Calling get_cpu_cap() will reset a bunch of CPU features. This will
cause the system to lose track of force-set and force-cleared
featueres in the words that are reset until the end of CPU
initialization. This can cause X86_FEATURE_FPU, for example, to
change back and forth during boot and potentially confuse CPU setup.
To minimize the chance of confusion, re-apply forced caps every time
get_cpu_cap() is called.
Signed-off-by: Andy Lutomirski <l...@kernel.org>
---
arch/x86/kernel/cpu/common.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 347ae0a19380..24e1e4004d42 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -758,6 +758,13 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
init_scattered_cpuid_features(c);
+
+ /*
+ * Clear/Set all flags overridden by options, after probe.
+ * This needs to happen each time we re-probe, which may happen
+ * several times during CPU initialization.
+ */
+ apply_forced_caps(c);
}
static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
--
2.9.3
