3.2.81-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Borislav Petkov <b...@suse.de> commit 2eff73c0a11f19ff082a566e3429fbaaca7b8e7b upstream. Pave the way for checking the current patch level of the microcode in a core. We want to be able to do stuff depending on the patch level - in this case decide whether to update or not. But that will be added in a later patch. Drop unused local var uci assignment, while at it. Integrate a fix for 32-bit and CONFIG_PARAVIRT from Takashi Iwai: Use native_rdmsr() in check_current_patch_level() because with CONFIG_PARAVIRT enabled and on 32-bit, where we run before paging has been enabled, we cannot deref pv_info yet. Or we could, but we'd need to access its physical address. This way of fixing it is simpler. See: https://bugzilla.suse.com/show_bug.cgi?id=943179 for the background. Signed-off-by: Borislav Petkov <b...@suse.de> Cc: Borislav Petkov <b...@alien8.de> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Takashi Iwai <ti...@suse.com>: Cc: Thomas Gleixner <t...@linutronix.de> Cc: Tony Luck <tony.l...@intel.com> Link: http://lkml.kernel.org/r/1444641762-9437-6-git-send-email...@alien8.de Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Ben Hutchings <b...@decadent.org.uk> Cc: Henrique de Moraes Holschuh <h...@hmh.eng.br> --- arch/x86/include/asm/microcode.h | 1 + arch/x86/kernel/microcode_amd.c | 24 ++++++++++++++++++++++-- 3 files changed, 30 insertions(+), 12 deletions(-) --- a/arch/x86/include/asm/microcode.h +++ b/arch/x86/include/asm/microcode.h @@ -61,4 +61,5 @@ static inline struct microcode_ops * __i } #endif +extern bool check_current_patch_level(u32 *rev); #endif /* _ASM_X86_MICROCODE_H */ --- a/arch/x86/kernel/microcode_amd.c +++ b/arch/x86/kernel/microcode_amd.c @@ -123,13 +123,32 @@ static int get_matching_microcode(int cp return 1; } +/* + * 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 + * error. + * + * Returns: + * - true: if update should stop + * - false: otherwise + */ +bool check_current_patch_level(u32 *rev) +{ + u32 dummy; + + rdmsr(MSR_AMD64_PATCH_LEVEL, *rev, dummy); + + return false; +} + static int apply_microcode_amd(int cpu) { - u32 rev, dummy; int cpu_num = raw_smp_processor_id(); struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num; struct microcode_amd *mc_amd = uci->mc; struct cpuinfo_x86 *c = &cpu_data(cpu); + u32 dummy, rev; /* We should bind the task to the CPU */ BUG_ON(cpu_num != cpu); @@ -137,6 +156,9 @@ static int apply_microcode_amd(int cpu) if (mc_amd == NULL) return 0; + if (check_current_patch_level(&rev)) + return -1; + wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code); /* get patch id after patching */ rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
