diff options
Diffstat (limited to 'arch/sparc/kernel/signal_64.c')
| -rw-r--r-- | arch/sparc/kernel/signal_64.c | 42 |
1 files changed, 28 insertions, 14 deletions
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c index 47509df3b893..d58260bff2df 100644 --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -535,11 +535,27 @@ 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. + * + * Although it should be the case that most of the global + * registers are volatile across a system call, glibc already + * depends upon that fact that we preserve them. So we can't + * just use any global register to save away the orig_i0 value. + * + * In particular %g2, %g3, %g4, and %g5 are all assumed to be + * preserved across a system call trap by various pieces of + * code in glibc. + * + * %g7 is used as the "thread register". %g6 is not used in + * any fixed manner. %g6 is used as a scratch register and + * a compiler temporary, but it's value is never used across + * a system call. Therefore %g6 is usable for orig_i0 storage. + */ if (pt_regs_is_syscall(regs) && - (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) { - restart_syscall = 1; - } else - restart_syscall = 0; + (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) + regs->u_regs[UREG_G6] = orig_i0; if (current_thread_info()->status & TS_RESTORE_SIGMASK) oldset = ¤t->saved_sigmask; @@ -548,22 +564,20 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0) #ifdef CONFIG_COMPAT if (test_thread_flag(TIF_32BIT)) { - extern void do_signal32(sigset_t *, struct pt_regs *, - int restart_syscall, - unsigned long orig_i0); - do_signal32(oldset, regs, restart_syscall, orig_i0); + extern void do_signal32(sigset_t *, struct pt_regs *); + do_signal32(oldset, regs); return; } #endif signr = get_signal_to_deliver(&info, &ka, regs, NULL); - /* If the debugger messes with the program counter, it clears - * 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->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) { + restart_syscall = 1; + orig_i0 = regs->u_regs[UREG_G6]; + } if (signr > 0) { if (restart_syscall) |