1 files changed, 40 insertions, 6 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index fd2392a17ac1..536c5d6b340b 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -27,6 +27,7 @@
  */
 #define SWI_SYS_SIGRETURN       (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
 #define SWI_SYS_RT_SIGRETURN    (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
+#define SWI_SYS_RESTART         (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
 
 /*
  * With EABI, the syscall number has to be loaded into r7.
@@ -47,6 +48,18 @@ const unsigned long sigreturn_codes[7] = {
 };
 
 /*
+ * Either we support OABI only, or we have EABI with the OABI
+ * compat layer enabled.  In the later case we don't know if
+ * user space is EABI or not, and if not we must not clobber r7.
+ * Always using the OABI syscall solves that issue and works for
+ * all those cases.
+ */
+const unsigned long syscall_restart_code[2] = {
+        SWI_SYS_RESTART,        /* swi  __NR_restart_syscall */
+        0xe49df004,             /* ldr  pc, [sp], #4 */
+};
+
+/*
  * atomically swap in the new signal mask, and wait for a signal.
  */
 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
@@ -592,10 +605,12 @@ 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;
                 }
         }
 
@@ -611,14 +626,12 @@ 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 ||
-                            retval == -ERESTART_RESTARTBLOCK
+                        if (retval == -ERESTARTNOHAND
                             || (retval == -ERESTARTSYS
                                 && !(ka.sa.sa_flags & SA_RESTART))) {
                                 regs->ARM_r0 = -EINTR;
                                 regs->ARM_pc = continue_addr;
                         }
-                        clear_thread_flag(TIF_SYSCALL_RESTARTSYS);
                 }
 
                 handle_signal(signr, &ka, &info, regs);
@@ -632,8 +645,29 @@ static void do_signal(struct pt_regs *regs, int syscall)
                  * ignore the restart.
                  */
                 if (retval == -ERESTART_RESTARTBLOCK
-                    && regs->ARM_pc == restart_addr)
-                        set_thread_flag(TIF_SYSCALL_RESTARTSYS);
+                    && 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
+                        }
+                }
         }
 
         restore_saved_sigmask();