diff options
| author | Andy Lutomirski <[email protected]> | 2017-01-18 11:15:39 -0800 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2017-01-25 10:12:41 +0100 |
| commit | 60d3450167433f2d099ce2869dc52dd9e7dc9b29 (patch) | |
| tree | 785d108a16027aaa1f666acfeefccb4d3bc3b1c5 | |
| parent | 8bf1ebca215c262e48c15a4a15f175991776f57f (diff) | |
x86/cpu: Re-apply forced caps every time CPU caps are re-read
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
features 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 <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Matthew Whitehead <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: One Thousand Gnomes <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Yu-cheng Yu <[email protected]>
Link: http://lkml.kernel.org/r/c817eb373d2c67c2c81413a70fc9b845fa34a37e.1484705016.git.luto@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 2ea16e05de43..d09b5eefaddf 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) |