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/kernel/fpu.c b/arch/mn10300/kernel/fpu.c
index e705f25..5f9c3fa 100644
--- a/arch/mn10300/kernel/fpu.c
+++ b/arch/mn10300/kernel/fpu.c
@@ -12,56 +12,19 @@
#include <asm/fpu.h>
#include <asm/elf.h>
#include <asm/exceptions.h>
+#include <asm/system.h>
+#ifdef CONFIG_LAZY_SAVE_FPU
struct task_struct *fpu_state_owner;
+#endif
/*
- * handle an exception due to the FPU being disabled
+ * error functions in FPU disabled exception
*/
-asmlinkage void fpu_disabled(struct pt_regs *regs, enum exception_code code)
+asmlinkage void fpu_disabled_in_kernel(struct pt_regs *regs)
{
- struct task_struct *tsk = current;
-
- if (!user_mode(regs))
- die_if_no_fixup("An FPU Disabled exception happened in"
- " kernel space\n",
- regs, code);
-
-#ifdef CONFIG_FPU
- preempt_disable();
-
- /* transfer the last process's FPU state to memory */
- if (fpu_state_owner) {
- fpu_save(&fpu_state_owner->thread.fpu_state);
- fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
- }
-
- /* the current process now owns the FPU state */
- fpu_state_owner = tsk;
- regs->epsw |= EPSW_FE;
-
- /* load the FPU with the current process's FPU state or invent a new
- * clean one if the process doesn't have one */
- if (is_using_fpu(tsk)) {
- fpu_restore(&tsk->thread.fpu_state);
- } else {
- fpu_init_state();
- set_using_fpu(tsk);
- }
-
- preempt_enable();
-#else
- {
- siginfo_t info;
-
- info.si_signo = SIGFPE;
- info.si_errno = 0;
- info.si_addr = (void *) tsk->thread.uregs->pc;
- info.si_code = FPE_FLTINV;
-
- force_sig_info(SIGFPE, &info, tsk);
- }
-#endif /* CONFIG_FPU */
+ die_if_no_fixup("An FPU Disabled exception happened in kernel space\n",
+ regs, EXCEP_FPU_DISABLED);
}
/*
@@ -71,15 +34,16 @@
*/
asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code)
{
- struct task_struct *tsk = fpu_state_owner;
+ struct task_struct *tsk = current;
siginfo_t info;
+ u32 fpcr;
if (!user_mode(regs))
die_if_no_fixup("An FPU Operation exception happened in"
" kernel space\n",
regs, code);
- if (!tsk)
+ if (!is_using_fpu(tsk))
die_if_no_fixup("An FPU Operation exception happened,"
" but the FPU is not in use",
regs, code);
@@ -89,48 +53,45 @@
info.si_addr = (void *) tsk->thread.uregs->pc;
info.si_code = FPE_FLTINV;
-#ifdef CONFIG_FPU
- {
- u32 fpcr;
+ unlazy_fpu(tsk);
- /* get FPCR (we need to enable the FPU whilst we do this) */
- asm volatile(" or %1,epsw \n"
-#ifdef CONFIG_MN10300_PROC_MN103E010
- " nop \n"
- " nop \n"
- " nop \n"
-#endif
- " fmov fpcr,%0 \n"
-#ifdef CONFIG_MN10300_PROC_MN103E010
- " nop \n"
- " nop \n"
- " nop \n"
-#endif
- " and %2,epsw \n"
- : "=&d"(fpcr)
- : "i"(EPSW_FE), "i"(~EPSW_FE)
- );
+ fpcr = tsk->thread.fpu_state.fpcr;
- if (fpcr & FPCR_EC_Z)
- info.si_code = FPE_FLTDIV;
- else if (fpcr & FPCR_EC_O)
- info.si_code = FPE_FLTOVF;
- else if (fpcr & FPCR_EC_U)
- info.si_code = FPE_FLTUND;
- else if (fpcr & FPCR_EC_I)
- info.si_code = FPE_FLTRES;
- }
-#endif
+ if (fpcr & FPCR_EC_Z)
+ info.si_code = FPE_FLTDIV;
+ else if (fpcr & FPCR_EC_O)
+ info.si_code = FPE_FLTOVF;
+ else if (fpcr & FPCR_EC_U)
+ info.si_code = FPE_FLTUND;
+ else if (fpcr & FPCR_EC_I)
+ info.si_code = FPE_FLTRES;
force_sig_info(SIGFPE, &info, tsk);
}
/*
+ * handle an FPU invalid_op exception
+ * - Derived from DO_EINFO() macro in arch/mn10300/kernel/traps.c
+ */
+asmlinkage void fpu_invalid_op(struct pt_regs *regs, enum exception_code code)
+{
+ siginfo_t info;
+
+ if (!user_mode(regs))
+ die_if_no_fixup("FPU invalid opcode", regs, code);
+
+ info.si_signo = SIGILL;
+ info.si_errno = 0;
+ info.si_code = ILL_COPROC;
+ info.si_addr = (void *) regs->pc;
+ force_sig_info(info.si_signo, &info, current);
+}
+
+/*
* save the FPU state to a signal context
*/
int fpu_setup_sigcontext(struct fpucontext *fpucontext)
{
-#ifdef CONFIG_FPU
struct task_struct *tsk = current;
if (!is_using_fpu(tsk))
@@ -142,11 +103,19 @@
*/
preempt_disable();
+#ifndef CONFIG_LAZY_SAVE_FPU
+ if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
+ fpu_save(&tsk->thread.fpu_state);
+ tsk->thread.uregs->epsw &= ~EPSW_FE;
+ tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
+ }
+#else /* !CONFIG_LAZY_SAVE_FPU */
if (fpu_state_owner == tsk) {
fpu_save(&tsk->thread.fpu_state);
fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
fpu_state_owner = NULL;
}
+#endif /* !CONFIG_LAZY_SAVE_FPU */
preempt_enable();
@@ -161,9 +130,6 @@
return -1;
return 1;
-#else
- return 0;
-#endif
}
/*
@@ -171,17 +137,23 @@
*/
void fpu_kill_state(struct task_struct *tsk)
{
-#ifdef CONFIG_FPU
/* disown anything left in the FPU */
preempt_disable();
+#ifndef CONFIG_LAZY_SAVE_FPU
+ if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
+ tsk->thread.uregs->epsw &= ~EPSW_FE;
+ tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
+ }
+#else /* !CONFIG_LAZY_SAVE_FPU */
if (fpu_state_owner == tsk) {
fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
fpu_state_owner = NULL;
}
+#endif /* !CONFIG_LAZY_SAVE_FPU */
preempt_enable();
-#endif
+
/* we no longer have a valid current FPU state */
clear_using_fpu(tsk);
}
@@ -195,8 +167,7 @@
int ret;
/* load up the old FPU state */
- ret = copy_from_user(&tsk->thread.fpu_state,
- fpucontext,
+ ret = copy_from_user(&tsk->thread.fpu_state, fpucontext,
min(sizeof(struct fpu_state_struct),
sizeof(struct fpucontext)));
if (!ret)