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Diffstat (limited to 'include/uapi/asm-generic/sembuf.h')
| -rw-r--r-- | include/uapi/asm-generic/sembuf.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/sembuf.h b/include/uapi/asm-generic/sembuf.h new file mode 100644 index 000000000..0bae010f1 --- /dev/null +++ b/include/uapi/asm-generic/sembuf.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __ASM_GENERIC_SEMBUF_H +#define __ASM_GENERIC_SEMBUF_H + +#include <asm/bitsperlong.h> + +/* + * The semid64_ds structure for x86 architecture. + * Note extra padding because this structure is passed back and forth + * between kernel and user space. + * + * semid64_ds was originally meant to be architecture specific, but + * everyone just ended up making identical copies without specific + * optimizations, so we may just as well all use the same one. + * + * 64 bit architectures use a 64-bit __kernel_time_t here, while + * 32 bit architectures have a pair of unsigned long values. + * so they do not need the first two padding words. + * + * On big-endian systems, the padding is in the wrong place for + * historic reasons, so user space has to reconstruct a time_t + * value using + * + * user_semid_ds.sem_otime = kernel_semid64_ds.sem_otime + + * ((long long)kernel_semid64_ds.sem_otime_high << 32) + * + * Pad space is left for 2 miscellaneous 32-bit values + */ +struct semid64_ds { + struct ipc64_perm sem_perm; /* permissions .. see ipc.h */ +#if __BITS_PER_LONG == 64 + __kernel_time_t sem_otime; /* last semop time */ + __kernel_time_t sem_ctime; /* last change time */ +#else + unsigned long sem_otime; /* last semop time */ + unsigned long sem_otime_high; + unsigned long sem_ctime; /* last change time */ + unsigned long sem_ctime_high; +#endif + unsigned long sem_nsems; /* no. of semaphores in array */ + unsigned long __unused3; + unsigned long __unused4; +}; + +#endif /* __ASM_GENERIC_SEMBUF_H */ |