linux-kernel - [PATCH v1 06/12] tools/x86/kcpuid: Extend CPUID index mask macro

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Message-ID: <20250306205000.227399-7-darwi@linutronix.de>
Date: Thu,  6 Mar 2025 21:49:54 +0100
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: Borislav Petkov <bp@...en8.de>,
	Ingo Molnar <mingo@...hat.com>,
	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>,
	x86@...nel.org,
	John Ogness <john.ogness@...utronix.de>,
	x86-cpuid@...ts.linux.dev,
	LKML <linux-kernel@...r.kernel.org>,
	"Ahmed S. Darwish" <darwi@...utronix.de>
Subject: [PATCH v1 06/12] tools/x86/kcpuid: Extend CPUID index mask macro

Extend the CPUID index mask macro from 0x80000000 to 0xffff0000.  This
accommodates the Centaur-specific indices (0x80860000+) which will be
later added.

Note that this also automatically sets CPUID_FUNCTION_MASK to 0x0000ffff,
which is the actual correct value.  Use it instead of the 0xffff literal
where appropriate.

Signed-off-by: Ahmed S. Darwish <darwi@...utronix.de>
---
 tools/arch/x86/kcpuid/kcpuid.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/arch/x86/kcpuid/kcpuid.c b/tools/arch/x86/kcpuid/kcpuid.c
index 6f6a394486af..6a4c845bc1de 100644
--- a/tools/arch/x86/kcpuid/kcpuid.c
+++ b/tools/arch/x86/kcpuid/kcpuid.c
@@ -70,7 +70,7 @@ enum range_index {
 	RANGE_EXT = 0x80000000,		/* Extended */
 };
 
-#define CPUID_INDEX_MASK		0x80000000
+#define CPUID_INDEX_MASK		0xffff0000
 #define CPUID_FUNCTION_MASK		(~CPUID_INDEX_MASK)
 
 struct cpuid_range {
@@ -174,7 +174,7 @@ static bool cpuid_store(struct cpuid_range *range, u32 f, int subleaf,
 	 * Cut off vendor-prefix from CPUID function as we're using it as an
 	 * index into ->funcs.
 	 */
-	func = &range->funcs[f & 0xffff];
+	func = &range->funcs[f & CPUID_FUNCTION_MASK];
 
 	if (!func->leafs) {
 		func->leafs = malloc(sizeof(struct subleaf));
@@ -236,7 +236,7 @@ void setup_cpuid_range(struct cpuid_range *range)
 
 	cpuid(&eax, &ebx, &ecx, &edx);
 	max_func = eax;
-	idx_func = (max_func & 0xffff) + 1;
+	idx_func = (max_func & CPUID_FUNCTION_MASK) + 1;
 
 	range->funcs = malloc(sizeof(struct cpuid_func) * idx_func);
 	if (!range->funcs)
@@ -546,7 +546,7 @@ static inline struct cpuid_func *index_to_func(u32 index)
 	if (!range)
 		return NULL;
 
-	func_idx = index & 0xffff;
+	func_idx = index & CPUID_FUNCTION_MASK;
 	if ((func_idx + 1) > (u32)range->nr) {
 		warnx("Invalid input index (0x%x)", index);
 		return NULL;
-- 
2.48.1