3.2.81-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Borislav Petkov <[email protected]> commit 0399f73299f1b7e04de329050f7111b362b7eeb5 upstream. A certain number of patch levels of applied microcode should not be overwritten by the microcode loader, otherwise bad things will happen. Check those and abort update if the current core has one of those final patch levels applied by the BIOS. 32-bit needs special handling, of course. See https://bugzilla.suse.com/show_bug.cgi?id=913996 for more info. Tested-by: Peter Kirchgeßner <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Luck <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> Cc: Henrique de Moraes Holschuh <[email protected]> --- arch/x86/include/asm/microcode.h | 2 +- arch/x86/kernel/cpu/microcode/amd.c | 38 +++++++++++++++++++++++++++---- arch/x86/kernel/cpu/microcode/amd_early.c | 13 ++++++++--- 3 files changed, 44 insertions(+), 9 deletions(-) --- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -61,5 +61,5 @@ static inline struct microcode_ops * __i } #endif -extern bool check_current_patch_level(u32 *rev); +extern bool check_current_patch_level(u32 *rev, bool early); #endif /* _ASM_X86_MICROCODE_H */ --- a/arch/x86/kernel/microcode_amd.c +++ b/arch/x86/kernel/microcode_amd.c @@ -124,6 +124,16 @@ static int get_matching_microcode(int cp } /* + * Those patch levels cannot be updated to newer ones and thus should be final. + */ +static u32 final_levels[] = { + 0x01000098, + 0x0100009f, + 0x010000af, + 0, /* T-101 terminator */ +}; + +/* * Check the current patch level on this CPU. * * @rev: Use it to return the patch level. It is set to 0 in the case of @@ -133,13 +143,33 @@ static int get_matching_microcode(int cp * - true: if update should stop * - false: otherwise */ -bool check_current_patch_level(u32 *rev) +bool check_current_patch_level(u32 *rev, bool early) { - u32 dummy; + u32 lvl, dummy, i; + bool ret = false; + u32 *levels; + + rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy); + +#ifdef CONFIG_X86_32 + if (early) + levels = (u32 *)__pa_nodebug(&final_levels); + else +#endif + levels = final_levels; + + for (i = 0; levels[i]; i++) { + if (lvl == levels[i]) { + lvl = 0; + ret = true; + break; + } + } - rdmsr(MSR_AMD64_PATCH_LEVEL, *rev, dummy); + if (rev) + *rev = lvl; - return false; + return ret; } static int apply_microcode_amd(int cpu) @@ -156,7 +186,7 @@ static int apply_microcode_amd(int cpu) if (mc_amd == NULL) return 0; - if (check_current_patch_level(&rev)) + if (check_current_patch_level(&rev, false)) return -1; wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code);
