From fae764912153065ea55eda47f834e0764a54df94 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Thu, 12 Apr 2018 13:48:25 +0200 Subject: [PATCH] s390/signal: cleanup uapi struct sigaction The struct sigaction for user space in arch/s390/include/uapi/asm/signal.h is ill defined. The kernel uses two structures 'struct sigaction' and 'struct old_sigaction', the correlation in the kernel for both 31 and 64 bit is as follows sys_sigaction -> struct old_sigaction sys_rt_sigaction -> struct sigaction The correlation of the (single) uapi definition for 'struct sigaction' under '#ifndef __KERNEL__': 31-bit: sys_sigaction -> uapi struct sigaction 31-bit: sys_rt_sigaction -> no structure available 64-bit: sys_sigaction -> no structure available 64-bit: sys_rt_sigaction -> uapi struct sigaction This is quite confusing. To make it a bit less confusing make the uapi definition of 'struct sigaction' usable for sys_rt_sigaction for both 31-bit and 64-bit. Signed-off-by: Martin Schwidefsky --- arch/s390/include/uapi/asm/signal.h | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/uapi/asm/signal.h b/arch/s390/include/uapi/asm/signal.h index c57f9d28d894..9a14a611ed82 100644 --- a/arch/s390/include/uapi/asm/signal.h +++ b/arch/s390/include/uapi/asm/signal.h @@ -97,22 +97,31 @@ typedef unsigned long sigset_t; #include #ifndef __KERNEL__ -/* Here we must cater to libcs that poke about in kernel headers. */ +/* + * There are two system calls in regard to sigaction, sys_rt_sigaction + * and sys_sigaction. Internally the kernel uses the struct old_sigaction + * for the older sys_sigaction system call, and the kernel version of the + * struct sigaction for the newer sys_rt_sigaction. + * + * The uapi definition for struct sigaction has made a strange distinction + * between 31-bit and 64-bit in the past. For 64-bit the uapi structure + * looks like the kernel struct sigaction, but for 31-bit it used to + * look like the kernel struct old_sigaction. That practically made the + * structure unusable for either system call. To get around this problem + * the glibc always had its own definitions for the sigaction structures. + * + * The current struct sigaction uapi definition below is suitable for the + * sys_rt_sigaction system call only. + */ struct sigaction { union { __sighandler_t _sa_handler; void (*_sa_sigaction)(int, struct siginfo *, void *); } _u; -#ifndef __s390x__ /* lovely */ - sigset_t sa_mask; - unsigned long sa_flags; - void (*sa_restorer)(void); -#else /* __s390x__ */ unsigned long sa_flags; void (*sa_restorer)(void); sigset_t sa_mask; -#endif /* __s390x__ */ }; #define sa_handler _u._sa_handler