shm.h (3793B) - Raw
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_ */