linux-kernel - [PATCH v2 04/29] x86/cacheinfo: Use CPUID leaf 0x2 parsing helpers

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Message-ID: <20250317164745.4754-5-darwi@linutronix.de>
Date: Mon, 17 Mar 2025 17:47:20 +0100
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Borislav Petkov <bp@...en8.de>
Cc: Thomas Gleixner <tglx@...utronix.de>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	John Ogness <john.ogness@...utronix.de>,
	x86@...nel.org,
	x86-cpuid@...ts.linux.dev,
	LKML <linux-kernel@...r.kernel.org>,
	"Ahmed S. Darwish" <darwi@...utronix.de>
Subject: [PATCH v2 04/29] x86/cacheinfo: Use CPUID leaf 0x2 parsing helpers

Use the CPUID leaf 0x2 parsing helpers added in previous commits, which
queries the CPUID leaf just once.  This also makes the same leaf 0x2
parsing logic used by both x86/cacheinfo and x86/cpu intel.c

Suggested-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Ahmed S. Darwish <darwi@...utronix.de>
---
 arch/x86/kernel/cpu/cacheinfo.c | 66 +++++++++++++--------------------
 1 file changed, 26 insertions(+), 40 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 584811ffca0c..53f51acefac6 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>
@@ -782,50 +783,35 @@ 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) {
-		/* supports eax=2  call */
-		int j, n;
-		unsigned int regs[4];
-		unsigned char *dp = (unsigned char *)regs;
-
-		/* Number of times to iterate */
-		n = cpuid_eax(2) & 0xFF;
-
-		for (i = 0 ; i < n ; i++) {
-			cpuid(2, &regs[0], &regs[1], &regs[2], &regs[3]);
-
-			/* If bit 31 is set, this is an unknown format */
-			for (j = 0 ; j < 4 ; j++)
-				if (regs[j] & (1 << 31))
-					regs[j] = 0;
-
-			/* Byte 0 is level count, not a descriptor */
-			for (j = 1 ; j < 16 ; j++) {
-				unsigned char des = dp[j];
-				unsigned char k = 0;
-
-				/* look up this descriptor in the table */
-				while (cache_table[k].descriptor != 0) {
-					if (cache_table[k].descriptor == des) {
-						switch (cache_table[k].cache_type) {
-						case LVL_1_INST:
-							l1i += cache_table[k].size;
-							break;
-						case LVL_1_DATA:
-							l1d += cache_table[k].size;
-							break;
-						case LVL_2:
-							l2 += cache_table[k].size;
-							break;
-						case LVL_3:
-							l3 += cache_table[k].size;
-							break;
-						}
-
+		union leaf_0x2_regs regs;
+		u8 *desc;
+
+		cpuid_get_leaf_0x2_regs(&regs);
+		for_each_leaf_0x2_desc(regs, desc) {
+			unsigned char k = 0;
+
+			/* look up this descriptor in the table */
+			while (cache_table[k].descriptor != 0) {
+				if (cache_table[k].descriptor == *desc) {
+					switch (cache_table[k].cache_type) {
+					case LVL_1_INST:
+						l1i += cache_table[k].size;
+						break;
+					case LVL_1_DATA:
+						l1d += cache_table[k].size;
+						break;
+					case LVL_2:
+						l2 += cache_table[k].size;
+						break;
+					case LVL_3:
+						l3 += cache_table[k].size;
 						break;
 					}
 
-					k++;
+					break;
 				}
+
+					k++;
 			}
 		}
 	}
-- 
2.48.1