The following commit has been merged into the x86/cpu branch of tip:
Commit-ID: 1a77c102cee20edb2459334d8eaf3202697ac8f5 Gitweb: https://git.kernel.org/tip/1a77c102cee20edb2459334d8eaf3202697ac8f5 Author: Suchit Karunakaran suchitkarunakaran@gmail.com AuthorDate: Sat, 16 Aug 2025 12:21:26 +05:30 Committer: Dave Hansen dave.hansen@linux.intel.com CommitterDate: Fri, 22 Aug 2025 12:02:59 -07:00
x86/cpu/intel: Fix the constant_tsc model check for Pentium 4
Pentium 4's which are INTEL_P4_PRESCOTT (model 0x03) and later have a constant TSC. This was correctly captured until commit fadb6f569b10 ("x86/cpu/intel: Limit the non-architectural constant_tsc model checks").
In that commit, an error was introduced while selecting the last P4 model (0x06) as the upper bound. Model 0x06 was transposed to INTEL_P4_WILLAMETTE, which is just plain wrong. That was presumably a simple typo, probably just copying and pasting the wrong P4 model.
Fix the constant TSC logic to cover all later P4 models. End at INTEL_P4_CEDARMILL which accurately corresponds to the last P4 model.
Fixes: fadb6f569b10 ("x86/cpu/intel: Limit the non-architectural constant_tsc model checks") Signed-off-by: Suchit Karunakaran suchitkarunakaran@gmail.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Sohil Mehta sohil.mehta@intel.com Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250816065126.5000-1-suchitkarunakaran%40gmail.... --- arch/x86/kernel/cpu/intel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 076eaa4..98ae4c3 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -262,7 +262,7 @@ static void early_init_intel(struct cpuinfo_x86 *c) if (c->x86_power & (1 << 8)) { set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC); - } else if ((c->x86_vfm >= INTEL_P4_PRESCOTT && c->x86_vfm <= INTEL_P4_WILLAMETTE) || + } else if ((c->x86_vfm >= INTEL_P4_PRESCOTT && c->x86_vfm <= INTEL_P4_CEDARMILL) || (c->x86_vfm >= INTEL_CORE_YONAH && c->x86_vfm <= INTEL_IVYBRIDGE)) { set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); }