[PATCH 05/10] x86/cpufeature: Remove cpu_has_fpu

Borislav Petkov
2016-04-04T20:25:18Z

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@suse.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