[coreboot-gerrit] Change in coreboot[master]: cpu/intel/microcode: Add caching layer in intel_microcode_find

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change. ( https://review.coreboot.org/c/coreboot/+/49896 )

Change subject: cpu/intel/microcode: Add caching layer in intel_microcode_find
......................................................................

cpu/intel/microcode: Add caching layer in intel_microcode_find

Cache the found microcode for faster subsequent accesses.

Change-Id: Ic40d57964600f8f20ddb26c7d1691b043fd89f29
Signed-off-by: Patrick Rudolph 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49896
Reviewed-by: Angel Pons 
Reviewed-by: Arthur Heymans 
Tested-by: build bot (Jenkins) 
---
M src/cpu/intel/microcode/microcode.c
M src/include/cpu/intel/microcode.h
2 files changed, 9 insertions(+), 2 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Arthur Heymans: Looks good to me, approved
  Angel Pons: Looks good to me, approved

diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c
index 0f362d4..9d6d28b 100644
--- a/src/cpu/intel/microcode/microcode.c
+++ b/src/cpu/intel/microcode/microcode.c
@@ -119,13 +119,16 @@

const void *intel_microcode_find(void)
 {
-	const struct microcode *ucode_updates;
+	static const struct microcode *ucode_updates;
    size_t microcode_len;
    u32 eax;
    u32 pf, rev, sig, update_size;
    unsigned int x86_model, x86_family;
    msr_t msr;

+	if (ucode_updates)
+		return ucode_updates;
+
    ucode_updates = cbfs_map(MICROCODE_CBFS_FILE, &microcode_len);
    if (ucode_updates == NULL)
    	return NULL;
@@ -173,6 +176,8 @@
    	microcode_len -= update_size;
    }

+	ucode_updates = NULL;
+
    return NULL;
 }

diff --git a/src/include/cpu/intel/microcode.h b/src/include/cpu/intel/microcode.h
index f1a8601..7fd6eac 100644
--- a/src/include/cpu/intel/microcode.h
+++ b/src/include/cpu/intel/microcode.h
@@ -6,8 +6,10 @@

void intel_update_microcode_from_cbfs(void);
 /* Find a microcode that matches the revision and platform family returning
- * NULL if none found. */
+ * NULL if none found. The found microcode is cached for faster access on
+ * subsequent calls of this function. */
 const void *intel_microcode_find(void);
+
 /* It is up to the caller to determine if parallel loading is possible as
  * well as ensuring the microcode matches the family and revision (i.e. with
  * intel_microcode_find()). */