>>>>> On Thu, 13 Oct 2005 15:04:15 +0100, Ralf Baechle <ralf@xxxxxxxxxxxxxx> said:
ralf> I think much of the 87d54649f67d8ffe0a8d8176de8c210a6c4bb4a7
ralf> preemption patch is flawed and the problem you were trying to
ralf> fix are in part just caused by it.
Well... the patch fixed some problem because preempt_disable/enable is
actually needed for lazy fpu switch, but some of the fixes was wrong
(as I wrote at that time ;-)).
Anyway, I create an another patch by rewriting
restore_fp_context/save_fp_context. While thread.fpu.hard and
thread.fpu.soft are completely same, things are quite simple.
Description:
The setup_sigcontect/restore_sigcontext might sleep on
put_user/get_user with preemption disabled (i.e. atomic context).
Sleeping in atomic context is not allowed. This patch fixes this
problem rewriting restore_fp_context/save_fp_context.
fp context saving path is:
BEFORE: (thread.fpu -> ) real FPU -> sigcontext
AFTER: (real FPU -> ) thread.fpu -> sigcontext
arch/mips/kernel/signal-common.h | 56 +++++++++++++++++++++------
arch/mips/kernel/signal32.c | 54 ++++++++++++++++++++------
arch/mips/kernel/traps.c | 54 --------------------------
arch/mips/math-emu/kernel_linkage.c | 73 ------------------------------------ include/asm-mips/fpu.h | 9 ----
5 files changed, 86 insertions(+), 160 deletions(-)
Then we can remove all arch/mips/kernel/*_fpu.S and some (all?) SC_
symbols from asm-offset.c file.
Signed-off-by: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
--- a/arch/mips/kernel/signal-common.h
+++ b/arch/mips/kernel/signal-common.h
@@ -10,6 +10,42 @@
#include <linux/config.h>
+/*
+ * Emulator context save/restore to/from a signal context
+ * presumed to be on the user stack, and therefore accessed
+ * with appropriate macros from uaccess.h
+ */
+
+static inline int save_fp_context(struct sigcontext *sc)
+{
+ int i;
+ int err = 0;
+
+ for (i = 0; i < 32; i++) {
+ err |=
+ __put_user(current->thread.fpu.soft.fpr[i],
+ &sc->sc_fpregs[i]);
+ }
+ err |= __put_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
+
+ return err;
+}
+
+static inline int restore_fp_context(struct sigcontext *sc)
+{
+ int i;
+ int err = 0;
+
+ for (i = 0; i < 32; i++) {
+ err |=
+ __get_user(current->thread.fpu.soft.fpr[i],
+ &sc->sc_fpregs[i]);
+ }
+ err |= __get_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
+
+ return err;
+}
+
static inline int
setup_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
{
@@ -68,15 +104,14 @@ setup_sigcontext(struct pt_regs *regs, s
* current FPU state.
*/
preempt_disable();
-
- if (!is_fpu_owner()) {
- own_fpu();
- restore_fp(current);
+ if (is_fpu_owner()) {
+ /* save current context to task_struct */
+ save_fp(current);
+ /* no need to call lose_fpu here. */
}
- err |= save_fp_context(sc);
-
preempt_enable();
+ err |= save_fp_context(sc);
out:
return err;
}
@@ -138,19 +173,16 @@ restore_sigcontext(struct pt_regs *regs,
err |= __get_user(used_math, &sc->sc_used_math);
conditional_used_math(used_math);
+ /* signal handler may have used FPU. Give it up. */
preempt_disable();
+ lose_fpu();
+ preempt_enable();
if (used_math()) {
/* restore fpu context if we have used it before */
- own_fpu();
err |= restore_fp_context(sc);
- } else {
- /* signal handler may have used FPU. Give it up. */
- lose_fpu();
}
- preempt_enable();
-
return err;
}
diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -335,6 +335,40 @@ asmlinkage int sys32_sigaltstack(nabi_no
return ret;
}
+/*
+ * This is the o32 version
+ */
+
+static inline int save_fp_context32(struct sigcontext32 *sc)
+{
+ int i;
+ int err = 0;
+
+ for (i = 0; i < 32; i+=2) {
+ err |=
+ __put_user(current->thread.fpu.soft.fpr[i],
+ &sc->sc_fpregs[i]);
+ }
+ err |= __put_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
+
+ return err;
+}
+
+static inline int restore_fp_context32(struct sigcontext32 *sc)
+{
+ int i;
+ int err = 0;
+
+ for (i = 0; i < 32; i+=2) {
+ err |=
+ __get_user(current->thread.fpu.soft.fpr[i],
+ &sc->sc_fpregs[i]);
+ }
+ err |= __get_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
+
+ return err;
+}
+
static int restore_sigcontext32(struct pt_regs *regs, struct sigcontext32 *sc)
{
u32 used_math;
@@ -376,19 +410,16 @@ static int restore_sigcontext32(struct p
err |= __get_user(used_math, &sc->sc_used_math);
conditional_used_math(used_math);
+ /* signal handler may have used FPU. Give it up. */
preempt_disable();
+ lose_fpu();
+ preempt_enable();
if (used_math()) {
/* restore fpu context if we have used it before */
- own_fpu();
err |= restore_fp_context32(sc);
- } else {
- /* signal handler may have used FPU. Give it up. */
- lose_fpu();
}
- preempt_enable();
-
return err;
}
@@ -609,15 +640,14 @@ static inline int setup_sigcontext32(str
* current FPU state.
