3.16.55-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner <[email 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 <[email protected]> Reviewed-by:Borislav Petkov <[email protected]> Reviewed-by: David Woodhouse <[email protected]> Niced-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801181626290.1847@nanos [bwh: Backported to 3.16 - #include <asm/traps.h> in mce.c - Adjust filename, context] Signed-off-by: Ben Hutchings <[email protected]> --- --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -91,6 +91,7 @@ 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 @@ -46,6 +46,7 @@ #include <asm/tlbflush.h> #include <asm/mce.h> #include <asm/msr.h> +#include <asm/traps.h> #include "mce-internal.h" @@ -1693,6 +1694,11 @@ 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: --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1320,7 +1320,7 @@ trace_idtentry page_fault do_page_fault 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 /*
