From: Kan Liang kan.liang@linux.intel.com
For bug workarounds or checks, it is useful to check for specific microcode revisions.
Add a new generic function to match the CPU with stepping. Add the other function to check the min microcode revisions for the matched CPU.
A new table format is introduced to facilitate the quirk to fill the related information.
This does not change the existing x86_cpu_id because it's an ABI shared with modules, and also has quite different requirements, as in no wildcards, but everything has to be matched exactly.
Originally-by: Andi Kleen ak@linux.intel.com Suggested-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Kan Liang kan.liang@linux.intel.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Acked-by: Borislav Petkov bp@alien8.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: eranian@google.com Link: https://lkml.kernel.org/r/1549319013-4522-1-git-send-email-kan.liang@linux.i... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Suleiman Souhlal suleiman@google.com --- arch/x86/include/asm/cpu_device_id.h | 28 +++++++++++++++++++++++++ arch/x86/kernel/cpu/match.c | 31 ++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+)
diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h index baeba0567126..3417110574c1 100644 --- a/arch/x86/include/asm/cpu_device_id.h +++ b/arch/x86/include/asm/cpu_device_id.h @@ -11,4 +11,32 @@
extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
+/* + * Match specific microcode revisions. + * + * vendor/family/model/stepping must be all set. + * + * Only checks against the boot CPU. When mixed-stepping configs are + * valid for a CPU model, add a quirk for every valid stepping and + * do the fine-tuning in the quirk handler. + */ + +struct x86_cpu_desc { + __u8 x86_family; + __u8 x86_vendor; + __u8 x86_model; + __u8 x86_stepping; + __u32 x86_microcode_rev; +}; + +#define INTEL_CPU_DESC(mod, step, rev) { \ + .x86_family = 6, \ + .x86_vendor = X86_VENDOR_INTEL, \ + .x86_model = mod, \ + .x86_stepping = step, \ + .x86_microcode_rev = rev, \ +} + +extern bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table); + #endif diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c index 3fed38812eea..6dd78d8235e4 100644 --- a/arch/x86/kernel/cpu/match.c +++ b/arch/x86/kernel/cpu/match.c @@ -48,3 +48,34 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match) return NULL; } EXPORT_SYMBOL(x86_match_cpu); + +static const struct x86_cpu_desc * +x86_match_cpu_with_stepping(const struct x86_cpu_desc *match) +{ + struct cpuinfo_x86 *c = &boot_cpu_data; + const struct x86_cpu_desc *m; + + for (m = match; m->x86_family | m->x86_model; m++) { + if (c->x86_vendor != m->x86_vendor) + continue; + if (c->x86 != m->x86_family) + continue; + if (c->x86_model != m->x86_model) + continue; + if (c->x86_stepping != m->x86_stepping) + continue; + return m; + } + return NULL; +} + +bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table) +{ + const struct x86_cpu_desc *res = x86_match_cpu_with_stepping(table); + + if (!res || res->x86_microcode_rev > boot_cpu_data.microcode) + return false; + + return true; +} +EXPORT_SYMBOL_GPL(x86_cpu_has_min_microcode_rev);