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| author | Jonas Bonn <jonas@southpole.se> | 2013-09-23 12:04:20 +0200 |
|---|---|---|
| committer | Stafford Horne <shorne@gmail.com> | 2016-12-12 23:09:16 +0900 |
| commit | c79902190f7e61fcae7c3f4b613c75062f385678 (patch) | |
| tree | 984b7b693fc73b5ff99a56de14a9d215603af0b8 /arch/openrisc | |
| parent | f47706099bdb8c0e6300d6f5ba8e542861aa3ac5 (diff) | |
| download | lwn-c79902190f7e61fcae7c3f4b613c75062f385678.tar.gz lwn-c79902190f7e61fcae7c3f4b613c75062f385678.zip | |
openrisc: restore all regs on rt_sigreturn
Fix signal handling for when signals are handled as the result of timers
or exceptions, previous code assumed syscalls. This was noticeable with X
crashing where it uses SIGALRM.
This patch restores all regs before returning to userspace via
_resume_userspace instead of via syscall return path.
The rt_sigreturn syscall is more like a context switch than a function
call; it entails a return from one context (the signal handler) to another
(the process in question). For a context switch like this there are
effectively no call-saved regs that remain constant across the transition.
Reported-by: Sebastian Macke <sebastian@macke.de>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Tested-by: Guenter Roeck <linux@roeck-us.net>
[shorne@gmail.com: Updated comment better reflect change and issue]
Signed-off-by: Stafford Horne <shorne@gmail.com>
Diffstat (limited to 'arch/openrisc')
| -rw-r--r-- | arch/openrisc/kernel/entry.S | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/openrisc/kernel/entry.S b/arch/openrisc/kernel/entry.S index fec8bf97d806..572d223dbd26 100644 --- a/arch/openrisc/kernel/entry.S +++ b/arch/openrisc/kernel/entry.S @@ -1101,8 +1101,16 @@ ENTRY(__sys_fork) l.addi r3,r1,0 ENTRY(sys_rt_sigreturn) - l.j _sys_rt_sigreturn + l.jal _sys_rt_sigreturn l.addi r3,r1,0 + l.sfne r30,r0 + l.bnf _no_syscall_trace + l.nop + l.jal do_syscall_trace_leave + l.addi r3,r1,0 +_no_syscall_trace: + l.j _resume_userspace + l.nop /* This is a catch-all syscall for atomic instructions for the OpenRISC 1000. * The functions takes a variable number of parameters depending on which |