linux-kernel - [PATCH v4 04/29] x86/cacheinfo: Use leaf 0x2 parsing helpers

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Message-ID: <20250324133324.23458-5-darwi@linutronix.de>
Date: Mon, 24 Mar 2025 14:32:59 +0100
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>
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 v4 04/29] x86/cacheinfo: Use 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@...utronix.de>
---
 arch/x86/kernel/cpu/cacheinfo.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 36782fd017b3..6c610805e356 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;
-- 
2.48.1