include/uapi/linux/shm.h

   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_256MB  HUGETLB_FLAG_ENCODE_256MB
  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
  89 /* Obsolete, used only for backwards compatibility */
  90 struct  shminfo {
  91         int shmmax;
  92         int shmmin;
  93         int shmmni;
  94         int shmseg;
  95         int shmall;
  96 };
  97
  98 struct shm_info {
  99         int used_ids;
 100         __kernel_ulong_t shm_tot;       /* total allocated shm */
 101         __kernel_ulong_t shm_rss;       /* total resident shm */
 102         __kernel_ulong_t shm_swp;       /* total swapped shm */
 103         __kernel_ulong_t swap_attempts;
 104         __kernel_ulong_t swap_successes;
 105 };
 106
 107
 108 #endif /* _UAPI_LINUX_SHM_H_ */