lkml.org 
[lkml]   [2015]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/3] CRISv32: handle multiple signals
Date
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 0a267fa6a15d41c
("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>
---
arch/cris/arch-v32/kernel/entry.S | 35 +++--------------------------------
arch/cris/kernel/ptrace.c | 23 +++++++++++++++++++++++
2 files changed, 26 insertions(+), 32 deletions(-)

diff --git a/arch/cris/arch-v32/kernel/entry.S b/arch/cris/arch-v32/kernel/entry.S
index 1ea29b7..026a0b2 100644
--- a/arch/cris/arch-v32/kernel/entry.S
+++ b/arch/cris/arch-v32/kernel/entry.S
@@ -281,43 +281,14 @@ _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
diff --git a/arch/cris/kernel/ptrace.c b/arch/cris/kernel/ptrace.c
index 58d44ee..fd3427e 100644
--- a/arch/cris/kernel/ptrace.c
+++ b/arch/cris/kernel/ptrace.c
@@ -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);
+}
--
2.1.4


\
 
 \ /
  Last update: 2015-02-08 22:01    [W:0.051 / U:6.972 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site