MN10300: Make the FPU operate in non-lazy mode under SMP
Make the FPU operate in non-lazy mode under SMP so that when the process that
is currently using the FPU migrates to a different CPU, we don't have to ping
its previous CPU to flush the FPU context.
Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/arch/mn10300/include/asm/elf.h b/arch/mn10300/include/asm/elf.h
index e5fa97c..a30d220 100644
--- a/arch/mn10300/include/asm/elf.h
+++ b/arch/mn10300/include/asm/elf.h
@@ -47,8 +47,6 @@
u_int32_t fpcr;
} elf_fpregset_t;
-extern int dump_fpu(struct pt_regs *, elf_fpregset_t *);
-
/*
* This is used to ensure we don't load something for the wrong architecture
*/
diff --git a/arch/mn10300/include/asm/exceptions.h b/arch/mn10300/include/asm/exceptions.h
index 3f3826a..7d8080b 100644
--- a/arch/mn10300/include/asm/exceptions.h
+++ b/arch/mn10300/include/asm/exceptions.h
@@ -101,7 +101,6 @@
extern asmlinkage void raw_bus_error(void);
extern asmlinkage void double_fault(void);
extern asmlinkage int system_call(struct pt_regs *);
-extern asmlinkage void fpu_exception(struct pt_regs *, enum exception_code);
extern asmlinkage void nmi(struct pt_regs *, enum exception_code);
extern asmlinkage void uninitialised_exception(struct pt_regs *,
enum exception_code);
diff --git a/arch/mn10300/include/asm/fpu.h b/arch/mn10300/include/asm/fpu.h
index 64a2b83..b7625de 100644
--- a/arch/mn10300/include/asm/fpu.h
+++ b/arch/mn10300/include/asm/fpu.h
@@ -12,74 +12,125 @@
#ifndef _ASM_FPU_H
#define _ASM_FPU_H
-#include <asm/processor.h>
+#ifndef __ASSEMBLY__
+
+#include <linux/sched.h>
+#include <asm/exceptions.h>
#include <asm/sigcontext.h>
-#include <asm/user.h>
#ifdef __KERNEL__
-/* the task that owns the FPU state */
+extern asmlinkage void fpu_disabled(void);
+
+#ifdef CONFIG_FPU
+
+#ifdef CONFIG_LAZY_SAVE_FPU
+/* the task that currently owns the FPU state */
extern struct task_struct *fpu_state_owner;
+#endif
-#define set_using_fpu(tsk) \
-do { \
- (tsk)->thread.fpu_flags |= THREAD_USING_FPU; \
-} while (0)
+#if (THREAD_USING_FPU & ~0xff)
+#error THREAD_USING_FPU must be smaller than 0x100.
+#endif
-#define clear_using_fpu(tsk) \
-do { \
- (tsk)->thread.fpu_flags &= ~THREAD_USING_FPU; \
-} while (0)
+static inline void set_using_fpu(struct task_struct *tsk)
+{
+ asm volatile(
+ "bset %0,(0,%1)"
+ :
+ : "i"(THREAD_USING_FPU), "a"(&tsk->thread.fpu_flags)
+ : "memory", "cc");
+}
+
+static inline void clear_using_fpu(struct task_struct *tsk)
+{
+ asm volatile(
+ "bclr %0,(0,%1)"
+ :
+ : "i"(THREAD_USING_FPU), "a"(&tsk->thread.fpu_flags)
+ : "memory", "cc");
+}
#define is_using_fpu(tsk) ((tsk)->thread.fpu_flags & THREAD_USING_FPU)
-#define unlazy_fpu(tsk) \
-do { \
- preempt_disable(); \
- if (fpu_state_owner == (tsk)) \
- fpu_save(&tsk->thread.fpu_state); \
- preempt_enable(); \
-} while (0)
-
-#define exit_fpu() \
-do { \
- struct task_struct *__tsk = current; \
- preempt_disable(); \
- if (fpu_state_owner == __tsk) \
- fpu_state_owner = NULL; \
- preempt_enable(); \
-} while (0)
-
-#define flush_fpu() \
-do { \
- struct task_struct *__tsk = current; \
- preempt_disable(); \
- if (fpu_state_owner == __tsk) { \
- fpu_state_owner = NULL; \
- __tsk->thread.uregs->epsw &= ~EPSW_FE; \
- } \
- preempt_enable(); \
- clear_using_fpu(__tsk); \
-} while (0)
-
-extern asmlinkage void fpu_init_state(void);
extern asmlinkage void fpu_kill_state(struct task_struct *);
-extern asmlinkage void fpu_disabled(struct pt_regs *, enum exception_code);
extern asmlinkage void fpu_exception(struct pt_regs *, enum exception_code);
-
-#ifdef CONFIG_FPU
+extern asmlinkage void fpu_invalid_op(struct pt_regs *, enum exception_code);
+extern asmlinkage void fpu_init_state(void);
extern asmlinkage void fpu_save(struct fpu_state_struct *);
-extern asmlinkage void fpu_restore(struct fpu_state_struct *);
-#else
