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

Pull x86 FPU updates from Thomas Gleixner:
 "A small set of updates for the FPU code:

   - Make the no387/nofxsr command line options useful by restricting
     them to 32bit and actually clearing all dependencies to prevent
     random crashes and malfunction.

   - Simplify and cleanup the kernel_fpu_*() helpers"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu: Inline fpu__xstate_clear_all_cpu_caps()
  x86/fpu: Make 'no387' and 'nofxsr' command line options useful
  x86/fpu: Remove the fpu__save() export
  x86/fpu: Simplify kernel_fpu_begin()
  x86/fpu: Simplify kernel_fpu_end()

arch/x86/include/asm/fpu/xstate.h

@@ -47,7 +47,6 @@ extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
 extern void __init update_regset_xstate_info(unsigned int size,
 					     u64 xstate_mask);
 
-void fpu__xstate_clear_all_cpu_caps(void);
 void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
 const void *get_xsave_field_ptr(int xfeature_nr);
 int using_compacted_format(void);

arch/x86/kernel/cpu/cpuid-deps.c

@@ -20,6 +20,7 @@ struct cpuid_dep {
  * but it's difficult to tell that to the init reference checker.
  */
 static const struct cpuid_dep cpuid_deps[] = {
+	{ X86_FEATURE_FXSR,		X86_FEATURE_FPU	      },
 	{ X86_FEATURE_XSAVEOPT,		X86_FEATURE_XSAVE     },
 	{ X86_FEATURE_XSAVEC,		X86_FEATURE_XSAVE     },
 	{ X86_FEATURE_XSAVES,		X86_FEATURE_XSAVE     },
@@ -27,7 +28,11 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_PKU,		X86_FEATURE_XSAVE     },
 	{ X86_FEATURE_MPX,		X86_FEATURE_XSAVE     },
 	{ X86_FEATURE_XGETBV1,		X86_FEATURE_XSAVE     },
+	{ X86_FEATURE_CMOV,		X86_FEATURE_FXSR      },
+	{ X86_FEATURE_MMX,		X86_FEATURE_FXSR      },
+	{ X86_FEATURE_MMXEXT,		X86_FEATURE_MMX       },
 	{ X86_FEATURE_FXSR_OPT,		X86_FEATURE_FXSR      },
+	{ X86_FEATURE_XSAVE,		X86_FEATURE_FXSR      },
 	{ X86_FEATURE_XMM,		X86_FEATURE_FXSR      },
 	{ X86_FEATURE_XMM2,		X86_FEATURE_XMM       },
 	{ X86_FEATURE_XMM3,		X86_FEATURE_XMM2      },

arch/x86/kernel/fpu/core.c

@@ -43,18 +43,6 @@ static DEFINE_PER_CPU(bool, in_kernel_fpu);
  */
 DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);
 
-static void kernel_fpu_disable(void)
-{
-	WARN_ON_FPU(this_cpu_read(in_kernel_fpu));
-	this_cpu_write(in_kernel_fpu, true);
-}
-
-static void kernel_fpu_enable(void)
-{
-	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
-	this_cpu_write(in_kernel_fpu, false);
-}
-
 static bool kernel_fpu_disabled(void)
 {
 	return this_cpu_read(in_kernel_fpu);
@@ -94,42 +82,33 @@ bool irq_fpu_usable(void)
 }
 EXPORT_SYMBOL(irq_fpu_usable);
 
-static void __kernel_fpu_begin(void)
+void kernel_fpu_begin(void)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	preempt_disable();
 
 	WARN_ON_FPU(!irq_fpu_usable());
+	WARN_ON_FPU(this_cpu_read(in_kernel_fpu));
 
-	kernel_fpu_disable();
+	this_cpu_write(in_kernel_fpu, true);
 
