linux-kernel - [RFC 01/10] x86/microcode/intel: expose collect_cpu_info

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Date:   Tue,  1 Mar 2022 11:54:48 -0800
From:   Jithu Joseph <jithu.joseph@...el.com>
To:     hdegoede@...hat.com, markgross@...nel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        corbet@....net, gregkh@...uxfoundation.org,
        andriy.shevchenko@...ux.intel.com, jithu.joseph@...el.com,
        ashok.raj@...el.com, tony.luck@...el.com, rostedt@...dmis.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, patches@...ts.linux.dev,
        ravi.v.shankar@...el.com
Subject: [RFC 01/10] x86/microcode/intel: expose collect_cpu_info_early() for IFS

IFS uses a image provided by Intel that can be regarded as firmware.
IFS image carries the Processor Signature such as family/model/stepping
similar to what we find in the microcode header.

Expose collect_cpu_info_early() and cpu_signatures_match() for IFS image
sanity check.

No functional change.

Originally-by: Kyung Min Park <kyung.min.park@...el.com>
Signed-off-by: Jithu Joseph <jithu.joseph@...el.com>
Reviewed-by: Ashok Raj <ashok.raj@...el.com>
Reviewed-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/include/asm/microcode_intel.h | 6 ++++++
 arch/x86/kernel/cpu/microcode/intel.c  | 8 +++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/microcode_intel.h b/arch/x86/include/asm/microcode_intel.h
index d85a07d7154f..ec19eeac535b 100644
--- a/arch/x86/include/asm/microcode_intel.h
+++ b/arch/x86/include/asm/microcode_intel.h
@@ -74,12 +74,18 @@ extern void load_ucode_intel_ap(void);
 extern void show_ucode_info_early(void);
 extern int __init save_microcode_in_initrd_intel(void);
 void reload_ucode_intel(void);
+int collect_cpu_info_early(struct ucode_cpu_info *uci);
+bool cpu_signatures_match(unsigned int s1, unsigned int p1,
+			  unsigned int s2, unsigned int p2);
 #else
 static inline __init void load_ucode_intel_bsp(void) {}
 static inline void load_ucode_intel_ap(void) {}
 static inline void show_ucode_info_early(void) {}
 static inline int __init save_microcode_in_initrd_intel(void) { return -EINVAL; }
 static inline void reload_ucode_intel(void) {}
+static inline void collect_cpu_info_early(struct ucode_cpu_info *uci) {}
+static inline void cpu_signatures_match(unsigned int s1, unsigned int p1,
+					unsigned int s2, unsigned int p2) {}
 #endif
 
 #endif /* _ASM_X86_MICROCODE_INTEL_H */
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index d28a9f8f3fec..360ec06eec1e 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -45,8 +45,8 @@ static struct microcode_intel *intel_ucode_patch;
 /* last level cache size per core */
 static int llc_size_per_core;
 
-static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
-					unsigned int s2, unsigned int p2)
+bool cpu_signatures_match(unsigned int s1, unsigned int p1,
+			  unsigned int s2, unsigned int p2)
 {
 	if (s1 != s2)
 		return false;
@@ -58,6 +58,7 @@ static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
 	/* ... or they intersect. */
 	return p1 & p2;
 }
+EXPORT_SYMBOL_GPL(cpu_signatures_match);
 
 /*
  * Returns 1 if update has been found, 0 otherwise.
@@ -342,7 +343,7 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
 	return patch;
 }
 
-static int collect_cpu_info_early(struct ucode_cpu_info *uci)
+int collect_cpu_info_early(struct ucode_cpu_info *uci)
 {
 	unsigned int val[2];
 	unsigned int family, model;
@@ -372,6 +373,7 @@ static int collect_cpu_info_early(struct ucode_cpu_info *uci)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(collect_cpu_info_early);
 
 static void show_saved_mc(void)
 {
-- 
2.17.1