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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2007-06-04 01:15:49 -0400
committerPaul Mackerras <paulus@samba.org>2007-06-14 08:29:57 -0400
commit22e38f29328296d9d4cc33e46fd32a63e807abaf (patch)
tree4cfea90671815ce87d5d0e896bb9f818565132c8 /arch/powerpc/kernel
parent791cc501d422be96d6e3098faf6471ba29f4dd33 (diff)
[POWERPC] Make syscall restart code more common
This patch moves the code in signal_32.c and signal_64.c for handling syscall restart into a common signal.c file and converge around a single implementation that is based on the 32 bits one, using trap, ccr and r3 rather than the special "result" field for deciding what to do. The "result" field is now pretty much deprecated. We still set it for the sake of whatever might rely on it in userland but we no longer use it's content. This, along with a previous patch that enables ptracers to write to "trap" and "orig_r3" should allow gdb to properly handle syscall restarting. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/Makefile3
-rw-r--r--arch/powerpc/kernel/signal.c65
-rw-r--r--arch/powerpc/kernel/signal.h16
-rw-r--r--arch/powerpc/kernel/signal_32.c28
-rw-r--r--arch/powerpc/kernel/signal_64.c59
5 files changed, 94 insertions, 77 deletions
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 08ce7de7c768..eb6a33e90d7e 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -12,7 +12,8 @@ endif
12 12
13obj-y := semaphore.o cputable.o ptrace.o syscalls.o \ 13obj-y := semaphore.o cputable.o ptrace.o syscalls.o \
14 irq.o align.o signal_32.o pmc.o vdso.o \ 14 irq.o align.o signal_32.o pmc.o vdso.o \
15 init_task.o process.o systbl.o idle.o 15 init_task.o process.o systbl.o idle.o \
16 signal.o
16obj-y += vdso32/ 17obj-y += vdso32/
17obj-$(CONFIG_PPC64) += setup_64.o binfmt_elf32.o sys_ppc32.o \ 18obj-$(CONFIG_PPC64) += setup_64.o binfmt_elf32.o sys_ppc32.o \
18 signal_64.o ptrace32.o \ 19 signal_64.o ptrace32.o \
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
new file mode 100644
index 000000000000..88a12544e8b1
--- /dev/null
+++ b/arch/powerpc/kernel/signal.c
@@ -0,0 +1,65 @@
1/*
2 * Common signal handling code for both 32 and 64 bits
3 *
4 * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
5 * Extracted from signal_32.c and signal_64.c
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file README.legal in the main directory of
9 * this archive for more details.
10 */
11
12#include <linux/ptrace.h>
13#include <linux/signal.h>
14#include <asm/unistd.h>
15
16void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
17 int has_handler)
18{
19 unsigned long ret = regs->gpr[3];
20 int restart = 1;
21
22 /* syscall ? */
23 if (TRAP(regs) != 0x0C00)
24 return;
25
26 /* error signalled ? */
27 if (!(regs->ccr & 0x10000000))
28 return;
29
30 switch (ret) {
31 case ERESTART_RESTARTBLOCK:
32 case ERESTARTNOHAND:
33 /* ERESTARTNOHAND means that the syscall should only be
34 * restarted if there was no handler for the signal, and since
35 * we only get here if there is a handler, we dont restart.
36 */
37 restart = !has_handler;
38 break;
39 case ERESTARTSYS:
40 /* ERESTARTSYS means to restart the syscall if there is no
41 * handler or the handler was registered with SA_RESTART
42 */
43 restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
44 break;
45 case ERESTARTNOINTR:
46 /* ERESTARTNOINTR means that the syscall should be
47 * called again after the signal handler returns.
48 */
49 break;
50 default:
51 return;
52 }
53 if (restart) {
54 if (ret == ERESTART_RESTARTBLOCK)
55 regs->gpr[0] = __NR_restart_syscall;
56 else
57 regs->gpr[3] = regs->orig_gpr3;
58 regs->nip -= 4;
59 regs->result = 0;
60 } else {
61 regs->result = -EINTR;
62 regs->gpr[3] = EINTR;
63 regs->ccr |= 0x10000000;
64 }
65}
diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h
new file mode 100644
index 000000000000..1e8dfb8620ad
--- /dev/null
+++ b/arch/powerpc/kernel/signal.h
@@ -0,0 +1,16 @@
1/*
2 * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
3 * Extracted from signal_32.c and signal_64.c
4 *
5 * This file is subject to the terms and conditions of the GNU General
6 * Public License. See the file README.legal in the main directory of
7 * this archive for more details.
