sparc: Fix handling of orig_i0 wrt. debugging when restarting syscalls.

[deliverable/linux.git] / arch / sparc / kernel / signal_32.c

diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 8ce247ac04cc0d905abd7d7e1d5de20073ce654a..7dfaff64cd6b48d30a4c34072b5bedde7d9508d9 100644 (file)
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -519,10 +519,16 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
        siginfo_t info;
        int signr;
 
+       /* It's a lot of work and synchronization to add a new ptrace
+        * register for GDB to save and restore in order to get
+        * orig_i0 correct for syscall restarts when debugging.
+        *
+        * However, we luckily can use the fact that several registers
+        * are volatile across system calls.  One such register is
+        * %g2, so use that as a place to save away orig_i0.
+        */
        if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
-               restart_syscall = 1;
-       else
-               restart_syscall = 0;
+               regs->u_regs[UREG_G2] = orig_i0;
 
        if (test_thread_flag(TIF_RESTORE_SIGMASK))
                oldset = &current->saved_sigmask;
@@ -535,8 +541,12 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         * the software "in syscall" bit, directing us to not perform
         * a syscall restart.
         */
-       if (restart_syscall && !pt_regs_is_syscall(regs))
-               restart_syscall = 0;
+       restart_syscall = 0;
+       if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) {
+               restart_syscall = 1;
+               orig_i0 = regs->u_regs[UREG_G2];
+       }
+
 
        if (signr > 0) {
                if (restart_syscall)