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[MIPS] FPU ownership management & preemption fixes

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Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Atsushi Nemoto
2007-03-10 01:07:45 +09:00
committed by Ralf Baechle
parent c6a2f46793
commit 53dc80287d
10 changed files with 126 additions and 105 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
arch/mips/kernel/r2300_switch.S
View File

@@ -49,8 +49,7 @@ LEAF(resume)
#ifndef CONFIG_CPU_HAS_LLSC
sw zero, ll_bit
#endif
mfc0 t1, CP0_STATUS
sw t1, THREAD_STATUS(a0)
mfc0 t2, CP0_STATUS
cpu_save_nonscratch a0
sw ra, THREAD_REG31(a0)
@@ -60,8 +59,8 @@ LEAF(resume)
lw t3, TASK_THREAD_INFO(a0)
lw t0, TI_FLAGS(t3)
li t1, _TIF_USEDFPU
and t2, t0, t1
beqz t2, 1f
and t1, t0
beqz t1, 1f
nor t1, zero, t1
and t0, t0, t1
@@ -74,10 +73,13 @@ LEAF(resume)
li t1, ~ST0_CU1
and t0, t0, t1
sw t0, ST_OFF(t3)
/* clear thread_struct CU1 bit */
and t2, t1
fpu_save_single a0, t0 # clobbers t0
1:
sw t2, THREAD_STATUS(a0)
/*
* The order of restoring the registers takes care of the race
* updating $28, $29 and kernelsp without disabling ints.

10
arch/mips/kernel/r4k_switch.S
View File

@@ -48,8 +48,7 @@
#ifndef CONFIG_CPU_HAS_LLSC
sw zero, ll_bit
#endif
mfc0 t1, CP0_STATUS
LONG_S t1, THREAD_STATUS(a0)
mfc0 t2, CP0_STATUS
cpu_save_nonscratch a0
LONG_S ra, THREAD_REG31(a0)
@@ -59,8 +58,8 @@
PTR_L t3, TASK_THREAD_INFO(a0)
LONG_L t0, TI_FLAGS(t3)
li t1, _TIF_USEDFPU
and t2, t0, t1
beqz t2, 1f
and t1, t0
beqz t1, 1f
nor t1, zero, t1
and t0, t0, t1
@@ -73,10 +72,13 @@
li t1, ~ST0_CU1
and t0, t0, t1
LONG_S t0, ST_OFF(t3)
/* clear thread_struct CU1 bit */
and t2, t1
fpu_save_double a0 t0 t1 # c0_status passed in t0
# clobbers t1
1:
LONG_S t2, THREAD_STATUS(a0)
/*
* The order of restoring the registers takes care of the race

29
arch/mips/kernel/signal.c
View File

@@ -82,6 +82,7 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
int err = 0;
int i;
unsigned int used_math;
err |= __put_user(regs->cp0_epc, &sc->sc_pc);
@@ -104,22 +105,18 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
}
err |= __put_user(!!used_math(), &sc->sc_used_math);
used_math = !!used_math();
err |= __put_user(used_math, &sc->sc_used_math);
if (used_math()) {
if (used_math) {
/*
* Save FPU state to signal context. Signal handler
* will "inherit" current FPU state.
*/
preempt_disable();
if (!is_fpu_owner()) {
own_fpu();
restore_fp(current);
}
own_fpu(1);
enable_fp_in_kernel();
err |= save_fp_context(sc);
preempt_enable();
disable_fp_in_kernel();
}
return err;
}
@@ -188,20 +185,18 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
err |= __get_user(used_math, &sc->sc_used_math);
conditional_used_math(used_math);
preempt_disable();
if (used_math()) {
if (used_math) {
/* restore fpu context if we have used it before */
own_fpu();
own_fpu(0);
enable_fp_in_kernel();
if (!err)
err = check_and_restore_fp_context(sc);
disable_fp_in_kernel();
} else {
/* signal handler may have used FPU. Give it up. */
lose_fpu();
lose_fpu(0);
}
preempt_enable();
return err;
}

29
arch/mips/kernel/signal32.c
View File

@@ -181,6 +181,7 @@ static int setup_sigcontext32(struct pt_regs *regs,
{
int err = 0;
int i;
u32 used_math;
err |= __put_user(regs->cp0_epc, &sc->sc_pc);
@@ -200,22 +201,18 @@ static int setup_sigcontext32(struct pt_regs *regs,
err |= __put_user(mflo3(), &sc->sc_lo3);
}
err |= __put_user(!!used_math(), &sc->sc_used_math);
used_math = !!used_math();
err |= __put_user(used_math, &sc->sc_used_math);
if (used_math()) {
if (used_math) {
/*
* Save FPU state to signal context. Signal handler
* will "inherit" current FPU state.
*/
preempt_disable();
if (!is_fpu_owner()) {
own_fpu();
restore_fp(current);
}
own_fpu(1);
enable_fp_in_kernel();
err |= save_fp_context32(sc);
preempt_enable();
disable_fp_in_kernel();
}
return err;
}
@@ -262,20 +259,18 @@ static int restore_sigcontext32(struct pt_regs *regs,
err |= __get_user(used_math, &sc->sc_used_math);
conditional_used_math(used_math);
preempt_disable();
if (used_math()) {
if (used_math) {
/* restore fpu context if we have used it before */
own_fpu();
own_fpu(0);
enable_fp_in_kernel();
if (!err)
err = check_and_restore_fp_context32(sc);
disable_fp_in_kernel();
} else {
/* signal handler may have used FPU. Give it up. */
lose_fpu();
lose_fpu(0);
}
preempt_enable();
return err;
}

