LXR linux/include/linux/shm.h

   1#ifndef _LINUX_SHM_H_
   2#define _LINUX_SHM_H_
   3
   4#include <linux/ipc.h>
   5#include <linux/errno.h>
   6#include <asm/page.h>
   7
   8/*
   9 * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
  10 * be increased by sysctl
  11 */
  12
  13#define SHMMAX 0x2000000                 /* max shared seg size (bytes) */
  14#define SHMMIN 1                         /* min shared seg size (bytes) */
  15#define SHMMNI 4096                      /* max num of segs system wide */
  16#define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
  17#define SHMSEG SHMMNI                    /* max shared segs per process */
  18
  19#include <asm/shmparam.h>
  20
  21/* Obsolete, used only for backwards compatibility and libc5 compiles */
  22struct shmid_ds {
  23        struct ipc_perm         shm_perm;       /* operation perms */
  24        int                     shm_segsz;      /* size of segment (bytes) */
  25        __kernel_time_t         shm_atime;      /* last attach time */
  26        __kernel_time_t         shm_dtime;      /* last detach time */
  27        __kernel_time_t         shm_ctime;      /* last change time */
  28        __kernel_ipc_pid_t      shm_cpid;       /* pid of creator */
  29        __kernel_ipc_pid_t      shm_lpid;       /* pid of last operator */
  30        unsigned short          shm_nattch;     /* no. of current attaches */
  31        unsigned short          shm_unused;     /* compatibility */
  32        void                    *shm_unused2;   /* ditto - used by DIPC */
  33        void                    *shm_unused3;   /* unused */
  34};
  35
  36/* Include the definition of shmid64_ds and shminfo64 */
  37#include <asm/shmbuf.h>
  38
  39/* permission flag for shmget */
  40#define SHM_R           0400    /* or S_IRUGO from <linux/stat.h> */
  41#define SHM_W           0200    /* or S_IWUGO from <linux/stat.h> */
  42
  43/* mode for attach */
  44#define SHM_RDONLY      010000  /* read-only access */
  45#define SHM_RND         020000  /* round attach address to SHMLBA boundary */
  46#define SHM_REMAP       040000  /* take-over region on attach */
  47#define SHM_EXEC        0100000 /* execution access */
  48
  49/* super user shmctl commands */
  50#define SHM_LOCK        11
  51#define SHM_UNLOCK      12
  52
  53/* ipcs ctl commands */
  54#define SHM_STAT        13
  55#define SHM_INFO        14
  56
  57/* Obsolete, used only for backwards compatibility */
  58struct  shminfo {
  59        int shmmax;
  60        int shmmin;
  61        int shmmni;
  62        int shmseg;
  63        int shmall;
  64};
  65
  66struct shm_info {
  67        int used_ids;
  68        unsigned long shm_tot;  /* total allocated shm */
  69        unsigned long shm_rss;  /* total resident shm */
  70        unsigned long shm_swp;  /* total swapped shm */
  71        unsigned long swap_attempts;
  72        unsigned long swap_successes;
  73};
  74
  75#ifdef __KERNEL__
  76struct shmid_kernel /* private to the kernel */
  77{       
  78        struct kern_ipc_perm    shm_perm;
  79        struct file *           shm_file;
  80        int                     id;
  81        unsigned long           shm_nattch;
  82        unsigned long           shm_segsz;
  83        time_t                  shm_atim;
  84        time_t                  shm_dtim;
  85        time_t                  shm_ctim;
  86        pid_t                   shm_cprid;
  87        pid_t                   shm_lprid;
  88        struct user_struct      *mlock_user;
  89};
  90
  91/* shm_mode upper byte flags */
  92#define SHM_DEST        01000   /* segment will be destroyed on last detach */
  93#define SHM_LOCKED      02000   /* segment will not be swapped */
  94#define SHM_HUGETLB     04000   /* segment will use huge TLB pages */
  95#define SHM_NORESERVE   010000  /* don't check for reservations */
  96
  97#ifdef CONFIG_SYSVIPC
  98long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
  99extern int is_file_shm_hugepages(struct file *file);
 100#else
 101static inline long do_shmat(int shmid, char __user *shmaddr,
 102                                int shmflg, unsigned long *addr)
 103{
 104        return -ENOSYS;
 105}
 106static inline int is_file_shm_hugepages(struct file *file)
 107{
 108        return 0;
 109}
 110#endif
 111
 112#endif /* __KERNEL__ */
 113
 114#endif /* _LINUX_SHM_H_ */
 115