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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-05-28 07:42:05 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-05-28 07:42:05 -0400 |
| commit | f8b2507c263d6c1478d179c7c260064a61f14542 (patch) | |
| tree | 8db6dcfff2a4ade5a0d66a271d07bd34a0c5b6d1 | |
| parent | 2d5438f4c6fdaa34c5d7de89a5331b8dbcd920af (diff) | |
| parent | edc0a2b5957652f4685ef3516f519f84807087db (diff) | |
| download | lwn-f8b2507c263d6c1478d179c7c260064a61f14542.tar.gz lwn-f8b2507c263d6c1478d179c7c260064a61f14542.zip | |
Merge tag 'x86-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu fix from Thomas Gleixner:
"A single fix for x86:
- Prevent a bogus setting for the number of HT siblings, which is
caused by the CPUID evaluation trainwreck of X86. That recomputes
the value for each CPU, so the last CPU "wins". That can cause
completely bogus sibling values"
* tag 'x86-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/topology: Fix erroneous smp_num_siblings on Intel Hybrid platforms
| -rw-r--r-- | arch/x86/kernel/cpu/topology.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c index 5e868b62a7c4..0270925fe013 100644 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -79,7 +79,7 @@ int detect_extended_topology_early(struct cpuinfo_x86 *c) * initial apic id, which also represents 32-bit extended x2apic id. */ c->initial_apicid = edx; - smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); + smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx)); #endif return 0; } @@ -109,7 +109,8 @@ int detect_extended_topology(struct cpuinfo_x86 *c) */ cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx); c->initial_apicid = edx; - core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); + core_level_siblings = LEVEL_MAX_SIBLINGS(ebx); + smp_num_siblings = max_t(int, smp_num_siblings, LEVEL_MAX_SIBLINGS(ebx)); core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); die_level_siblings = LEVEL_MAX_SIBLINGS(ebx); pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); |