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 */
  22 struct 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 */
  58 struct  shminfo {
  59         int shmmax;
  60         int shmmin;
  61         int shmmni;
  62         int shmseg;
  63         int shmall;
  64 };
  65
  66 struct 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__
  76 struct 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
  98 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
  99 extern int is_file_shm_hugepages(struct file *file);
 100 #else
 101 static inline long do_shmat(int shmid, char __user *shmaddr,
 102                                 int shmflg, unsigned long *addr)
 103 {
 104         return -ENOSYS;
 105 }
 106 static 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_ */