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| author | Matthew Whitehead <tedheadster@gmail.com> | 2018-09-22 00:20:41 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-20 20:47:14 +0300 |
| commit | e897dd4cfdde740d1ed1d6835ccd7f35836b0b82 (patch) | |
| tree | 0384def28a9a7e6e3056648534d41623342bd944 /arch/x86 | |
| parent | d26ad73be70f5e2545033523d763f48899bf861d (diff) | |
| download | linux-e897dd4cfdde740d1ed1d6835ccd7f35836b0b82.tar.xz | |
x86/CPU: Change query logic so CPUID is enabled before testing
[ Upstream commit 2893cc8ff892fa74972d8dc0e1d0dc65116daaa3 ]
Presently we check first if CPUID is enabled. If it is not already
enabled, then we next call identify_cpu_without_cpuid() and clear
X86_FEATURE_CPUID.
Unfortunately, identify_cpu_without_cpuid() is the function where CPUID
becomes _enabled_ on Cyrix 6x86/6x86L CPUs.
Reverse the calling sequence so that CPUID is first enabled, and then
check a second time to see if the feature has now been activated.
[ bp: Massage commit message and remove trailing whitespace. ]
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180921212041.13096-3-tedheadster@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 1e07814f02bc..a6458ab499c2 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1133,6 +1133,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) memset(&c->x86_capability, 0, sizeof c->x86_capability); c->extended_cpuid_level = 0; + if (!have_cpuid_p()) + identify_cpu_without_cpuid(c); + /* cyrix could have cpuid enabled via c_identify()*/ if (have_cpuid_p()) { cpu_detect(c); @@ -1150,7 +1153,6 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) if (this_cpu->c_bsp_init) this_cpu->c_bsp_init(c); } else { - identify_cpu_without_cpuid(c); setup_clear_cpu_cap(X86_FEATURE_CPUID); } |