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