From: Matthew Whitehead <tedheadster@xxxxxxxxx> [ 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@xxxxxxxxxxxxxx> Signed-off-by: Matthew Whitehead <tedheadster@xxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: David Woodhouse <dwmw@xxxxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20180921212041.13096-3-tedheadster@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 551c6bed7c8ce..1784deefbc8c9 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1037,6 +1037,9 @@ 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); @@ -1053,7 +1056,6 @@ 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); } -- 2.20.1
