From c79902190f7e61fcae7c3f4b613c75062f385678 Mon Sep 17 00:00:00 2001 From: Jonas Bonn Date: Mon, 23 Sep 2013 12:04:20 +0200 Subject: [PATCH] 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 Signed-off-by: Jonas Bonn Tested-by: Guenter Roeck [shorne@gmail.com: Updated comment better reflect change and issue] Signed-off-by: Stafford Horne --- arch/openrisc/kernel/entry.S | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) 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 -- 2.20.1