/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ #ifndef _LINUX_SHM_H_ #define _LINUX_SHM_H_ #include <linux/ipc.h> #include <linux/errno.h> #include <asm-generic/hugetlb_encode.h> #include <unistd.h> /* * SHMMNI, SHMMAX and SHMALL are default upper limits which can be * modified by sysctl. The SHMMAX and SHMALL values have been chosen to * be as large possible without facilitating scenarios where userspace * causes overflows when adjusting the limits via operations of the form * "retrieve current limit; add X; update limit". It is therefore not * advised to make SHMMAX and SHMALL any larger. These limits are * suitable for both 32 and 64-bit systems. */ #define SHMMIN 1 /* min shared seg size (bytes) */ #define SHMMNI 4096 /* max num of segs system wide */ #define SHMMAX (ULONG_MAX - (1UL << 24)) /* max shared seg size (bytes) */ #define SHMALL (ULONG_MAX - (1UL << 24)) /* max shm system wide (pages) */ #define SHMSEG SHMMNI /* max shared segs per process */ /* Obsolete, used only for backwards compatibility and libc5 compiles */ struct shmid_ds { struct ipc_perm shm_perm; /* operation perms */ int shm_segsz; /* size of segment (bytes) */ __kernel_old_time_t shm_atime; /* last attach time */ __kernel_old_time_t shm_dtime; /* last detach time */ __kernel_old_time_t shm_ctime; /* last change time */ __kernel_ipc_pid_t shm_cpid; /* pid of creator */ __kernel_ipc_pid_t shm_lpid; /* pid of last operator */ unsigned short shm_nattch; /* no. of current attaches */ unsigned short shm_unused; /* compatibility */ void *shm_unused2; /* ditto - used by DIPC */ void *shm_unused3; /* unused */ }; /* Include the definition of shmid64_ds and shminfo64 */ #include <asm/shmbuf.h> /* * shmget() shmflg values. */ /* The bottom nine bits are the same as open(2) mode flags */ #define SHM_R 0400 /* or S_IRUGO from <linux/stat.h> */ #define SHM_W 0200 /* or S_IWUGO from <linux/stat.h> */ /* Bits 9 & 10 are IPC_CREAT and IPC_EXCL */ #define SHM_HUGETLB 04000 /* segment will use huge TLB pages */ #define SHM_NORESERVE 010000 /* don't check for reservations */ /* * Huge page size encoding when SHM_HUGETLB is specified, and a huge page * size other than the default is desired. See hugetlb_encode.h */ #define SHM_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT #define SHM_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK #define SHM_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB #define SHM_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB #define SHM_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB #define SHM_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB #define SHM_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB #define SHM_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB #define SHM_HUGE_32MB HUGETLB_FLAG_ENCODE_32MB #define SHM_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB #define SHM_HUGE_512MB HUGETLB_FLAG_ENCODE_512MB #define SHM_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB #define SHM_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB #define SHM_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB /* * shmat() shmflg values */ #define SHM_RDONLY 010000 /* read-only access */ #define SHM_RND 020000 /* round attach address to SHMLBA boundary */ #define SHM_REMAP 040000 /* take-over region on attach */ #define SHM_EXEC 0100000 /* execution access */ /* super user shmctl commands */ #define SHM_LOCK 11 #define SHM_UNLOCK 12 /* ipcs ctl commands */ #define SHM_STAT 13 #define SHM_INFO 14 #define SHM_STAT_ANY 15 /* Obsolete, used only for backwards compatibility */ struct shminfo { int shmmax; int shmmin; int shmmni; int shmseg; int shmall; }; struct shm_info { int used_ids; __kernel_ulong_t shm_tot; /* total allocated shm */ __kernel_ulong_t shm_rss; /* total resident shm */ __kernel_ulong_t shm_swp; /* total swapped shm */ __kernel_ulong_t swap_attempts; __kernel_ulong_t swap_successes; }; #endif /* _LINUX_SHM_H_ */