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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>
This commit is contained in:
Al Viro 2010-10-02 22:57:30 -04:00 committed by Geert Uytterhoeven
parent e68847fee7
commit 9e4930dbf1
2 changed files with 8 additions and 9 deletions
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6
arch/m68k/kernel/entry.S
View File

@ -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

11
arch/m68k/kernel/signal.c
View File

@ -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;
}