Kroah-Hartman --- 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(-) (limited to 'arch') diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3a15023bdf1a..e729e1528584 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -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 /* diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 01fd0a7f48cd..688315b7a922 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -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) { diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 8ca5f8ad008e..fe5cd6ea1f0e 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -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: -- cgit v1.2.3