linux-kernel - [PATCH 05/10] x86/cpufeature: Remove cpu_has

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Date:	Mon,  4 Apr 2016 22:24:58 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	X86 ML <x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 05/10] x86/cpufeature: Remove cpu_has_fpu

From: Borislav Petkov <bp@...e.de>

Use static_cpu_has() in the timing-sensitive paths in fpstate_init() and
fpu__copy().

While at it, simplify the use in init_cyrix() and get rid of the ternary
operator.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/include/asm/cpufeature.h | 1 -
 arch/x86/kernel/cpu/cyrix.c       | 2 +-
 arch/x86/kernel/fpu/bugs.c        | 2 +-
 arch/x86/kernel/fpu/core.c        | 4 ++--
 arch/x86/kernel/fpu/init.c        | 8 ++++----
 5 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 6463258b4619..b23d5570a5f4 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -118,7 +118,6 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 	set_bit(bit, (unsigned long *)cpu_caps_set);	\
 } while (0)
 
-#define cpu_has_fpu		boot_cpu_has(X86_FEATURE_FPU)
 #define cpu_has_tsc		boot_cpu_has(X86_FEATURE_TSC)
 #define cpu_has_apic		boot_cpu_has(X86_FEATURE_APIC)
 #define cpu_has_fxsr		boot_cpu_has(X86_FEATURE_FXSR)
diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c
index 6adef9cac23e..bd9dcd6b712d 100644
--- a/arch/x86/kernel/cpu/cyrix.c
+++ b/arch/x86/kernel/cpu/cyrix.c
@@ -333,7 +333,7 @@ static void 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[(cpu_has_fpu ? 1 : 0)];
+			p = Cx486_name[!!boot_cpu_has(X86_FEATURE_FPU)];
 			break;
 
 		case 0xe:  /* a 486S A step */
diff --git a/arch/x86/kernel/fpu/bugs.c b/arch/x86/kernel/fpu/bugs.c
index dd9ca9b60ff3..224b5ec52195 100644
--- a/arch/x86/kernel/fpu/bugs.c
+++ b/arch/x86/kernel/fpu/bugs.c
@@ -66,6 +66,6 @@ void __init fpu__init_check_bugs(void)
 	 * kernel_fpu_begin/end() in check_fpu() relies on the patched
 	 * alternative instructions.
 	 */
-	if (cpu_has_fpu)
+	if (boot_cpu_has(X86_FEATURE_FPU))
 		check_fpu();
 }
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index b05aa68f88c0..0e7859f9aedc 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -217,7 +217,7 @@ static inline void fpstate_init_fstate(struct fregs_state *fp)
 
 void fpstate_init(union fpregs_state *state)
 {
-	if (!cpu_has_fpu) {
+	if (!static_cpu_has(X86_FEATURE_FPU)) {
 		fpstate_init_soft(&state->soft);
 		return;
 	}
@@ -237,7 +237,7 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
 	dst_fpu->fpregs_active = 0;
 	dst_fpu->last_cpu = -1;
 
-	if (!src_fpu->fpstate_active || !cpu_has_fpu)
+	if (!src_fpu->fpstate_active || !static_cpu_has(X86_FEATURE_FPU))
 		return 0;
 
 	WARN_ON_FPU(src_fpu != &current->thread.fpu);
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 9bbb332a71ff..3a84275f012e 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -38,13 +38,13 @@ static void fpu__init_cpu_generic(void)
 
 	cr0 = read_cr0();
 	cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
-	if (!cpu_has_fpu)
+	if (!boot_cpu_has(X86_FEATURE_FPU))
 		cr0 |= X86_CR0_EM;
 	write_cr0(cr0);
 
 	/* Flush out any pending x87 state: */
 #ifdef CONFIG_MATH_EMULATION
-	if (!cpu_has_fpu)
+	if (!boot_cpu_has(X86_FEATURE_FPU))
 		fpstate_init_soft(&current->thread.fpu.state.soft);
 	else
 #endif
@@ -89,7 +89,7 @@ static void fpu__init_system_early_generic(struct cpuinfo_x86 *c)
 	}
 
 #ifndef CONFIG_MATH_EMULATION
-	if (!cpu_has_fpu) {
+	if (!boot_cpu_has(X86_FEATURE_FPU)) {
 		pr_emerg("x86/fpu: Giving up, no FPU found and no math emulation present\n");
 		for (;;)
 			asm volatile("hlt");
@@ -212,7 +212,7 @@ static void __init fpu__init_system_xstate_size_legacy(void)
 	 * fpu__init_system_xstate().
 	 */
 
-	if (!cpu_has_fpu) {
+	if (!boot_cpu_has(X86_FEATURE_FPU)) {
 		/*
 		 * Disable xsave as we do not support it if i387
 		 * emulation is enabled.
-- 
2.7.3