From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
For bug workarounds or checks it is useful to check for specific
microcode versions. Add a new table format to check for steppings
with min/max microcode revisions.
This does not change the existing x86_cpu_id because it's an ABI
shared with modutils, and also has quite difference requirements,
as in no wildcards, but everything has to be matched exactly.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/cpu_device_id.h | 22 ++++++++++++++
arch/x86/kernel/cpu/match.c | 43 ++++++++++++++++++++++++++++
2 files changed, 65 insertions(+)
diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
index baeba0567126..bf2222d5438c 100644
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -11,4 +11,26 @@
extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
+/*
+ * Match specific microcodes or steppings.
+ *
+ * vendor/family/model/stepping must be all set.
+ * min_ucode/max_ucode/driver_data are optional and can be 0.
+ */
+
+struct x86_ucode_id {
+ __u16 vendor;
+ __u16 family;
+ __u16 model;
+ __u16 stepping;
+ __u32 min_ucode;
+ __u32 max_ucode;
+ kernel_ulong_t driver_data;
+};
+
+extern const struct x86_ucode_id *
+x86_match_ucode_cpu(int cpu, const struct x86_ucode_id *match);
+extern const struct x86_ucode_id *
+x86_match_ucode_all(const struct x86_ucode_id *match);
+
#endif
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index 3fed38812eea..f29a21b2809c 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -48,3 +48,46 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
return NULL;
}
EXPORT_SYMBOL(x86_match_cpu);
+
+const struct x86_ucode_id *x86_match_ucode_cpu(int cpu,
+ const struct x86_ucode_id *match)
+{
+ const struct x86_ucode_id *m;
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+ for (m = match; m->vendor | m->family | m->model; m++) {
+ if (c->x86_vendor != m->vendor)
+ continue;
+ if (c->x86 != m->family)
+ continue;
+ if (c->x86_model != m->model)
+ continue;
+ if (c->x86_stepping != m->stepping)
+ continue;
+ if (m->min_ucode && c->microcode < m->min_ucode)
+ continue;
+ if (m->max_ucode && c->microcode > m->max_ucode)
+ continue;
+ return m;
+ }
+ return NULL;
+}
+
+/* Check all CPUs */
+const struct x86_ucode_id *x86_match_ucode_all(const struct x86_ucode_id *match)
+{
+ int cpu;
+ const struct x86_ucode_id *all_m = NULL;
+ bool first = true;
+
+ for_each_online_cpu(cpu) {
+ const struct x86_ucode_id *m = x86_match_ucode_cpu(cpu, match);
+
+ if (first)
+ all_m = m;
+ else if (m != all_m)
+ return NULL;
+ first = false;
+ }
+ return all_m;
+}
--
2.17.1
