1 files changed, 48 insertions, 11 deletions

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index cb339097b9ea..b627746f6b1a 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -131,7 +131,7 @@ static void __cpuinit init_thread_xstate(void)
          * xsave_init().
          */
 
-        if (!HAVE_HWFP) {
+        if (!cpu_has_fpu) {
                 /*
                  * Disable xsave as we do not support it if i387
                  * emulation is enabled.
@@ -158,6 +158,14 @@ void __cpuinit fpu_init(void)
         unsigned long cr0;
         unsigned long cr4_mask = 0;
 
+#ifndef CONFIG_MATH_EMULATION
+        if (!cpu_has_fpu) {
+                pr_emerg("No FPU found and no math emulation present\n");
+                pr_emerg("Giving up\n");
+                for (;;)
+                        asm volatile("hlt");
+        }
+#endif
         if (cpu_has_fxsr)
                 cr4_mask |= X86_CR4_OSFXSR;
         if (cpu_has_xmm)
@@ -167,7 +175,7 @@ void __cpuinit fpu_init(void)
 
         cr0 = read_cr0();
         cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
-        if (!HAVE_HWFP)
+        if (!cpu_has_fpu)
                 cr0 |= X86_CR0_EM;
         write_cr0(cr0);
 
@@ -185,7 +193,7 @@ void __cpuinit fpu_init(void)
 
 void fpu_finit(struct fpu *fpu)
 {
-        if (!HAVE_HWFP) {
+        if (!cpu_has_fpu) {
                 finit_soft_fpu(&fpu->state->soft);
                 return;
         }
@@ -214,7 +222,7 @@ int init_fpu(struct task_struct *tsk)
         int ret;
 
         if (tsk_used_math(tsk)) {
-                if (HAVE_HWFP && tsk == current)
+                if (cpu_has_fpu && tsk == current)
                         unlazy_fpu(tsk);
                 tsk->thread.fpu.last_cpu = ~0;
                 return 0;
@@ -511,14 +519,13 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset,
         if (ret)
                 return ret;
 
-        if (!HAVE_HWFP)
+        if (!static_cpu_has(X86_FEATURE_FPU))
                 return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
 
-        if (!cpu_has_fxsr) {
+        if (!cpu_has_fxsr)
                 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                            &target->thread.fpu.state->fsave, 0,
                                            -1);
-        }
 
         sanitize_i387_state(target);
 
@@ -545,13 +552,13 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
 
         sanitize_i387_state(target);
 
-        if (!HAVE_HWFP)
+        if (!static_cpu_has(X86_FEATURE_FPU))
                 return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
 
-        if (!cpu_has_fxsr) {
+        if (!cpu_has_fxsr)
                 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
-                                          &target->thread.fpu.state->fsave, 0, -1);
-        }
+                                          &target->thread.fpu.state->fsave, 0,
+                                          -1);
 
         if (pos > 0 || count < sizeof(env))
                 convert_from_fxsr(&env, target);
@@ -592,3 +599,33 @@ int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu)
 EXPORT_SYMBOL(dump_fpu);
 
 #endif  /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
+
+static int __init no_387(char *s)
+{
+        setup_clear_cpu_cap(X86_FEATURE_FPU);
+        return 1;
+}
+
+__setup("no387", no_387);
+
+void __cpuinit fpu_detect(struct cpuinfo_x86 *c)
+{
+        unsigned long cr0;
+        u16 fsw, fcw;
+
+        fsw = fcw = 0xffff;
+
+        cr0 = read_cr0();
+        cr0 &= ~(X86_CR0_TS | X86_CR0_EM);
+        write_cr0(cr0);
+
+        asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
+                     : "+m" (fsw), "+m" (fcw));
+
+        if (fsw == 0 && (fcw & 0x103f) == 0x003f)
+                set_cpu_cap(c, X86_FEATURE_FPU);
+        else
+                clear_cpu_cap(c, X86_FEATURE_FPU);
+
+        /* The final cr0 value is set in fpu_init() */
+}