m68k: Simplify the singlestepping handling in signals

Instead of checking the return value of do_signal() we can just do
the work (raise SIGTRAP and clear SR.T1) directly in handle_signal(),
when setting the sigframe up.  Simplifies the assembler glue and is
closer to the way we do it on other targets.

Note that do_delayed_trace does *not* disappear; it's still needed
to deal with single-stepping through syscall, since 68040 doesn't
raise the trace exception at all if the trap exception is pending.
We hit it after returning from sys_...() if TIF_DELAYED_TRACE is
set; all that has changed is that we don't reuse it for "single-step
into the handler" codepath.

As the result, do_signal() doesn't need to return anything anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 3a15a03297a75c3f2ddb97d473b614d1a7ab8969..4e49f57776967cc2eb545810176fae3a25cc64b1 100644 (file)
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -178,11 +178,7 @@ do_signal_return:
        addql   #4,%sp
        RESTORE_SWITCH_STACK
        addql   #4,%sp
-       tstl    %d0
-       jeq     resume_userspace
-       | when single stepping into handler stop at the first insn
-       btst    #6,%curptr@(TASK_INFO+TINFO_FLAGS+2)
-       jeq     resume_userspace
+       jbra    resume_userspace
 
 do_delayed_trace:
        bclr    #7,%sp@(PT_OFF_SR)      | clear trace bit in SR

diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index fa8200d03de27fea5484f60bf0ea2c39e802f2a3..a18b251fe593c047b237bb4225f7ff1a0e8033fb 100644 (file)
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -978,6 +978,11 @@ handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
        if (!(ka->sa.sa_flags & SA_NODEFER))
                sigaddset(&current->blocked,sig);
        recalc_sigpending();
+
+       if (test_thread_flag(TIF_DELAYED_TRACE)) {
+               regs->sr &= ~0x8000;
+               send_sig(SIGTRAP, current, 1);
+       }
 }
 
 /*
@@ -985,7 +990,7 @@ handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  */
-asmlinkage int do_signal(struct pt_regs *regs)
+asmlinkage void do_signal(struct pt_regs *regs)
 {
        siginfo_t info;
        struct k_sigaction ka;
@@ -1004,7 +1009,7 @@ asmlinkage int do_signal(struct pt_regs *regs)
                /* Whee!  Actually deliver the signal.  */
                handle_signal(signr, &ka, &info, oldset, regs);
                clear_thread_flag(TIF_RESTORE_SIGMASK);
-               return 1;
+               return;
        }
 
        /* Did we come from a system call? */
@@ -1017,6 +1022,4 @@ asmlinkage int do_signal(struct pt_regs *regs)
                clear_thread_flag(TIF_RESTORE_SIGMASK);
                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
        }
-
-       return 0;
 }