/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_SHM_H_
#define _UAPI_LINUX_SHM_H_

#include <linux/ipc.h>
#include <linux/errno.h>
#include <asm-generic/hugetlb_encode.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 /* _UAPI_LINUX_SHM_H_ */