84
arch/mips/kernel/traps.c
View File

@@ -610,16 +610,6 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
if (fcr31 & FPU_CSR_UNI_X) {
int sig;
preempt_disable();
#ifdef CONFIG_PREEMPT
if (!is_fpu_owner()) {
/* We might lose fpu before disabling preempt... */
own_fpu();
BUG_ON(!used_math());
restore_fp(current);
}
#endif
/*
* Unimplemented operation exception. If we've got the full
* software emulator on-board, let's use it...
@@ -630,18 +620,12 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
* register operands before invoking the emulator, which seems
* a bit extreme for what should be an infrequent event.
*/
save_fp(current);
/* Ensure 'resume' not overwrite saved fp context again. */
lose_fpu();
preempt_enable();
lose_fpu(1);
/* Run the emulator */
sig = fpu_emulator_cop1Handler (regs, &current->thread.fpu, 1);
preempt_disable();
own_fpu(); /* Using the FPU again. */
/*
* We can't allow the emulated instruction to leave any of
* the cause bit set in $fcr31.
@@ -649,9 +633,7 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
/* Restore the hardware register state */
restore_fp(current);
preempt_enable();
own_fpu(1); /* Using the FPU again. */
/* If something went wrong, signal */
if (sig)
@@ -775,12 +757,11 @@ asmlinkage void do_cpu(struct pt_regs *regs)
{
unsigned int cpid;
die_if_kernel("do_cpu invoked from kernel context!", regs);
cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
switch (cpid) {
case 0:
die_if_kernel("do_cpu invoked from kernel context!", regs);
if (!cpu_has_llsc)
if (!simulate_llsc(regs))
return;
@@ -791,21 +772,30 @@ asmlinkage void do_cpu(struct pt_regs *regs)
break;
case 1:
preempt_disable();
own_fpu();
if (used_math()) { /* Using the FPU again. */
restore_fp(current);
} else { /* First time FPU user. */
if (!test_thread_flag(TIF_ALLOW_FP_IN_KERNEL))
die_if_kernel("do_cpu invoked from kernel context!",
regs);
if (used_math()) /* Using the FPU again. */
own_fpu(1);
else { /* First time FPU user. */
init_fpu();
set_used_math();
}
if (cpu_has_fpu) {
preempt_enable();
if (raw_cpu_has_fpu) {
if (test_thread_flag(TIF_ALLOW_FP_IN_KERNEL)) {
local_irq_disable();
if (cpu_has_fpu)
regs->cp0_status |= ST0_CU1;
/*
* We must return without enabling
* interrupts to ensure keep FPU
* ownership until resume.
*/
return;
}
} else {
int sig;
preempt_enable();
sig = fpu_emulator_cop1Handler(regs,
&current->thread.fpu, 0);
if (sig)
@@ -1259,26 +1249,26 @@ static inline void mips_srs_init(void)
/*
* This is used by native signal handling
*/
asmlinkage int (*save_fp_context)(struct sigcontext *sc);
asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
extern asmlinkage int _save_fp_context(struct sigcontext *sc);
extern asmlinkage int _restore_fp_context(struct sigcontext *sc);
extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);
extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
#ifdef CONFIG_SMP
static int smp_save_fp_context(struct sigcontext *sc)
static int smp_save_fp_context(struct sigcontext __user *sc)
{
return cpu_has_fpu
return raw_cpu_has_fpu
? _save_fp_context(sc)
: fpu_emulator_save_context(sc);
}
static int smp_restore_fp_context(struct sigcontext *sc)
static int smp_restore_fp_context(struct sigcontext __user *sc)
{
return cpu_has_fpu
return raw_cpu_has_fpu
? _restore_fp_context(sc)
: fpu_emulator_restore_context(sc);
}
@@ -1306,14 +1296,14 @@ static inline void signal_init(void)
/*
* 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);
asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
extern asmlinkage int _save_fp_context32(struct sigcontext32 *sc);
extern asmlinkage int _restore_fp_context32(struct sigcontext32 *sc);
extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 *sc);
extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 *sc);
extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
static inline void signal32_init(void)
{