xref: /OK3568_Linux_fs/kernel/include/uapi/asm-generic/sembuf.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2*4882a593Smuzhiyun #ifndef __ASM_GENERIC_SEMBUF_H
3*4882a593Smuzhiyun #define __ASM_GENERIC_SEMBUF_H
4*4882a593Smuzhiyun 
5*4882a593Smuzhiyun #include <asm/bitsperlong.h>
6*4882a593Smuzhiyun #include <asm/ipcbuf.h>
7*4882a593Smuzhiyun 
8*4882a593Smuzhiyun /*
9*4882a593Smuzhiyun  * The semid64_ds structure for x86 architecture.
10*4882a593Smuzhiyun  * Note extra padding because this structure is passed back and forth
11*4882a593Smuzhiyun  * between kernel and user space.
12*4882a593Smuzhiyun  *
13*4882a593Smuzhiyun  * semid64_ds was originally meant to be architecture specific, but
14*4882a593Smuzhiyun  * everyone just ended up making identical copies without specific
15*4882a593Smuzhiyun  * optimizations, so we may just as well all use the same one.
16*4882a593Smuzhiyun  *
17*4882a593Smuzhiyun  * 64 bit architectures use a 64-bit long time field here, while
18*4882a593Smuzhiyun  * 32 bit architectures have a pair of unsigned long values.
19*4882a593Smuzhiyun  *
20*4882a593Smuzhiyun  * On big-endian systems, the padding is in the wrong place for
21*4882a593Smuzhiyun  * historic reasons, so user space has to reconstruct a time_t
22*4882a593Smuzhiyun  * value using
23*4882a593Smuzhiyun  *
24*4882a593Smuzhiyun  * user_semid_ds.sem_otime = kernel_semid64_ds.sem_otime +
25*4882a593Smuzhiyun  *		((long long)kernel_semid64_ds.sem_otime_high << 32)
26*4882a593Smuzhiyun  *
27*4882a593Smuzhiyun  * Pad space is left for 2 miscellaneous 32-bit values
28*4882a593Smuzhiyun  */
29*4882a593Smuzhiyun struct semid64_ds {
30*4882a593Smuzhiyun 	struct ipc64_perm sem_perm;	/* permissions .. see ipc.h */
31*4882a593Smuzhiyun #if __BITS_PER_LONG == 64
32*4882a593Smuzhiyun 	long		sem_otime;	/* last semop time */
33*4882a593Smuzhiyun 	long		sem_ctime;	/* last change time */
34*4882a593Smuzhiyun #else
35*4882a593Smuzhiyun 	unsigned long	sem_otime;	/* last semop time */
36*4882a593Smuzhiyun 	unsigned long	sem_otime_high;
37*4882a593Smuzhiyun 	unsigned long	sem_ctime;	/* last change time */
38*4882a593Smuzhiyun 	unsigned long	sem_ctime_high;
39*4882a593Smuzhiyun #endif
40*4882a593Smuzhiyun 	unsigned long	sem_nsems;	/* no. of semaphores in array */
41*4882a593Smuzhiyun 	unsigned long	__unused3;
42*4882a593Smuzhiyun 	unsigned long	__unused4;
43*4882a593Smuzhiyun };
44*4882a593Smuzhiyun 
45*4882a593Smuzhiyun #endif /* __ASM_GENERIC_SEMBUF_H */
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