1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef __ASM_GENERIC_SHMBUF_H 3 #define __ASM_GENERIC_SHMBUF_H 4 5 #include <asm/bitsperlong.h> 6 7 /* 8 * The shmid64_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 * shmid64_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 * On big-endian systems, the lower half is in the wrong place. 19 * 20 * 21 * Pad space is left for: 22 * - 2 miscellaneous 32-bit values 23 */ 24 25 struct shmid64_ds { 26 struct ipc64_perm shm_perm; /* operation perms */ 27 size_t shm_segsz; /* size of segment (bytes) */ 28 #if __BITS_PER_LONG == 64 29 long shm_atime; /* last attach time */ 30 long shm_dtime; /* last detach time */ 31 long shm_ctime; /* last change time */ 32 #else 33 unsigned long shm_atime; /* last attach time */ 34 unsigned long shm_atime_high; 35 unsigned long shm_dtime; /* last detach time */ 36 unsigned long shm_dtime_high; 37 unsigned long shm_ctime; /* last change time */ 38 unsigned long shm_ctime_high; 39 #endif 40 __kernel_pid_t shm_cpid; /* pid of creator */ 41 __kernel_pid_t shm_lpid; /* pid of last operator */ 42 unsigned long shm_nattch; /* no. of current attaches */ 43 unsigned long __unused4; 44 unsigned long __unused5; 45 }; 46 47 struct shminfo64 { 48 unsigned long shmmax; 49 unsigned long shmmin; 50 unsigned long shmmni; 51 unsigned long shmseg; 52 unsigned long shmall; 53 unsigned long __unused1; 54 unsigned long __unused2; 55 unsigned long __unused3; 56 unsigned long __unused4; 57 }; 58 59 #endif /* __ASM_GENERIC_SHMBUF_H */ 60