Messages in this thread Patch in this message | | | From | Matthew Whitehead <> | Subject | [PATCH v2 2/2] x86/cpu: Change query logic so cpuid is enabled before testing | Date | Fri, 21 Sep 2018 17:20:41 -0400 |
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Presently we check for cpuid to be enabled first. 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. So we must 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.
Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Matthew Whitehead <tedheadster@gmail.com> --- arch/x86/kernel/cpu/common.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index eb4cb3efd20e..60c7c5ce7e55 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1040,6 +1040,9 @@ 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); @@ -1057,7 +1060,6 @@ 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); } -- 2.16.4
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