[patch V4 04/30] x86/microcode/intel: Simplify scan_microcode()

From: Thomas Gleixner
Date: Mon Oct 02 2023 - 07:59:54 EST


Make it readable and comprehensible.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/microcode/intel.c | 28 +++++++---------------------
1 file changed, 7 insertions(+), 21 deletions(-)

--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -268,22 +268,16 @@ static void save_microcode_patch(void *d
intel_ucode_patch = (struct microcode_intel *)p;
}

-/*
- * Get microcode matching with BSP's model. Only CPUs with the same model as
- * BSP can stay in the platform.
- */
-static struct microcode_intel *
-scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
+/* Scan CPIO for microcode matching the boot CPUs family, model, stepping */
+static struct microcode_intel *scan_microcode(void *data, size_t size,
+ struct ucode_cpu_info *uci, bool save)
{
struct microcode_header_intel *mc_header;
struct microcode_intel *patch = NULL;
u32 cur_rev = uci->cpu_sig.rev;
unsigned int mc_size;

- while (size) {
- if (size < sizeof(struct microcode_header_intel))
- break;
-
+ for (; size >= sizeof(struct microcode_header_intel); size -= mc_size, data += mc_size) {
mc_header = (struct microcode_header_intel *)data;

mc_size = get_totalsize(mc_header);
@@ -291,27 +285,19 @@ scan_microcode(void *data, size_t size,
intel_microcode_sanity_check(data, false, MC_HEADER_TYPE_MICROCODE) < 0)
break;

- size -= mc_size;
-
- if (!intel_find_matching_signature(data, uci->cpu_sig.sig,
- uci->cpu_sig.pf)) {
- data += mc_size;
+ if (!intel_find_matching_signature(data, uci->cpu_sig.sig, uci->cpu_sig.pf))
continue;
- }

/* BSP scan: Check whether there is newer microcode */
if (!save && cur_rev >= mc_header->rev)
- goto next;
+ continue;

/* Save scan: Check whether there is newer or matching microcode */
if (save && cur_rev != mc_header->rev)
- goto next;
+ continue;

patch = data;
cur_rev = mc_header->rev;
-
-next:
- data += mc_size;
}

if (size)