8 */
9
10#ifndef _POWERPC_ARCH_SIGNAL_H
11#define _POWERPC_ARCH_SIGNAL_H
12
13extern void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
14 int has_handler);
15
16#endif /* _POWERPC_ARCH_SIGNAL_H */
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index dd1dca5bfa81..e5cc803476a1 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -51,6 +51,8 @@
51#include <asm/pgtable.h> 51#include <asm/pgtable.h>
52#endif 52#endif
53 53
54#include "signal.h"
55
54#undef DEBUG_SIG 56#undef DEBUG_SIG
55 57
56#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 58#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
@@ -1156,30 +1158,8 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
1156#ifdef CONFIG_PPC32 1158#ifdef CONFIG_PPC32
1157no_signal: 1159no_signal:
1158#endif 1160#endif
1159 if (TRAP(regs) == 0x0C00 /* System Call! */ 1161 /* Is there any syscall restart business here ? */
1160 && regs->ccr & 0x10000000 /* error signalled */ 1162 check_syscall_restart(regs, &ka, signr > 0);
1161 && ((ret = regs->gpr[3]) == ERESTARTSYS
1162 || ret == ERESTARTNOHAND || ret == ERESTARTNOINTR
1163 || ret == ERESTART_RESTARTBLOCK)) {
1164
1165 if (signr > 0
1166 && (ret == ERESTARTNOHAND || ret == ERESTART_RESTARTBLOCK
1167 || (ret == ERESTARTSYS
1168 && !(ka.sa.sa_flags & SA_RESTART)))) {
1169 /* make the system call return an EINTR error */
1170 regs->result = -EINTR;
1171 regs->gpr[3] = EINTR;
1172 /* note that the cr0.SO bit is already set */
1173 } else {
1174 regs->nip -= 4; /* Back up & retry system call */
1175 regs->result = 0;
1176 regs->trap = 0;
1177 if (ret == ERESTART_RESTARTBLOCK)
1178 regs->gpr[0] = __NR_restart_syscall;
1179 else
1180 regs->gpr[3] = regs->orig_gpr3;
1181 }
1182 }
1183 1163
1184 if (signr == 0) { 1164 if (signr == 0) {
1185 /* No signal to deliver -- put the saved sigmask back */ 1165 /* No signal to deliver -- put the saved sigmask back */
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 1ce0ae3f6ffc..5d2faf0fbf05 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -34,6 +34,8 @@
34#include <asm/syscalls.h> 34#include <asm/syscalls.h>
35#include <asm/vdso.h> 35#include <asm/vdso.h>
36 36
37#include "signal.h"
38
37#define DEBUG_SIG 0 39#define DEBUG_SIG 0
38 40
39#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 41#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
@@ -463,41 +465,6 @@ static int handle_signal(unsigned long sig, struct k_sigaction *ka,
463 return ret; 465 return ret;
464} 466}
465 467
466static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
467{
468 switch ((int)regs->result) {
469 case -ERESTART_RESTARTBLOCK:
470 case -ERESTARTNOHAND:
471 /* ERESTARTNOHAND means that the syscall should only be
472 * restarted if there was no handler for the signal, and since
473 * we only get here if there is a handler, we dont restart.
474 */
475 regs->result = -EINTR;
476 regs->gpr[3] = EINTR;
477 regs->ccr |= 0x10000000;
478 break;
479 case -ERESTARTSYS:
480 /* ERESTARTSYS means to restart the syscall if there is no
481 * handler or the handler was registered with SA_RESTART
482 */
483 if (!(ka->sa.sa_flags & SA_RESTART)) {
484 regs->result = -EINTR;
485 regs->gpr[3] = EINTR;
486 regs->ccr |= 0x10000000;
487 break;
488 }
489 /* fallthrough */
490 case -ERESTARTNOINTR:
491 /* ERESTARTNOINTR means that the syscall should be
492 * called again after the signal handler returns.
493 */
494 regs->gpr[3] = regs->orig_gpr3;
495 regs->nip -= 4;
496 regs->result = 0;
497 break;
498 }
499}
500
501/* 468/*
502 * Note that 'init' is a special process: it doesn't get signals it doesn't 469 * Note that 'init' is a special process: it doesn't get signals it doesn't
503 * want to handle. Thus you cannot kill init even with a SIGKILL even by 470 * want to handle. Thus you cannot kill init even with a SIGKILL even by
@@ -522,13 +489,13 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
522 oldset = &current->blocked; 489 oldset = &current->blocked;
523 490
524 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 491 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
492
493 /* Is there any syscall restart business here ? */
494 check_syscall_restart(regs, &ka, signr > 0);
495
525 if (signr > 0) { 496 if (signr > 0) {
526 int ret; 497 int ret;
527 498
528 /* Whee! Actually deliver the signal. */
529 if (TRAP(regs) == 0x0C00)
530 syscall_restart(regs, &ka);
531
532 /* 499 /*
533 * Reenable the DABR before delivering the signal to 500 * Reenable the DABR before delivering the signal to
534 * user space. The DABR will have been cleared if it 501 * user space. The DABR will have been cleared if it
@@ -537,6 +504,7 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
537 if (current->thread.dabr) 504 if (current->thread.dabr)
538 set_dabr(current->thread.dabr); 505 set_dabr(current->thread.dabr);
539 506
507 /* Whee! Actually deliver the signal. */
540 ret = handle_signal(signr, &ka, &info, oldset, regs); 508 ret = handle_signal(signr, &ka, &info, oldset, regs);
541 509
542 /* If a signal was successfully delivered, the saved sigmask is in 510 /* If a signal was successfully delivered, the saved sigmask is in
@@ -547,19 +515,6 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
547 return ret; 515 return ret;
548 } 516 }
549 517
550 if (TRAP(regs) == 0x0C00) { /* System Call! */
551 if ((int)regs->result == -ERESTARTNOHAND ||
552 (int)regs->result == -ERESTARTSYS ||
553 (int)regs->result == -ERESTARTNOINTR) {
554 regs->gpr[3] = regs->orig_gpr3;
555 regs->nip -= 4; /* Back up & retry system call */
556 regs->result = 0;
557 } else if ((int)regs->result == -ERESTART_RESTARTBLOCK) {
558 regs->gpr[0] = __NR_restart_syscall;
559 regs->nip -= 4;
560 regs->result = 0;
561 }
562 }
563 /* No signal to deliver -- put the saved sigmask back */ 518 /* No signal to deliver -- put the saved sigmask back */
564 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 519 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
565 clear_thread_flag(TIF_RESTORE_SIGMASK); 520 clear_thread_flag(TIF_RESTORE_SIGMASK);