sparc: Fix debugger syscall restart interactions.

[karo-tx-linux.git] / arch / sparc64 / kernel / signal.c

diff --git a/arch/sparc64/kernel/signal.c b/arch/sparc64/kernel/signal.c
index 1c47009eb5ec09068e7417d4c158c97c841c230d..2378482c2aaba0299c1d61c0d44dc613c77aaa8b 100644 (file)
--- a/arch/sparc64/kernel/signal.c
+++ b/arch/sparc64/kernel/signal.c
@@ -8,7 +8,7 @@
  *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
  */
 
-#ifdef CONFIG_SPARC32_COMPAT
+#ifdef CONFIG_COMPAT
 #include <linux/compat.h>      /* for compat_old_sigset_t */
 #endif
 #include <linux/sched.h>
@@ -236,9 +236,6 @@ struct rt_signal_frame {
        __siginfo_fpu_t         fpu_state;
 };
 
-/* Align macros */
-#define RT_ALIGNEDSZ  (((sizeof(struct rt_signal_frame) + 7) & (~7)))
-
 static long _sigpause_common(old_sigset_t set)
 {
        set &= _BLOCKABLE;
@@ -335,6 +332,9 @@ void do_rt_sigreturn(struct pt_regs *regs)
        regs->tpc = tpc;
        regs->tnpc = tnpc;
 
+       /* Prevent syscall restart.  */
+       pt_regs_clear_syscall(regs);
+
        sigdelsetmask(&set, ~_BLOCKABLE);
        spin_lock_irq(&current->sighand->siglock);
        current->blocked = set;
@@ -376,16 +376,29 @@ save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
 
 static inline void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, unsigned long framesize)
 {
-       unsigned long sp;
+       unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;
 
-       sp = regs->u_regs[UREG_FP] + STACK_BIAS;
+       /*
+        * If we are on the alternate signal stack and would overflow it, don't.
+        * Return an always-bogus address instead so we will die with SIGSEGV.
+        */
+       if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
+               return (void __user *) -1L;
 
        /* This is the X/Open sanctioned signal stack switching.  */
        if (ka->sa.sa_flags & SA_ONSTACK) {
-               if (!on_sig_stack(sp) &&
-                   !((current->sas_ss_sp + current->sas_ss_size) & 7))
+               if (sas_ss_flags(sp) == 0)
                        sp = current->sas_ss_sp + current->sas_ss_size;
        }
+
+       /* Always align the stack frame.  This handles two cases.  First,
+        * sigaltstack need not be mindful of platform specific stack
+        * alignment.  Second, if we took this signal because the stack
+        * is not aligned properly, we'd like to take the signal cleanly
+        * and report that.
+        */
+       sp &= ~7UL;
+
        return (void __user *)(sp - framesize);
 }
 
@@ -400,7 +413,7 @@ setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
        synchronize_user_stack();
        save_and_clear_fpu();
        
-       sigframe_size = RT_ALIGNEDSZ;
+       sigframe_size = sizeof(struct rt_signal_frame);
        if (!(current_thread_info()->fpsaved[0] & FPRS_FEF))
                sigframe_size -= sizeof(__siginfo_fpu_t);
 
@@ -486,7 +499,7 @@ static inline void handle_signal(unsigned long signr, struct k_sigaction *ka,
 }
 
 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
-                                    struct sigaction *sa)
+                                  struct sigaction *sa)
 {
        switch (regs->u_regs[UREG_I0]) {
        case ERESTART_RESTARTBLOCK:
@@ -510,35 +523,46 @@ static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  */
-static void do_signal(struct pt_regs *regs, unsigned long orig_i0, int restart_syscall)
+static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
 {
-       siginfo_t info;
-       struct signal_deliver_cookie cookie;
        struct k_sigaction ka;
-       int signr;
+       int restart_syscall;
        sigset_t *oldset;
+       siginfo_t info;
+       int signr;
        
-       cookie.restart_syscall = restart_syscall;
-       cookie.orig_i0 = orig_i0;
+       if (pt_regs_is_syscall(regs) &&
+           (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
+               restart_syscall = 1;
+       } else
+               restart_syscall = 0;
 
        if (test_thread_flag(TIF_RESTORE_SIGMASK))
                oldset = &current->saved_sigmask;
        else
                oldset = &current->blocked;
 
-#ifdef CONFIG_SPARC32_COMPAT
+#ifdef CONFIG_COMPAT
        if (test_thread_flag(TIF_32BIT)) {
                extern void do_signal32(sigset_t *, struct pt_regs *,
-                                       unsigned long, int);
-               do_signal32(oldset, regs, orig_i0,
-                           cookie.restart_syscall);
+                                       int restart_syscall,
+                                       unsigned long orig_i0);
+               do_signal32(oldset, regs, restart_syscall, orig_i0);
                return;
        }
 #endif 
 
-       signr = get_signal_to_deliver(&info, &ka, regs, &cookie);
+       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;
+
        if (signr > 0) {
-               if (cookie.restart_syscall)
+               if (restart_syscall)
                        syscall_restart(orig_i0, regs, &ka.sa);
                handle_signal(signr, &ka, &info, oldset, regs);
 
@@ -551,16 +575,16 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0, int restart_s
                        clear_thread_flag(TIF_RESTORE_SIGMASK);
                return;
        }
-       if (cookie.restart_syscall &&
+       if (restart_syscall &&
            (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
             regs->u_regs[UREG_I0] == ERESTARTSYS ||
             regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
                /* replay the system call when we are done */
-               regs->u_regs[UREG_I0] = cookie.orig_i0;
+               regs->u_regs[UREG_I0] = orig_i0;
                regs->tpc -= 4;
                regs->tnpc -= 4;
        }
-       if (cookie.restart_syscall &&
+       if (restart_syscall &&
            regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
                regs->u_regs[UREG_G1] = __NR_restart_syscall;
                regs->tpc -= 4;
@@ -576,32 +600,8 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0, int restart_s
        }
 }
 
-void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, int restart_syscall,
-                     unsigned long thread_info_flags)
+void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
 {
        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
-               do_signal(regs, orig_i0, restart_syscall);
-}
-
-void ptrace_signal_deliver(struct pt_regs *regs, void *cookie)
-{
-       struct signal_deliver_cookie *cp = cookie;
-
-       if (cp->restart_syscall &&
-           (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
-            regs->u_regs[UREG_I0] == ERESTARTSYS ||
-            regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
-               /* replay the system call when we are done */
-               regs->u_regs[UREG_I0] = cp->orig_i0;
-               regs->tpc -= 4;
-               regs->tnpc -= 4;
-               cp->restart_syscall = 0;
-       }
-       if (cp->restart_syscall &&
-           regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
-               regs->u_regs[UREG_G1] = __NR_restart_syscall;
-               regs->tpc -= 4;
-               regs->tnpc -= 4;
-               cp->restart_syscall = 0;
-       }
+               do_signal(regs, orig_i0);
 }