From: Ahmed S. Darwish <darwi@linutronix.de>
Date: Mon, 24 Mar 2025 13:32:59 +0000 (+0100)
Subject: x86/cacheinfo: Use CPUID leaf 0x2 parsing helpers
X-Git-Tag: v6.16-rc1~195^2~29^2~46
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a078aaa38a23a2595addb14ac286d8b8ae793d39;p=thirdparty%2Flinux.git

x86/cacheinfo: Use CPUID leaf 0x2 parsing helpers

Parent commit introduced CPUID leaf 0x2 parsing helpers at
<asm/cpuid/leaf_0x2_api.h>.  The new API allows sharing leaf 0x2's output
validation and iteration logic across both intel.c and cacheinfo.c.

Convert cacheinfo.c to that new API.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250324133324.23458-5-darwi@linutronix.de
---

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 36782fd017b38..6c610805e3564 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -19,6 +19,7 @@
 #include <asm/amd_nb.h>
 #include <asm/cacheinfo.h>
 #include <asm/cpufeature.h>
+#include <asm/cpuid.h>
 #include <asm/mtrr.h>
 #include <asm/smp.h>
 #include <asm/tlbflush.h>
@@ -783,29 +784,16 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
 
 	/* Don't use CPUID(2) if CPUID(4) is supported. */
 	if (!ci->num_leaves && c->cpuid_level > 1) {
-		u32 regs[4];
-		u8 *desc = (u8 *)regs;
+		union leaf_0x2_regs regs;
+		u8 *desc;
 
-		cpuid(2, &regs[0], &regs[1], &regs[2], &regs[3]);
-
-		/* Intel CPUs must report an iteration count of 1 */
-		if (desc[0] != 0x01)
-			return;
-
-		/* If a register's bit 31 is set, it is an unknown format */
-		for (int i = 0; i < 4; i++) {
-			if (regs[i] & (1 << 31))
-				regs[i] = 0;
-		}
-
-		/* Skip the first byte as it is not a descriptor */
-		for (int i = 1; i < 16; i++) {
-			u8 des = desc[i];
+		cpuid_get_leaf_0x2_regs(&regs);
+		for_each_leaf_0x2_desc(regs, desc) {
 			u8 k = 0;
 
 			/* look up this descriptor in the table */
 			while (cache_table[k].descriptor != 0) {
-				if (cache_table[k].descriptor == des) {
+				if (cache_table[k].descriptor == *desc) {
 					switch (cache_table[k].cache_type) {
 					case LVL_1_INST:
 						l1i += cache_table[k].size;