[PATCH] Fix sparc TIF_USEDFPU flag atomicity

From: Mathieu Desnoyers
Date: Thu Mar 08 2007 - 22:12:47 EST


Fix sparc TIF_USEDFPU flag atomicity

Non atomic update of TIF can be very dangerous, except at thread structure
creation time. Here I standardize the TIF_USEDFPU usage of the sparc arch.

Applies on 2.6.20.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>

--- a/arch/sparc/kernel/process.c
+++ b/arch/sparc/kernel/process.c
@@ -348,7 +348,7 @@ void exit_thread(void)
#ifndef CONFIG_SMP
if(last_task_used_math == current) {
#else
- if(current_thread_info()->flags & _TIF_USEDFPU) {
+ if(test_tsk_thread_flag(current, TIF_USEDFPU)) {
#endif
/* Keep process from leaving FPU in a bogon state. */
put_psr(get_psr() | PSR_EF);
@@ -357,7 +357,7 @@ void exit_thread(void)
#ifndef CONFIG_SMP
last_task_used_math = NULL;
#else
- current_thread_info()->flags &= ~_TIF_USEDFPU;
+ clear_tsk_thread_flag(current, TIF_USEDFPU);
#endif
}
}
@@ -371,7 +371,7 @@ void flush_thread(void)
#ifndef CONFIG_SMP
if(last_task_used_math == current) {
#else
- if(current_thread_info()->flags & _TIF_USEDFPU) {
+ if(test_tsk_thread_flag(current, TIF_USEDFPU)) {
#endif
/* Clean the fpu. */
put_psr(get_psr() | PSR_EF);
@@ -380,7 +380,7 @@ void flush_thread(void)
#ifndef CONFIG_SMP
last_task_used_math = NULL;
#else
- current_thread_info()->flags &= ~_TIF_USEDFPU;
+ clear_tsk_thread_flag(current, TIF_USEDFPU);
#endif
}

@@ -466,13 +466,13 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
#ifndef CONFIG_SMP
if(last_task_used_math == current) {
#else
- if(current_thread_info()->flags & _TIF_USEDFPU) {
+ if(test_tsk_thread_flag(current, TIF_USEDFPU)) {
#endif
put_psr(get_psr() | PSR_EF);
fpsave(&p->thread.float_regs[0], &p->thread.fsr,
&p->thread.fpqueue[0], &p->thread.fpqdepth);
#ifdef CONFIG_SMP
- current_thread_info()->flags &= ~_TIF_USEDFPU;
+ clear_tsk_thread_flag(current, TIF_USEDFPU);
#endif
}

@@ -609,13 +609,13 @@ int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
return 1;
}
#ifdef CONFIG_SMP
- if (current_thread_info()->flags & _TIF_USEDFPU) {
+ if (test_tsk_thread_flag(current, TIF_USEDFPU)) {
put_psr(get_psr() | PSR_EF);
fpsave(&current->thread.float_regs[0], &current->thread.fsr,
&current->thread.fpqueue[0], &current->thread.fpqdepth);
if (regs != NULL) {
regs->psr &= ~(PSR_EF);
- current_thread_info()->flags &= ~(_TIF_USEDFPU);
+ clear_tsk_thread_flag(current, TIF_USEDFPU);
}
}
#else
diff --git a/arch/sparc/kernel/traps.c b/arch/sparc/kernel/traps.c
index 6a70d21..7a7ad05 100644
--- a/arch/sparc/kernel/traps.c
+++ b/arch/sparc/kernel/traps.c
@@ -259,7 +259,7 @@ void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
} else {
fpload(&current->thread.float_regs[0], &current->thread.fsr);
}
- current_thread_info()->flags |= _TIF_USEDFPU;
+ set_tsk_thread_flag(current, TIF_USEDFPU);
#endif
}

@@ -290,7 +290,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
#ifndef CONFIG_SMP
if(!fpt) {
#else
- if(!(task_thread_info(fpt)->flags & _TIF_USEDFPU)) {
+ if(!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
#endif
fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
regs->psr &= ~PSR_EF;
@@ -333,7 +333,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
/* nope, better SIGFPE the offending process... */

#ifdef CONFIG_SMP
- task_thread_info(fpt)->flags &= ~_TIF_USEDFPU;
+ clear_tsk_thread_flag(fpt, TIF_USEDFPU);
#endif
if(psr & PSR_PS) {
/* The first fsr store/load we tried trapped,
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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