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authorPaul Mundt <lethal@linux-sh.org>2007-05-08 02:31:48 -0400
committerPaul Mundt <lethal@hera.kernel.org>2007-05-08 21:35:01 -0400
commit53f983a90d7908bcece51f86180c7c9b575a1e4d (patch)
treeda5914e6f18e8dd55563697de7339af2d99d9c18 /arch/sh/kernel/signal.c
parentbd0799977cb9b68aa6a39e9630aeea4778a58385 (diff)
sh: Fix PC adjustments for varying opcode length.
There are a few different cases for figuring out how to size the instruction. We read in the instruction located at regs->pc - 4 when rewinding the opcode to figure out if there's a 32-bit opcode before the faulting instruction, with a default of a - 2 adjustment on a mismatch. In practice this works for the cases where pc - 4 is just another 16-bit opcode, or we happen to have a 32-bit and a 16-bit immediately preceeding the pc value. In the cases where we aren't rewinding, this is much less ugly.. We also don't bother fixing up the places where we're explicitly dealing with 16-bit instructions, since this might lead to confusion regarding the encoding size possibilities on other CPU variants. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/signal.c')
-rw-r--r--arch/sh/kernel/signal.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/sh/kernel/signal.c b/arch/sh/kernel/signal.c
index d7d98d691c64..b32c35a7c0a3 100644
--- a/arch/sh/kernel/signal.c
+++ b/arch/sh/kernel/signal.c
@@ -500,7 +500,9 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
500 } 500 }
501 /* fallthrough */ 501 /* fallthrough */
502 case -ERESTARTNOINTR: 502 case -ERESTARTNOINTR:
503 regs->pc -= instruction_size(regs->pc); 503 regs->pc -= instruction_size(
504 ctrl_inw(regs->pc - 4));
505 break;
504 } 506 }
505 } else { 507 } else {
506 /* gUSA handling */ 508 /* gUSA handling */
@@ -516,7 +518,8 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
516 regs->regs[15] = regs->regs[1]; 518 regs->regs[15] = regs->regs[1];
517 if (regs->pc < regs->regs[0]) 519 if (regs->pc < regs->regs[0])
518 /* Go to rewind point #1 */ 520 /* Go to rewind point #1 */
519 regs->pc = regs->regs[0] + offset - 2; 521 regs->pc = regs->regs[0] + offset -
522 instruction_size(ctrl_inw(regs->pc-4));
520 } 523 }
521#ifdef CONFIG_PREEMPT 524#ifdef CONFIG_PREEMPT
522 local_irq_restore(flags); 525 local_irq_restore(flags);
@@ -600,9 +603,9 @@ static void do_signal(struct pt_regs *regs, unsigned int save_r0)
600 regs->regs[0] == -ERESTARTSYS || 603 regs->regs[0] == -ERESTARTSYS ||
601 regs->regs[0] == -ERESTARTNOINTR) { 604 regs->regs[0] == -ERESTARTNOINTR) {
602 regs->regs[0] = save_r0; 605 regs->regs[0] = save_r0;
603 regs->pc -= instruction_size(regs->pc); 606 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
604 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 607 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
605 regs->pc -= instruction_size(regs->pc); 608 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
606 regs->regs[3] = __NR_restart_syscall; 609 regs->regs[3] = __NR_restart_syscall;
607 } 610 }
608 } 611 }