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https://github.com/torvalds/linux
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0f42b790c9
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.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
82 lines
2.4 KiB
C
82 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <asm/cpu_device_id.h>
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#include <asm/cpufeature.h>
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#include <linux/cpu.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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/**
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* x86_match_cpu - match current CPU again an array of x86_cpu_ids
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* @match: Pointer to array of x86_cpu_ids. Last entry terminated with
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* {}.
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*
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* Return the entry if the current CPU matches the entries in the
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* passed x86_cpu_id match table. Otherwise NULL. The match table
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* contains vendor (X86_VENDOR_*), family, model and feature bits or
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* respective wildcard entries.
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*
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* A typical table entry would be to match a specific CPU
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* { X86_VENDOR_INTEL, 6, 0x12 }
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* or to match a specific CPU feature
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* { X86_FEATURE_MATCH(X86_FEATURE_FOOBAR) }
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*
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* Fields can be wildcarded with %X86_VENDOR_ANY, %X86_FAMILY_ANY,
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* %X86_MODEL_ANY, %X86_FEATURE_ANY or 0 (except for vendor)
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*
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* Arrays used to match for this should also be declared using
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* MODULE_DEVICE_TABLE(x86cpu, ...)
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*
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* This always matches against the boot cpu, assuming models and features are
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* consistent over all CPUs.
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*/
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const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
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{
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const struct x86_cpu_id *m;
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struct cpuinfo_x86 *c = &boot_cpu_data;
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for (m = match; m->vendor | m->family | m->model | m->feature; m++) {
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if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
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continue;
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if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
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continue;
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if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
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continue;
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if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
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continue;
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return m;
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}
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return NULL;
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}
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EXPORT_SYMBOL(x86_match_cpu);
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static const struct x86_cpu_desc *
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x86_match_cpu_with_stepping(const struct x86_cpu_desc *match)
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{
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struct cpuinfo_x86 *c = &boot_cpu_data;
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const struct x86_cpu_desc *m;
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for (m = match; m->x86_family | m->x86_model; m++) {
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if (c->x86_vendor != m->x86_vendor)
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continue;
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if (c->x86 != m->x86_family)
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continue;
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if (c->x86_model != m->x86_model)
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continue;
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if (c->x86_stepping != m->x86_stepping)
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continue;
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return m;
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}
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return NULL;
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}
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bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table)
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{
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const struct x86_cpu_desc *res = x86_match_cpu_with_stepping(table);
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if (!res || res->x86_microcode_rev > boot_cpu_data.microcode)
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return false;
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return true;
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}
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EXPORT_SYMBOL_GPL(x86_cpu_has_min_microcode_rev);
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