Commit f8b2507c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 2d5438f4 edc0a2b5

arch/x86/kernel/cpu/topology.c

+3 −2
Original line number Diff line number Diff line
@@ -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);