x86/microcode/intel: Simplify scan_microcode()

Make it readable and comprehensible.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115902.271940980@linutronix.de

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 03a55bf..26f759b 100644 (file)
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -266,22 +266,16 @@ static void save_microcode_patch(void *data, unsigned int size)
        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 CPU's 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);
@@ -289,27 +283,19 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
                    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)