-#define fpu_save(a)
-#define fpu_restore(a)
-#endif /* CONFIG_FPU */
-
-/*
- * signal frame handlers
- */
extern int fpu_setup_sigcontext(struct fpucontext *buf);
extern int fpu_restore_sigcontext(struct fpucontext *buf);
+static inline void unlazy_fpu(struct task_struct *tsk)
+{
+ preempt_disable();
+#ifndef CONFIG_LAZY_SAVE_FPU
+ if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
+ fpu_save(&tsk->thread.fpu_state);
+ tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
+ tsk->thread.uregs->epsw &= ~EPSW_FE;
+ }
+#else
+ if (fpu_state_owner == tsk)
+ fpu_save(&tsk->thread.fpu_state);
+#endif
+ preempt_enable();
+}
+
+static inline void exit_fpu(void)
+{
+#ifdef CONFIG_LAZY_SAVE_FPU
+ struct task_struct *tsk = current;
+
+ preempt_disable();
+ if (fpu_state_owner == tsk)
+ fpu_state_owner = NULL;
+ preempt_enable();
+#endif
+}
+
+static inline void flush_fpu(void)
+{
+ struct task_struct *tsk = current;
+
+ preempt_disable();
+#ifndef CONFIG_LAZY_SAVE_FPU
+ if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
+ tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
+ tsk->thread.uregs->epsw &= ~EPSW_FE;
+ }
+#else
+ if (fpu_state_owner == tsk) {
+ fpu_state_owner = NULL;
+ tsk->thread.uregs->epsw &= ~EPSW_FE;
+ }
+#endif
+ preempt_enable();
+ clear_using_fpu(tsk);
+}
+
+#else /* CONFIG_FPU */
+
+extern asmlinkage
+void unexpected_fpu_exception(struct pt_regs *, enum exception_code);
+#define fpu_invalid_op unexpected_fpu_exception
+#define fpu_exception unexpected_fpu_exception
+
+struct task_struct;
+struct fpu_state_struct;
+static inline bool is_using_fpu(struct task_struct *tsk) { return false; }
+static inline void set_using_fpu(struct task_struct *tsk) {}
+static inline void clear_using_fpu(struct task_struct *tsk) {}
+static inline void fpu_init_state(void) {}
+static inline void fpu_save(struct fpu_state_struct *s) {}
+static inline void fpu_kill_state(struct task_struct *tsk) {}
+static inline void unlazy_fpu(struct task_struct *tsk) {}
+static inline void exit_fpu(void) {}
+static inline void flush_fpu(void) {}
+static inline int fpu_setup_sigcontext(struct fpucontext *buf) { return 0; }
+static inline int fpu_restore_sigcontext(struct fpucontext *buf) { return 0; }
+#endif /* CONFIG_FPU */
+
#endif /* __KERNEL__ */
+#endif /* !__ASSEMBLY__ */
#endif /* _ASM_FPU_H */
diff --git a/arch/mn10300/include/asm/processor.h b/arch/mn10300/include/asm/processor.h
index fd96c18..0032fc7 100644
--- a/arch/mn10300/include/asm/processor.h
+++ b/arch/mn10300/include/asm/processor.h
@@ -95,6 +95,7 @@
struct pt_regs *__frame;
unsigned long fpu_flags;
#define THREAD_USING_FPU 0x00000001 /* T if this task is using the FPU */
+#define THREAD_HAS_FPU 0x00000002 /* T if this task owns the FPU right now */
struct fpu_state_struct fpu_state;
};
diff --git a/arch/mn10300/include/asm/system.h b/arch/mn10300/include/asm/system.h
index 9f7c7e1..3c272a1 100644
--- a/arch/mn10300/include/asm/system.h
+++ b/arch/mn10300/include/asm/system.h
@@ -19,6 +19,21 @@
#include <linux/kernel.h>
#include <linux/irqflags.h>
+#if !defined(CONFIG_LAZY_SAVE_FPU)
+struct fpu_state_struct;
+extern asmlinkage void fpu_save(struct fpu_state_struct *);
+#define switch_fpu(prev, next) \
+ do { \
+ if ((prev)->thread.fpu_flags & THREAD_HAS_FPU) { \
+ (prev)->thread.fpu_flags &= ~THREAD_HAS_FPU; \
+ (prev)->thread.uregs->epsw &= ~EPSW_FE; \
+ fpu_save(&(prev)->thread.fpu_state); \
+ } \
+ } while (0)
+#else
+#define switch_fpu(prev, next) do {} while (0)
+#endif
+
struct task_struct;
struct thread_struct;
@@ -30,6 +45,7 @@
/* context switching is now performed out-of-line in switch_to.S */
#define switch_to(prev, next, last) \
do { \
+ switch_fpu(prev, next); \
current->thread.wchan = (u_long) __builtin_return_address(0); \
(last) = __switch_to(&(prev)->thread, &(next)->thread, (prev)); \
mb(); \