[PATCH v2] x86/intel: Fix always false range check in x86_vfm model matching

From: Suchit Karunakaran
Date: Tue Jul 29 2025 - 00:26:39 EST


Fix a logic bug in early_init_intel() where a conditional range check:
(c->x86_vfm >= INTEL_P4_PRESCOTT && c->x86_vfm <= INTEL_P4_WILLAMETTE)
was always false due to (PRESCOTT) being numerically greater than the
upper bound (WILLAMETTE). This triggers:-Werror=logical-op:
logical ‘and’ of mutually exclusive tests is always false
The fix corrects the constant ordering to ensure the range is valid:
(c->x86_vfm >= INTEL_P4_PRESCOTT && c->x86_vfm <= INTEL_P4_CEDARMILL)

Fixes: fadb6f569b10 ("x86/cpu/intel: Limit the non-architectural
constant_tsc model checks")

Signed-off-by: Suchit Karunakaran <suchitkarunakaran@xxxxxxxxx>

Changes since v1:
- Fix incorrect logic
---
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 076eaa41b8c8..6f5bd5dbc249 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);
}
--
2.50.1