path: root/arch/s390/include/uapi/asm/signal.h
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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2018-04-12 13:48:25 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-04-17 10:36:12 +0200
commitfae764912153065ea55eda47f834e0764a54df94 (patch)
treee617ff5bb25474858e2ec5a16ec6685bb4eb6307 /arch/s390/include/uapi/asm/signal.h
parent49d23a851d62c03daebae2d245dcc9b07dbfa89f (diff)
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 <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/uapi/asm/signal.h')
1 files 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 <asm-generic/signal-defs.h>
#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

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