1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _UAPI_LINUX_SHM_H_
3#define _UAPI_LINUX_SHM_H_
4
5#include <linux/ipc.h>
6#include <linux/errno.h>
7#include <asm-generic/hugetlb_encode.h>
8#ifndef __KERNEL__
9#include <unistd.h>
10#endif
11
12/*
13 * SHMMNI, SHMMAX and SHMALL are default upper limits which can be
14 * modified by sysctl. The SHMMAX and SHMALL values have been chosen to
15 * be as large possible without facilitating scenarios where userspace
16 * causes overflows when adjusting the limits via operations of the form
17 * "retrieve current limit; add X; update limit". It is therefore not
18 * advised to make SHMMAX and SHMALL any larger. These limits are
19 * suitable for both 32 and 64-bit systems.
20 */
21#define SHMMIN 1 /* min shared seg size (bytes) */
22#define SHMMNI 4096 /* max num of segs system wide */
23#define SHMMAX (ULONG_MAX - (1UL << 24)) /* max shared seg size (bytes) */
24#define SHMALL (ULONG_MAX - (1UL << 24)) /* max shm system wide (pages) */
25#define SHMSEG SHMMNI /* max shared segs per process */
26
27/* Obsolete, used only for backwards compatibility and libc5 compiles */
28struct shmid_ds {
29 struct ipc_perm shm_perm; /* operation perms */
30 int shm_segsz; /* size of segment (bytes) */
31 __kernel_old_time_t shm_atime; /* last attach time */
32 __kernel_old_time_t shm_dtime; /* last detach time */
33 __kernel_old_time_t shm_ctime; /* last change time */
34 __kernel_ipc_pid_t shm_cpid; /* pid of creator */
35 __kernel_ipc_pid_t shm_lpid; /* pid of last operator */
36 unsigned short shm_nattch; /* no. of current attaches */
37 unsigned short shm_unused; /* compatibility */
38 void *shm_unused2; /* ditto - used by DIPC */
39 void *shm_unused3; /* unused */
40};
41
42/* Include the definition of shmid64_ds and shminfo64 */
43#include <asm/shmbuf.h>
44
45/*
46 * shmget() shmflg values.
47 */
48/* The bottom nine bits are the same as open(2) mode flags */
49#define SHM_R 0400 /* or S_IRUGO from <linux/stat.h> */
50#define SHM_W 0200 /* or S_IWUGO from <linux/stat.h> */
51/* Bits 9 & 10 are IPC_CREAT and IPC_EXCL */
52#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
53#define SHM_NORESERVE 010000 /* don't check for reservations */
54
55/*
56 * Huge page size encoding when SHM_HUGETLB is specified, and a huge page
57 * size other than the default is desired. See hugetlb_encode.h
58 */
59#define SHM_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
60#define SHM_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
61
62#define SHM_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB
63#define SHM_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
64#define SHM_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
65#define SHM_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
66#define SHM_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
67#define SHM_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB
68#define SHM_HUGE_32MB HUGETLB_FLAG_ENCODE_32MB
69#define SHM_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
70#define SHM_HUGE_512MB HUGETLB_FLAG_ENCODE_512MB
71#define SHM_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
72#define SHM_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
73#define SHM_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB
74
75/*
76 * shmat() shmflg values
77 */
78#define SHM_RDONLY 010000 /* read-only access */
79#define SHM_RND 020000 /* round attach address to SHMLBA boundary */
80#define SHM_REMAP 040000 /* take-over region on attach */
81#define SHM_EXEC 0100000 /* execution access */
82
83/* super user shmctl commands */
84#define SHM_LOCK 11
85#define SHM_UNLOCK 12
86
87/* ipcs ctl commands */
88#define SHM_STAT 13
89#define SHM_INFO 14
90#define SHM_STAT_ANY 15
91
92/* Obsolete, used only for backwards compatibility */
93struct shminfo {
94 int shmmax;
95 int shmmin;
96 int shmmni;
97 int shmseg;
98 int shmall;
99};
100
101struct shm_info {
102 int used_ids;
103 __kernel_ulong_t shm_tot; /* total allocated shm */
104 __kernel_ulong_t shm_rss; /* total resident shm */
105 __kernel_ulong_t shm_swp; /* total swapped shm */
106 __kernel_ulong_t swap_attempts;
107 __kernel_ulong_t swap_successes;
108};
109
110
111#endif /* _UAPI_LINUX_SHM_H_ */
112