[PATCH 024/208] x86/fpu: Split out the boot time FPU init code into fpu/init.c

Ingo Molnar
2015-05-05T17:01:53Z

Move boot time FPU initialization code into init.c, to better
isolate it into its own domain.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/fpu/Makefile | 2 +-
arch/x86/kernel/fpu/core.c | 88 ------------------------------------------------------------
arch/x86/kernel/fpu/init.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 94 insertions(+), 89 deletions(-)

diff --git a/arch/x86/kernel/fpu/Makefile b/arch/x86/kernel/fpu/Makefile
index 89fd66a4b3a1..50464a716b87 100644
--- a/arch/x86/kernel/fpu/Makefile
+++ b/arch/x86/kernel/fpu/Makefile
@@ -2,4 +2,4 @@
# Build rules for the FPU support code:
#

-obj-y += core.o xsave.o
+obj-y += init.o core.o xsave.o
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 01101553c6c1..9866a580952f 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -139,94 +139,6 @@ void fpu__save(struct task_struct *tsk)
}
EXPORT_SYMBOL_GPL(fpu__save);

-unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
-unsigned int xstate_size;
-EXPORT_SYMBOL_GPL(xstate_size);
-static struct i387_fxsave_struct fx_scratch;
-
-static void mxcsr_feature_mask_init(void)
-{
- unsigned long mask = 0;
-
- if (cpu_has_fxsr) {
- memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
- asm volatile("fxsave %0" : "+m" (fx_scratch));
- mask = fx_scratch.mxcsr_mask;
- if (mask == 0)
- mask = 0x0000ffbf;
- }
- mxcsr_feature_mask &= mask;
-}
-
-static void fpstate_xstate_init_size(void)
-{
- /*
- * Note that xstate_size might be overwriten later during
- * xsave_init().
- */
-
- if (!cpu_has_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);
- xstate_size = sizeof(struct i387_soft_struct);
- return;
- }
-
- if (cpu_has_fxsr)
- xstate_size = sizeof(struct i387_fxsave_struct);
- else
- xstate_size = sizeof(struct i387_fsave_struct);
-}
-
-/*
- * Called on the boot CPU at bootup to set up the initial FPU state that
- * is later cloned into all processes.
- *
- * Also called on secondary CPUs to set up the FPU state of their
- * idle threads.
- */
-void fpu__cpu_init(void)
-{
- unsigned long cr0;
- unsigned long cr4_mask = 0;
-
-#ifndef CONFIG_MATH_EMULATION
- if (!cpu_has_fpu) {
- pr_emerg("No FPU found and no math emulation present\n");
- pr_emerg("Giving up\n");
- for (;;)
- asm volatile("hlt");
- }
-#endif
- if (cpu_has_fxsr)
- cr4_mask |= X86_CR4_OSFXSR;
- if (cpu_has_xmm)
- cr4_mask |= X86_CR4_OSXMMEXCPT;
- if (cr4_mask)
- cr4_set_bits(cr4_mask);
-
- cr0 = read_cr0();
- cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
- if (!cpu_has_fpu)
- cr0 |= X86_CR0_EM;
- write_cr0(cr0);
-
- /*
- * fpstate_xstate_init_size() is only called once, to avoid overriding
- * 'xstate_size' during (secondary CPU) bootup or during CPU hotplug.
- */
- if (xstate_size == 0)
- fpstate_xstate_init_size();
-
- mxcsr_feature_mask_init();
- xsave_init();
- eager_fpu_init();
-}
-
void fpstate_init(struct fpu *fpu)
{
if (!cpu_has_fpu) {
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
new file mode 100644
index 000000000000..0a666298abbd
--- /dev/null
+++ b/arch/x86/kernel/fpu/init.c
@@ -0,0 +1,93 @@
+/*
+ * x86 FPU boot time init code
+ */
+#include <asm/fpu-internal.h>
+#include <asm/tlbflush.h>
+
+unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
+unsigned int xstate_size;
+EXPORT_SYMBOL_GPL(xstate_size);
+static struct i387_fxsave_struct fx_scratch;
+
+static void mxcsr_feature_mask_init(void)
+{
+ unsigned long mask = 0;
+
+ if (cpu_has_fxsr) {
+ memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
+ asm volatile("fxsave %0" : "+m" (fx_scratch));
+ mask = fx_scratch.mxcsr_mask;
+ if (mask == 0)
+ mask = 0x0000ffbf;
+ }
+ mxcsr_feature_mask &= mask;
+}
+
+static void fpstate_xstate_init_size(void)
+{
+ /*
+ * Note that xstate_size might be overwriten later during
+ * xsave_init().
+ */
+
+ if (!cpu_has_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);
+ xstate_size = sizeof(struct i387_soft_struct);
+ return;
+ }
+
+ if (cpu_has_fxsr)
+ xstate_size = sizeof(struct i387_fxsave_struct);
+ else
+ xstate_size = sizeof(struct i387_fsave_struct);
+}
+
+/*
+ * Called on the boot CPU at bootup to set up the initial FPU state that
+ * is later cloned into all processes.
+ *
+ * Also called on secondary CPUs to set up the FPU state of their
+ * idle threads.
+ */
+void fpu__cpu_init(void)
+{
+ unsigned long cr0;
+ unsigned long cr4_mask = 0;
+
+#ifndef CONFIG_MATH_EMULATION
+ if (!cpu_has_fpu) {
+ pr_emerg("No FPU found and no math emulation present\n");
+ pr_emerg("Giving up\n");
+ for (;;)
+ asm volatile("hlt");
+ }
+#endif
+ if (cpu_has_fxsr)
+ cr4_mask |= X86_CR4_OSFXSR;
+ if (cpu_has_xmm)
+ cr4_mask |= X86_CR4_OSXMMEXCPT;
+ if (cr4_mask)
+ cr4_set_bits(cr4_mask);
+
+ cr0 = read_cr0();
+ cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
+ if (!cpu_has_fpu)
+ cr0 |= X86_CR0_EM;
+ write_cr0(cr0);
+
+ /*
+ * fpstate_xstate_init_size() is only called once, to avoid overriding
+ * 'xstate_size' during (secondary CPU) bootup or during CPU hotplug.
+ */
+ if (xstate_size == 0)
+ fpstate_xstate_init_size();
+
+ mxcsr_feature_mask_init();
+ xsave_init();
+ eager_fpu_init();
+}
--
2.1.0