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