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authorJonas Bonn <jonas@southpole.se>2013-09-23 12:04:20 +0200
committerStafford Horne <shorne@gmail.com>2016-12-12 23:09:16 +0900
commitc79902190f7e61fcae7c3f4b613c75062f385678 (patch)
tree984b7b693fc73b5ff99a56de14a9d215603af0b8
parentf47706099bdb8c0e6300d6f5ba8e542861aa3ac5 (diff)
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>
-rw-r--r--arch/openrisc/kernel/entry.S10
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