Commit 9e4930db authored by Al Viro's avatar Al Viro Committed by Geert Uytterhoeven
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent e68847fe

arch/m68k/kernel/entry.S

+1 −5
Original line number Diff line number Diff line
@@ -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

arch/m68k/kernel/signal.c

+7 −4
Original line number Diff line number Diff line
@@ -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;

}

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