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 */
28 struct shmid_ds {
29 struct ipc_perm shm_perm; /* operation perms */
30 int shm_segsz; /* size of segment (bytes) */
31 __kernel_time_t shm_atime; /* last attach time */
32 __kernel_time_t shm_dtime; /* last detach time */
33 __kernel_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 */
93 struct shminfo {
94 int shmmax;
95 int shmmin;
96 int shmmni;
97 int shmseg;
98 int shmall;
99 };
100
101 struct 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_ */