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CRISv32: handle multiple signals 

Al Viro noted that CRIS fails to handle multiple signals.

This fixes the problem for CRISv32 by making it use a C work_pending
handling loop similar to the ARM implementation in 0a267fa6a1
("ARM: 7472/1: pull all work_pending logics into C function").

This also happens to fixes the warnings which currently trigger on
CRISv32 due to do_signal() being called with interrupts disabled.

Test case (should die of the SIGSEGV which gets raised when setting up
the stack for SIGALRM, but instead reaches and executes the _exit(1)):

  #include <unistd.h>
  #include <signal.h>
  #include <sys/time.h>
  #include <err.h>

  static void handler(int sig) { }

  int main(int argc, char *argv[])
  {
  	int ret;
  	struct itimerval t1 = { .it_value = {1} };
  	stack_t ss = {
  		.ss_sp = NULL,
  		.ss_size = SIGSTKSZ,
  	};
  	struct sigaction action = {
  		.sa_handler = handler,
  		.sa_flags = SA_ONSTACK,
  	};

  	ret = sigaltstack(&ss, NULL);
  	if (ret < 0)
  		err(1, "sigaltstack");

  	sigaction(SIGALRM, &action, NULL);
   	setitimer(ITIMER_REAL, &t1, NULL);

  	pause();

  	_exit(1);

  	return 0;
  }

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Link: http://lkml.kernel.org/r/20121208074429.GC4939@ZenIV.linux.org.uk
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jesper Nilsson <jespern@axis.com>
This commit is contained in:
Rabin Vincent 2015-02-08 18:19:17 +01:00 committed by Jesper Nilsson
parent 0f72e5c0df
commit 9a7449d3e9
2 changed files with 26 additions and 32 deletions
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35
arch/cris/arch-v32/kernel/entry.S
View File

@ -280,44 +280,15 @@ _syscall_exit_work:
.type _work_pending,@function
_work_pending:
addoq +TI_flags, $r0, $acr
move.d [$acr], $r10
btstq TIF_NEED_RESCHED, $r10 ; Need resched?
bpl _work_notifysig ; No, must be signal/notify.
nop
.size _work_pending, . - _work_pending
.type _work_resched,@function
_work_resched:
move.d $r9, $r1 ; Preserve R9.
jsr schedule
nop
move.d $r1, $r9
di
addoq +TI_flags, $r0, $acr
move.d [$acr], $r1
and.d _TIF_WORK_MASK, $r1 ; Ignore sycall trace counter.
beq _Rexit
nop
btstq TIF_NEED_RESCHED, $r1
bmi _work_resched ; current->work.need_resched.
nop
.size _work_resched, . - _work_resched
.type _work_notifysig,@function
_work_notifysig:
;; Deal with pending signals and notify-resume requests.
addoq +TI_flags, $r0, $acr
move.d [$acr], $r12 ; The thread_info_flags parameter.
move.d $sp, $r11 ; The regs param.
jsr do_notify_resume
move.d $r9, $r10 ; do_notify_resume syscall/irq param.
jsr do_work_pending
move.d $r9, $r10 ; The syscall/irq param.
ba _Rexit
nop
.size _work_notifysig, . - _work_notifysig
.size _work_pending, . - _work_pending
;; We get here as a sidetrack when we've entered a syscall with the
;; trace-bit set. We need to call do_syscall_trace and then continue

23
arch/cris/kernel/ptrace.c
View File

@ -42,3 +42,26 @@ void do_notify_resume(int canrestart, struct pt_regs *regs,
tracehook_notify_resume(regs);
}
}
void do_work_pending(int syscall, struct pt_regs *regs,
unsigned int thread_flags)
{
do {
if (likely(thread_flags & _TIF_NEED_RESCHED)) {
schedule();
} else {
if (unlikely(!user_mode(regs)))
return;
local_irq_enable();
if (thread_flags & _TIF_SIGPENDING) {
do_signal(syscall, regs);
syscall = 0;
} else {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
local_irq_disable();
thread_flags = current_thread_info()->flags;
} while (thread_flags & _TIF_WORK_MASK);
}