-	if (!(current->flags & PF_KTHREAD)) {
-		if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
-			set_thread_flag(TIF_NEED_FPU_LOAD);
-			/*
-			 * Ignore return value -- we don't care if reg state
-			 * is clobbered.
-			 */
-			copy_fpregs_to_fpstate(fpu);
-		}
+	if (!(current->flags & PF_KTHREAD) &&
+	    !test_thread_flag(TIF_NEED_FPU_LOAD)) {
+		set_thread_flag(TIF_NEED_FPU_LOAD);
+		/*
+		 * Ignore return value -- we don't care if reg state
+		 * is clobbered.
+		 */
+		copy_fpregs_to_fpstate(&current->thread.fpu);
 	}
 	__cpu_invalidate_fpregs_state();
 }
-
-static void __kernel_fpu_end(void)
-{
-	kernel_fpu_enable();
-}
-
-void kernel_fpu_begin(void)
-{
-	preempt_disable();
-	__kernel_fpu_begin();
-}
 EXPORT_SYMBOL_GPL(kernel_fpu_begin);
 
 void kernel_fpu_end(void)
 {
-	__kernel_fpu_end();
+	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
+
+	this_cpu_write(in_kernel_fpu, false);
 	preempt_enable();
 }
 EXPORT_SYMBOL_GPL(kernel_fpu_end);
@@ -155,7 +134,6 @@ void fpu__save(struct fpu *fpu)
 	trace_x86_fpu_after_save(fpu);
 	fpregs_unlock();
 }
-EXPORT_SYMBOL_GPL(fpu__save);
 
 /*
  * Legacy x87 fpstate state init:

arch/x86/kernel/fpu/init.c

@@ -204,12 +204,6 @@ static void __init fpu__init_system_xstate_size_legacy(void)
 	 */
 
 	if (!boot_cpu_has(X86_FEATURE_FPU)) {
-		/*
-		 * Disable xsave as we do not support it if i387
-		 * emulation is enabled.
-		 */
-		setup_clear_cpu_cap(X86_FEATURE_XSAVE);
-		setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
 		fpu_kernel_xstate_size = sizeof(struct swregs_state);
 	} else {
 		if (boot_cpu_has(X86_FEATURE_FXSR))
@@ -252,17 +246,20 @@ static void __init fpu__init_parse_early_param(void)
 	char *argptr = arg;
 	int bit;
 
+#ifdef CONFIG_X86_32
 	if (cmdline_find_option_bool(boot_command_line, "no387"))
+#ifdef CONFIG_MATH_EMULATION
 		setup_clear_cpu_cap(X86_FEATURE_FPU);
+#else
+		pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
+#endif
 
-	if (cmdline_find_option_bool(boot_command_line, "nofxsr")) {
+	if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
 		setup_clear_cpu_cap(X86_FEATURE_FXSR);
-		setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);
-		setup_clear_cpu_cap(X86_FEATURE_XMM);
-	}
+#endif
 
 	if (cmdline_find_option_bool(boot_command_line, "noxsave"))
-		fpu__xstate_clear_all_cpu_caps();
+		setup_clear_cpu_cap(X86_FEATURE_XSAVE);
 
 	if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))
 		setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);

arch/x86/kernel/fpu/xstate.c

@@ -67,15 +67,6 @@ static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
  */
 unsigned int fpu_user_xstate_size;
 
-/*
- * Clear all of the X86_FEATURE_* bits that are unavailable
- * when the CPU has no XSAVE support.
- */
-void fpu__xstate_clear_all_cpu_caps(void)
-{
-	setup_clear_cpu_cap(X86_FEATURE_XSAVE);
-}
-
 /*
  * Return whether the system supports a given xfeature.
  *
@@ -709,7 +700,7 @@ static void fpu__init_disable_system_xstate(void)
 {
 	xfeatures_mask = 0;
 	cr4_clear_bits(X86_CR4_OSXSAVE);
-	fpu__xstate_clear_all_cpu_caps();
+	setup_clear_cpu_cap(X86_FEATURE_XSAVE);
 }
 
 /*