x86, fpu: Merge fpu_init()

Make fpu_init() handle 32-bit setup.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1283563039-3466-3-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/cpu/common.c

@@ -1264,13 +1264,6 @@ void __cpuinit cpu_init(void)
 	clear_all_debug_regs();
 	dbg_restore_debug_regs();
 
-	/*
-	 * Force FPU initialization:
-	 */
-	current_thread_info()->status = 0;
-	clear_used_math();
-	mxcsr_feature_mask_init();
-
 	fpu_init();
 	xsave_init();
 }

arch/x86/kernel/i387.c

@@ -85,7 +85,6 @@ static void __cpuinit init_thread_xstate(void)
 #endif
 }
 
-#ifdef CONFIG_X86_64
 /*
  * Called at bootup to set up the initial FPU state that is later cloned
  * into all processes.
@@ -93,12 +92,21 @@ static void __cpuinit init_thread_xstate(void)
 
 void __cpuinit fpu_init(void)
 {
-	unsigned long oldcr0 = read_cr0();
-
-	set_in_cr4(X86_CR4_OSFXSR);
-	set_in_cr4(X86_CR4_OSXMMEXCPT);
+	unsigned long cr0;
+	unsigned long cr4_mask = 0;
 
-	write_cr0(oldcr0 & ~(X86_CR0_TS|X86_CR0_EM)); /* clear TS and EM */
+	if (cpu_has_fxsr)
+		cr4_mask |= X86_CR4_OSFXSR;
+	if (cpu_has_xmm)
+		cr4_mask |= X86_CR4_OSXMMEXCPT;
+	if (cr4_mask)
+		set_in_cr4(cr4_mask);
+
+	cr0 = read_cr0();
+	cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
+	if (!HAVE_HWFP)
+		cr0 |= X86_CR0_EM;
+	write_cr0(cr0);
 
 	if (!smp_processor_id())
 		init_thread_xstate();
@@ -109,16 +117,6 @@ void __cpuinit fpu_init(void)
 	clear_used_math();
 }
 
-#else	/* CONFIG_X86_64 */
-
-void __cpuinit fpu_init(void)
-{
-	if (!smp_processor_id())
-		init_thread_xstate();
-}
-
-#endif	/* CONFIG_X86_32 */
-
 void fpu_finit(struct fpu *fpu)
 {
 #ifdef CONFIG_X86_32

arch/x86/kernel/traps.c

@@ -881,18 +881,6 @@ void __init trap_init(void)
 #endif
 
 #ifdef CONFIG_X86_32
-	if (cpu_has_fxsr) {
-		printk(KERN_INFO "Enabling fast FPU save and restore... ");
-		set_in_cr4(X86_CR4_OSFXSR);
-		printk("done.\n");
-	}
-	if (cpu_has_xmm) {
-		printk(KERN_INFO
-			"Enabling unmasked SIMD FPU exception support... ");
-		set_in_cr4(X86_CR4_OSXMMEXCPT);
-		printk("done.\n");
-	}
-
 	set_system_trap_gate(SYSCALL_VECTOR, &system_call);
 	set_bit(SYSCALL_VECTOR, used_vectors);
 #endif