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>

1 files changed, 1 insertions, 5 deletions

diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 3a15a03297a..4e49f577769 100644
--- 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