*/
preempt_disable();
-
- if (!is_fpu_owner()) {
- own_fpu();
- restore_fp(current);
+ if (is_fpu_owner()) {
+ /* save current context to task_struct */
+ save_fp(current);
+ /* no need to call lose_fpu here. */
}
- err |= save_fp_context32(sc);
-
preempt_enable();
+ err |= save_fp_context32(sc);
out:
return err;
}
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1098,55 +1098,6 @@ void *set_vi_handler (int n, void *addr)
}
#endif
-/*
- * This is used by native signal handling
- */
-asmlinkage int (*save_fp_context)(struct sigcontext *sc);
-asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
-
-extern asmlinkage int _save_fp_context(struct sigcontext *sc);
-extern asmlinkage int _restore_fp_context(struct sigcontext *sc);
-
-extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
-extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);
-
-static inline void signal_init(void)
-{
- if (cpu_has_fpu) {
- save_fp_context = _save_fp_context;
- restore_fp_context = _restore_fp_context;
- } else {
- save_fp_context = fpu_emulator_save_context;
- restore_fp_context = fpu_emulator_restore_context;
- }
-}
-
-#ifdef CONFIG_MIPS32_COMPAT
-
-/*
- * This is used by 32-bit signal stuff on the 64-bit kernel
- */
-asmlinkage int (*save_fp_context32)(struct sigcontext32 *sc);
-asmlinkage int (*restore_fp_context32)(struct sigcontext32 *sc);
-
-extern asmlinkage int _save_fp_context32(struct sigcontext32 *sc);
-extern asmlinkage int _restore_fp_context32(struct sigcontext32 *sc);
-
-extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 *sc);
-extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 *sc);
-
-static inline void signal32_init(void)
-{
- if (cpu_has_fpu) {
- save_fp_context32 = _save_fp_context32;
- restore_fp_context32 = _restore_fp_context32;
- } else {
- save_fp_context32 = fpu_emulator_save_context32;
- restore_fp_context32 = fpu_emulator_restore_context32;
- }
-}
-#endif
-
extern void cpu_cache_init(void);
extern void tlb_init(void);
@@ -1350,10 +1301,5 @@ void __init trap_init(void)
else
memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
- signal_init();
-#ifdef CONFIG_MIPS32_COMPAT
- signal32_init();
-#endif
-
flush_icache_range(ebase, ebase + 0x400);
}
diff --git a/arch/mips/math-emu/kernel_linkage.c b/arch/mips/math-emu/kernel_linkage.c
--- a/arch/mips/math-emu/kernel_linkage.c
+++ b/arch/mips/math-emu/kernel_linkage.c
@@ -44,76 +44,3 @@ void fpu_emulator_init_fpu(void)
current->thread.fpu.soft.fpr[i] = SIGNALLING_NAN;
}
}
-
-
-/*
- * Emulator context save/restore to/from a signal context
- * presumed to be on the user stack, and therefore accessed
- * with appropriate macros from uaccess.h
- */
-
-int fpu_emulator_save_context(struct sigcontext *sc)
-{
- int i;
- int err = 0;
-
- for (i = 0; i < 32; i++) {
- err |=
- __put_user(current->thread.fpu.soft.fpr[i],
- &sc->sc_fpregs[i]);
- }
- err |= __put_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
-
- return err;
-}
-
-int fpu_emulator_restore_context(struct sigcontext *sc)
-{
- int i;
- int err = 0;
-
- for (i = 0; i < 32; i++) {
- err |=
- __get_user(current->thread.fpu.soft.fpr[i],
- &sc->sc_fpregs[i]);
- }
- err |= __get_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
-
- return err;
-}
-
-#ifdef CONFIG_64BIT
-/*
- * This is the o32 version
- */
-
-int fpu_emulator_save_context32(struct sigcontext32 *sc)
-{
- int i;
- int err = 0;
-
- for (i = 0; i < 32; i+=2) {
- err |=
- __put_user(current->thread.fpu.soft.fpr[i],
- &sc->sc_fpregs[i]);
- }
- err |= __put_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
-
- return err;
-}
-
-int fpu_emulator_restore_context32(struct sigcontext32 *sc)
-{
- int i;
- int err = 0;
-
- for (i = 0; i < 32; i+=2) {
- err |=
- __get_user(current->thread.fpu.soft.fpr[i],
- &sc->sc_fpregs[i]);
- }
- err |= __get_user(current->thread.fpu.soft.fcr31, &sc->sc_fpc_csr);
-
- return err;
-}
-#endif
diff --git a/include/asm-mips/fpu.h b/include/asm-mips/fpu.h
--- a/include/asm-mips/fpu.h
+++ b/include/asm-mips/fpu.h
@@ -21,15 +21,6 @@
#include <asm/processor.h>
#include <asm/current.h>
-struct sigcontext;
-struct sigcontext32;
-
-extern asmlinkage int (*save_fp_context)(struct sigcontext *sc);
-extern asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
-
-extern asmlinkage int (*save_fp_context32)(struct sigcontext32 *sc);
-extern asmlinkage int (*restore_fp_context32)(struct sigcontext32 *sc);
-
extern void fpu_emulator_init_fpu(void);
extern void _init_fpu(void);
extern void _save_fp(struct task_struct *);
