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