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powerpc: Fix clearing of the FPSCR when invoking a signal handler

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As pointed out by Gary Byers, we were clearing the image of the FPSCR
(floating point status and control register) in the thread_struct before
copying it to the user stack when invoking a signal.  Thus the task
would see its FPSCR getting cleared when it took a signal.

While fixing it I noticed that our swapcontext system call was also
clearing FPSCR.  It shouldn't, so I fixed that too.

Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2005-11-14 21:55:15 +11:00
parent 493f25ef40
commit cc657f5392
2 changed files with 8 additions and 5 deletions
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7
arch/powerpc/kernel/signal_32.c
View file

@ -403,8 +403,6 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
ELF_NFPREG * sizeof(double)))
return 1;
current->thread.fpscr.val = 0; /* turn off all fp exceptions */
#ifdef CONFIG_ALTIVEC
/* save altivec registers */
if (current->thread.used_vr) {
@ -818,6 +816,9 @@ static int handle_rt_signal(unsigned long sig, struct k_sigaction *ka,
goto badframe;
regs->link = (unsigned long) frame->tramp;
}
current->thread.fpscr.val = 0; /* turn off all fp exceptions */
if (put_user(regs->gpr[1], (u32 __user *)newsp))
goto badframe;
regs->gpr[1] = newsp;
@ -1097,6 +1098,8 @@ static int handle_signal(unsigned long sig, struct k_sigaction *ka,
regs->link = (unsigned long) frame->mctx.tramp;
}
current->thread.fpscr.val = 0; /* turn off all fp exceptions */
if (put_user(regs->gpr[1], (u32 __user *)newsp))
goto badframe;
regs->gpr[1] = newsp;

6
arch/powerpc/kernel/signal_64.c
View file

@ -131,9 +131,6 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
flush_fp_to_thread(current);
/* Make sure signal doesn't get spurrious FP exceptions */
current->thread.fpscr.val = 0;
#ifdef CONFIG_ALTIVEC
err |= __put_user(v_regs, &sc->v_regs);
@ -423,6 +420,9 @@ static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
if (err)
goto badframe;
/* Make sure signal handler doesn't get spurious FP exceptions */
current->thread.fpscr.val = 0;
/* Set up to return from userspace. */
if (vdso64_rt_sigtramp && current->thread.vdso_base) {
regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;