diff options
Diffstat (limited to 'arch/x86/kernel/fpu/init.c')
| -rw-r--r-- | arch/x86/kernel/fpu/init.c | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 60dece392b3a..c2f8dde3255c 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -7,6 +7,7 @@ #include <asm/cmdline.h> #include <linux/sched.h> +#include <linux/sched/task.h> #include <linux/init.h> /* @@ -48,13 +49,7 @@ void fpu__init_cpu(void) fpu__init_cpu_xstate(); } -/* - * The earliest FPU detection code. - * - * Set the X86_FEATURE_FPU CPU-capability bit based on - * trying to execute an actual sequence of FPU instructions: - */ -static void fpu__init_system_early_generic(struct cpuinfo_x86 *c) +static bool fpu__probe_without_cpuid(void) { unsigned long cr0; u16 fsw, fcw; @@ -65,18 +60,25 @@ static void fpu__init_system_early_generic(struct cpuinfo_x86 *c) cr0 &= ~(X86_CR0_TS | X86_CR0_EM); write_cr0(cr0); - if (!test_bit(X86_FEATURE_FPU, (unsigned long *)cpu_caps_cleared)) { - asm volatile("fninit ; fnstsw %0 ; fnstcw %1" - : "+m" (fsw), "+m" (fcw)); + asm volatile("fninit ; fnstsw %0 ; fnstcw %1" : "+m" (fsw), "+m" (fcw)); + + pr_info("x86/fpu: Probing for FPU: FSW=0x%04hx FCW=0x%04hx\n", fsw, fcw); - if (fsw == 0 && (fcw & 0x103f) == 0x003f) - set_cpu_cap(c, X86_FEATURE_FPU); + return fsw == 0 && (fcw & 0x103f) == 0x003f; +} + +static void fpu__init_system_early_generic(struct cpuinfo_x86 *c) +{ + if (!boot_cpu_has(X86_FEATURE_CPUID) && + !test_bit(X86_FEATURE_FPU, (unsigned long *)cpu_caps_cleared)) { + if (fpu__probe_without_cpuid()) + setup_force_cpu_cap(X86_FEATURE_FPU); else - clear_cpu_cap(c, X86_FEATURE_FPU); + setup_clear_cpu_cap(X86_FEATURE_FPU); } #ifndef CONFIG_MATH_EMULATION - if (!boot_cpu_has(X86_FEATURE_FPU)) { + if (!test_cpu_cap(&boot_cpu_data, X86_FEATURE_FPU)) { pr_emerg("x86/fpu: Giving up, no FPU found and no math emulation present\n"); for (;;) asm volatile("hlt"); |