arm: new way of handling ERESTART_RESTARTBLOCK

new "syscall start" flag; handled in syscall_trace() by switching
syscall number to that of syscall_restart(2).  Restarts of that
kind (ERESTART_RESTARTBLOCK) are handled by setting that bit;
syscall number is not modified until the actual call.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 2d0cfc2ba23c5bab034f6389ae9b80476bc5addb..680c623a3d1f40444ec62477dc849af7111c1b47 100644 (file)
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -148,6 +148,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
 #define TIF_NOTIFY_RESUME      2       /* callback before returning to user */
 #define TIF_SYSCALL_TRACE      8
 #define TIF_SYSCALL_AUDIT      9
+#define TIF_SYSCALL_RESTARTSYS 10
 #define TIF_POLLING_NRFLAG     16
 #define TIF_USING_IWMMXT       17
 #define TIF_MEMDIE             18      /* is terminating due to OOM killer */
@@ -163,9 +164,11 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
 #define _TIF_USING_IWMMXT      (1 << TIF_USING_IWMMXT)
 #define _TIF_RESTORE_SIGMASK   (1 << TIF_RESTORE_SIGMASK)
 #define _TIF_SECCOMP           (1 << TIF_SECCOMP)
+#define _TIF_SYSCALL_RESTARTSYS        (1 << TIF_SYSCALL_RESTARTSYS)
 
 /* Checks for any syscall work in entry-common.S */
-#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT)
+#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
+                          _TIF_SYSCALL_RESTARTSYS)
 
 /*
  * Change these and you break ASM code in entry-common.S

diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 9650c143afc115fe82c2ccd5fdecad6ef02116e0..d407ebf418015f18b9a840bdb2e03e08013d6375 100644 (file)
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -24,6 +24,7 @@
 #include <linux/hw_breakpoint.h>
 #include <linux/regset.h>
 #include <linux/audit.h>
+#include <linux/unistd.h>
 
 #include <asm/pgtable.h>
 #include <asm/traps.h>
@@ -916,6 +917,8 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
                audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0,
                                    regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
 
+       if (why == 0 && test_and_clear_thread_flag(TIF_SYSCALL_RESTARTSYS))
+               scno = __NR_restart_syscall - __NR_SYSCALL_BASE;
        if (!test_thread_flag(TIF_SYSCALL_TRACE))
                return scno;
        if (!(current->ptrace & PT_PTRACED))

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 6b37d4ddf0b6cf1f13539d5d6f1060966541c4b4..75c70d1850df09efdf5856be56f677c971a8d880 100644 (file)
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -624,12 +624,10 @@ static void do_signal(struct pt_regs *regs, int syscall)
                case -ERESTARTNOHAND:
                case -ERESTARTSYS:
                case -ERESTARTNOINTR:
+               case -ERESTART_RESTARTBLOCK:
                        regs->ARM_r0 = regs->ARM_ORIG_r0;
                        regs->ARM_pc = restart_addr;
                        break;
-               case -ERESTART_RESTARTBLOCK:
-                       regs->ARM_r0 = -EINTR;
-                       break;
                }
        }
 
@@ -647,12 +645,14 @@ static void do_signal(struct pt_regs *regs, int syscall)
                 * debugger has chosen to restart at a different PC.
                 */
                if (regs->ARM_pc == restart_addr) {
-                       if (retval == -ERESTARTNOHAND
+                       if (retval == -ERESTARTNOHAND ||
+                           retval == -ERESTART_RESTARTBLOCK
                            || (retval == -ERESTARTSYS
                                && !(ka.sa.sa_flags & SA_RESTART))) {
                                regs->ARM_r0 = -EINTR;
                                regs->ARM_pc = continue_addr;
                        }
+                       clear_thread_flag(TIF_SYSCALL_RESTARTSYS);
                }
 
                if (test_thread_flag(TIF_RESTORE_SIGMASK))
@@ -679,29 +679,8 @@ static void do_signal(struct pt_regs *regs, int syscall)
                 * ignore the restart.
                 */
                if (retval == -ERESTART_RESTARTBLOCK
-                   && regs->ARM_pc == continue_addr) {
-                       if (thumb_mode(regs)) {
-                               regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
-                               regs->ARM_pc -= 2;
-                       } else {
-#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
-                               regs->ARM_r7 = __NR_restart_syscall;
-                               regs->ARM_pc -= 4;
-#else
-                               u32 __user *usp;
-
-                               regs->ARM_sp -= 4;
-                               usp = (u32 __user *)regs->ARM_sp;
-
-                               if (put_user(regs->ARM_pc, usp) == 0) {
-                                       regs->ARM_pc = KERN_RESTART_CODE;
-                               } else {
-                                       regs->ARM_sp += 4;
-                                       force_sigsegv(0, current);
-                               }
-#endif
-                       }
-               }
+                   && regs->ARM_pc == restart_addr)
+                       set_thread_flag(TIF_SYSCALL_RESTARTSYS);
        }
 
        /* If there's no signal to deliver, we just put the saved sigmask