From 05fb3c199bb09f5b85de56cc3ede194ac95c5e1f Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 28 Sep 2016 16:06:33 -0700 Subject: [PATCH] x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID Otherwise arch_task_struct_size == 0 and we die. While we're at it, set X86_FEATURE_ALWAYS, too. Reported-by: David Saggiorato Tested-by: David Saggiorato Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: stable@vger.kernel.org Fixes: aaeb5c01c5b ("x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86") Link: http://lkml.kernel.org/r/8de723afbf0811071185039f9088733188b606c9.1475103911.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 809eda03c527..bcc9ccc220c9 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -804,21 +804,20 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) identify_cpu_without_cpuid(c); /* cyrix could have cpuid enabled via c_identify()*/ - if (!have_cpuid_p()) - return; + if (have_cpuid_p()) { + cpu_detect(c); + get_cpu_vendor(c); + get_cpu_cap(c); - cpu_detect(c); - get_cpu_vendor(c); - get_cpu_cap(c); + if (this_cpu->c_early_init) + this_cpu->c_early_init(c); - if (this_cpu->c_early_init) - this_cpu->c_early_init(c); + c->cpu_index = 0; + filter_cpuid_features(c, false); - c->cpu_index = 0; - filter_cpuid_features(c, false); - - if (this_cpu->c_bsp_init) - this_cpu->c_bsp_init(c); + if (this_cpu->c_bsp_init) + this_cpu->c_bsp_init(c); + } setup_force_cpu_cap(X86_FEATURE_ALWAYS); fpu__init_system(c);