x86/microcode: Rework early revisions reporting

The AMD side of the loader issues the microcode revision for each
logical thread on the system, which can become really noisy on huge
machines. And doing that doesn't make a whole lot of sense - the
microcode revision is already in /proc/cpuinfo.

So in case one is interested in the theoretical support of mixed silicon
steppings on AMD, one can check there.

What is also missing on the AMD side - something which people have
requested before - is showing the microcode revision the CPU had
*before* the early update.

So abstract that up in the main code and have the BSP on each vendor
provide those revision numbers.

Then, dump them only once on driver init.

On Intel, do not dump the patch date - it is not needed.

Reported-by: Linus Torvalds <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/CAHk-=wg=%[email protected]

1 files changed, 10 insertions, 4 deletions

diff --git a/arch/x86/kernel/cpu/microcode/internal.h b/arch/x86/kernel/cpu/microcode/internal.h
index f8047b12329a..21776c529fa9 100644
--- a/arch/x86/kernel/cpu/microcode/internal.h
+++ b/arch/x86/kernel/cpu/microcode/internal.h
@@ -37,6 +37,12 @@ struct microcode_ops {
 				use_nmi		: 1;
 };
 
+struct early_load_data {
+	u32 old_rev;
+	u32 new_rev;
+};
+
+extern struct early_load_data early_data;
 extern struct ucode_cpu_info ucode_cpu_info[];
 struct cpio_data find_microcode_in_initrd(const char *path);
 
@@ -92,14 +98,14 @@ extern bool dis_ucode_ldr;
 extern bool force_minrev;
 
 #ifdef CONFIG_CPU_SUP_AMD
-void load_ucode_amd_bsp(unsigned int family);
+void load_ucode_amd_bsp(struct early_load_data *ed, unsigned int family);
 void load_ucode_amd_ap(unsigned int family);
 int save_microcode_in_initrd_amd(unsigned int family);
 void reload_ucode_amd(unsigned int cpu);
 struct microcode_ops *init_amd_microcode(void);
 void exit_amd_microcode(void);
 #else /* CONFIG_CPU_SUP_AMD */
-static inline void load_ucode_amd_bsp(unsigned int family) { }
+static inline void load_ucode_amd_bsp(struct early_load_data *ed, unsigned int family) { }
 static inline void load_ucode_amd_ap(unsigned int family) { }
 static inline int save_microcode_in_initrd_amd(unsigned int family) { return -EINVAL; }
 static inline void reload_ucode_amd(unsigned int cpu) { }
@@ -108,12 +114,12 @@ static inline void exit_amd_microcode(void) { }
 #endif /* !CONFIG_CPU_SUP_AMD */
 
 #ifdef CONFIG_CPU_SUP_INTEL
-void load_ucode_intel_bsp(void);
+void load_ucode_intel_bsp(struct early_load_data *ed);
 void load_ucode_intel_ap(void);
 void reload_ucode_intel(void);
 struct microcode_ops *init_intel_microcode(void);
 #else /* CONFIG_CPU_SUP_INTEL */
-static inline void load_ucode_intel_bsp(void) { }
+static inline void load_ucode_intel_bsp(struct early_load_data *ed) { }
 static inline void load_ucode_intel_ap(void) { }
 static inline void reload_ucode_intel(void) { }
 static inline struct microcode_ops *init_intel_microcode(void) { return NULL; }