linux/include/uapi/asm-generic/sembuf.h
Viresh Kumar 2a45a08a5b asm-generic/sembuf: Update architecture related information in comment
The structure came originally from x86_32 but is used by most of the
architectures now. Update the comment which says it is for x86 only.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/64efe033394b6f0dfef043a63fd8897a81ba6d16.1589970173.git.viresh.kumar@linaro.org'
2020-10-26 16:48:22 +01:00

46 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef __ASM_GENERIC_SEMBUF_H
#define __ASM_GENERIC_SEMBUF_H
#include <asm/bitsperlong.h>
#include <asm/ipcbuf.h>
/*
* The semid64_ds structure for most architectures (though it came from x86_32
* originally). 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 long time field here, while
* 32 bit architectures have a pair of unsigned long values.
*
* 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
long sem_otime; /* last semop time */
long 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 */