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Groups > linux.kernel > #1521644
| From | Stafford Horne <shorne@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v2 2/9] openrisc: restore all regs on rt_sigreturn |
| Date | 2016-11-14 14:40 +0100 |
| Message-ID | <sDpEm-7Av-27@gated-at.bofh.it> (permalink) |
| References | <sDpEl-7Av-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Jonas Bonn <jonas@southpole.se> 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> --- 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 fec8bf9..572d223 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 -- 2.7.4
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[PATCH v2 2/9] openrisc: restore all regs on rt_sigreturn Stafford Horne <shorne@gmail.com> - 2016-11-14 14:40 +0100
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