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 __kernel_time_t here, while 17 * 32 bit architectures have a pair of unsigned long values. 18 * so they do not need the first two padding words. 19 * 20 * On big-endian systems, the padding is in the wrong place for 21 * historic reasons, so user space has to reconstruct a time_t 22 * value using 23 * 24 * user_semid_ds.sem_otime = kernel_semid64_ds.sem_otime + 25 * ((long long)kernel_semid64_ds.sem_otime_high << 32) 26 * 27 * Pad space is left for 2 miscellaneous 32-bit values 28 */ 29 struct semid64_ds { 30 struct ipc64_perm sem_perm; /* permissions .. see ipc.h */ 31 #if __BITS_PER_LONG == 64 32 __kernel_time_t sem_otime; /* last semop time */ 33 __kernel_time_t sem_ctime; /* last change time */ 34 #else 35 unsigned long sem_otime; /* last semop time */ 36 unsigned long sem_otime_high; 37 unsigned long sem_ctime; /* last change time */ 38 unsigned long sem_ctime_high; 39 #endif 40 unsigned long sem_nsems; /* no. of semaphores in array */ 41 unsigned long __unused3; 42 unsigned long __unused4; 43 }; 44 45 #endif /* __ASM_GENERIC_SEMBUF_H */ 46
