Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 FPU changes from Ingo Molnar:
 "There are two bigger changes in this tree:

   - Add an [early-use-]safe static_cpu_has() variant and other
     robustness improvements, including the new X86_DEBUG_STATIC_CPU_HAS
     configurable debugging facility, motivated by recent obscure FPU
     code bugs, by Borislav Petkov

   - Reimplement FPU detection code in C and drop the old asm code, by
     Peter Anvin."

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, fpu: Use static_cpu_has_safe before alternatives
  x86: Add a static_cpu_has_safe variant
  x86: Sanity-check static_cpu_has usage
  x86, cpu: Add a synthetic, always true, cpu feature
  x86: Get rid of ->hard_math and all the FPU asm fu

4 files changed, 22 insertions, 24 deletions

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 4112be9a465..03445346ee0 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -17,15 +17,6 @@
 #include <asm/paravirt.h>
 #include <asm/alternative.h>
 
-static int __init no_387(char *s)
-{
-	boot_cpu_data.hard_math = 0;
-	write_cr0(X86_CR0_TS | X86_CR0_EM | X86_CR0_MP | read_cr0());
-	return 1;
-}
-
-__setup("no387", no_387);
-
 static double __initdata x = 4195835.0;
 static double __initdata y = 3145727.0;
 
@@ -44,15 +35,6 @@ static void __init check_fpu(void)
 {
 	s32 fdiv_bug;
 
-	if (!boot_cpu_data.hard_math) {
-#ifndef CONFIG_MATH_EMULATION
-		pr_emerg("No coprocessor found and no math emulation present\n");
-		pr_emerg("Giving up\n");
-		for (;;) ;
-#endif
-		return;
-	}
-
 	kernel_fpu_begin();
 
 	/*
@@ -107,5 +89,6 @@ void __init check_bugs(void)
 	 * kernel_fpu_begin/end() in check_fpu() relies on the patched
 	 * alternative instructions.
 	 */
-	check_fpu();
+	if (cpu_has_fpu)
+		check_fpu();
 }
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 22018f70a67..a4a07c0acb1 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -711,10 +711,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 		return;
 
 	cpu_detect(c);
-
 	get_cpu_vendor(c);
-
 	get_cpu_cap(c);
+	fpu_detect(c);
 
 	if (this_cpu->c_early_init)
 		this_cpu->c_early_init(c);
@@ -724,6 +723,8 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 
 	if (this_cpu->c_bsp_init)
 		this_cpu->c_bsp_init(c);
+
+	setup_force_cpu_cap(X86_FEATURE_ALWAYS);
 }
 
 void __init early_cpu_init(void)
@@ -1363,3 +1364,17 @@ void __cpuinit cpu_init(void)
 	fpu_init();
 }
 #endif
+
+#ifdef CONFIG_X86_DEBUG_STATIC_CPU_HAS
+void warn_pre_alternatives(void)
+{
+	WARN(1, "You're using static_cpu_has before alternatives have run!\n");
+}
+EXPORT_SYMBOL_GPL(warn_pre_alternatives);
+#endif
+
+inline bool __static_cpu_has_safe(u16 bit)
+{
+	return boot_cpu_has(bit);
+}
+EXPORT_SYMBOL_GPL(__static_cpu_has_safe);
diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c
index d048d5ca43c..7582f475b16 100644
--- a/arch/x86/kernel/cpu/cyrix.c
+++ b/arch/x86/kernel/cpu/cyrix.c
@@ -333,7 +333,7 @@ static void __cpuinit init_cyrix(struct cpuinfo_x86 *c)
 		switch (dir0_lsn) {
 		case 0xd:  /* either a 486SLC or DLC w/o DEVID */
 			dir0_msn = 0;
-			p = Cx486_name[(c->hard_math) ? 1 : 0];
+			p = Cx486_name[(cpu_has_fpu ? 1 : 0)];
 			break;
 
 		case 0xe:  /* a 486S A step */
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 37a198bd48c..aee6317b902 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -37,8 +37,8 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
 		   static_cpu_has_bug(X86_BUG_FDIV) ? "yes" : "no",
 		   static_cpu_has_bug(X86_BUG_F00F) ? "yes" : "no",
 		   static_cpu_has_bug(X86_BUG_COMA) ? "yes" : "no",
-		   c->hard_math ? "yes" : "no",
-		   c->hard_math ? "yes" : "no",
+		   static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no",
+		   static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no",
 		   c->cpuid_level,
 		   c->wp_works_ok ? "yes" : "no");
 }