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x86/cacheinfo: Consolidate AMD/Hygon leaf 0x8000001d calls

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While gathering CPU cache info, CPUID leaf 0x8000001d is invoked in two
separate if blocks: one for Hygon CPUs and one for AMDs with topology
extensions.  After each invocation, amd_init_l3_cache() is called.

Merge the two if blocks into a single condition, thus removing the
duplicated code.  Future commits will expand these if blocks, so
combining them now is both cleaner and more maintainable.

Note, while at it, remove a useless "better error?" comment that was
within the same function since the 2005 commit e2cac78935 ("[PATCH]
x86_64: When running cpuid4 need to run on the correct CPU").

Note, as previously done at commit aec28d852ed2 ("x86/cpuid: Standardize
on u32 in <asm/cpuid/api.h>"), standardize on using 'u32' and 'u8' types.

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/20250324133324.23458-12-darwi@linutronix.de
This commit is contained in:
Ahmed S. Darwish 2025-03-24 14:33:06 +01:00 committed by Ingo Molnar
parent 1374ff60ed
commit 77676e6802
1 changed files with 14 additions and 14 deletions
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28
arch/x86/kernel/cpu/cacheinfo.c
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@ -593,28 +593,28 @@ static void amd_init_l3_cache(struct _cpuid4_info_regs *id4, int index)
static int
cpuid4_cache_lookup_regs(int index, struct _cpuid4_info_regs *id4)
{
union _cpuid4_leaf_eax eax;
union _cpuid4_leaf_ebx ebx;
union _cpuid4_leaf_ecx ecx;
unsigned edx;
u8 cpu_vendor = boot_cpu_data.x86_vendor;
union _cpuid4_leaf_eax eax;
union _cpuid4_leaf_ebx ebx;
union _cpuid4_leaf_ecx ecx;
u32 edx;
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
if (boot_cpu_has(X86_FEATURE_TOPOEXT))
cpuid_count(0x8000001d, index, &eax.full,
&ebx.full, &ecx.full, &edx);
else
if (cpu_vendor == X86_VENDOR_AMD || cpu_vendor == X86_VENDOR_HYGON) {
if (boot_cpu_has(X86_FEATURE_TOPOEXT) || cpu_vendor == X86_VENDOR_HYGON) {
/* AMD with TOPOEXT, or HYGON */
cpuid_count(0x8000001d, index, &eax.full, &ebx.full, &ecx.full, &edx);
} else {
/* Legacy AMD fallback */
amd_cpuid4(index, &eax, &ebx, &ecx);
amd_init_l3_cache(id4, index);
} else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
cpuid_count(0x8000001d, index, &eax.full,
&ebx.full, &ecx.full, &edx);
}
amd_init_l3_cache(id4, index);
} else {
/* Intel */
cpuid_count(4, index, &eax.full, &ebx.full, &ecx.full, &edx);
}
if (eax.split.type == CTYPE_NULL)
return -EIO; /* better error ? */
return -EIO;
id4->eax = eax;
id4->ebx = ebx;