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 #ifdef __KERNEL__
   7 #include <asm/page.h>
   8 #else
   9 #include <unistd.h>
  10 #endif
  11
  12 /*
  13  * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
  14  * be increased by sysctl
  15  */
  16
  17 #define SHMMAX 0x2000000                 /* max shared seg size (bytes) */
  18 #define SHMMIN 1                         /* min shared seg size (bytes) */
  19 #define SHMMNI 4096                      /* max num of segs system wide */
  20 #ifdef __KERNEL__
  21 #define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
  22 #else
  23 #define SHMALL (SHMMAX/getpagesize()*(SHMMNI/16))
  24 #endif
  25 #define SHMSEG SHMMNI                    /* max shared segs per process */
  26
  27 #ifdef __KERNEL__
  28 #include <asm/shmparam.h>
  29 #endif
  30
  31 /* Obsolete, used only for backwards compatibility and libc5 compiles */
  32 struct shmid_ds {
  33         struct ipc_perm         shm_perm;       /* operation perms */
  34         int                     shm_segsz;      /* size of segment (bytes) */
  35         __kernel_time_t         shm_atime;      /* last attach time */
  36         __kernel_time_t         shm_dtime;      /* last detach time */
  37         __kernel_time_t         shm_ctime;      /* last change time */
  38         __kernel_ipc_pid_t      shm_cpid;       /* pid of creator */
  39         __kernel_ipc_pid_t      shm_lpid;       /* pid of last operator */
  40         unsigned short          shm_nattch;     /* no. of current attaches */
  41         unsigned short          shm_unused;     /* compatibility */
  42         void                    *shm_unused2;   /* ditto - used by DIPC */
  43         void                    *shm_unused3;   /* unused */
  44 };
  45
  46 /* Include the definition of shmid64_ds and shminfo64 */
  47 #include <asm/shmbuf.h>
  48
  49 /* permission flag for shmget */
  50 #define SHM_R           0400    /* or S_IRUGO from <linux/stat.h> */
  51 #define SHM_W           0200    /* or S_IWUGO from <linux/stat.h> */
  52
  53 /* mode for attach */
  54 #define SHM_RDONLY      010000  /* read-only access */
  55 #define SHM_RND         020000  /* round attach address to SHMLBA boundary */
  56 #define SHM_REMAP       040000  /* take-over region on attach */
  57 #define SHM_EXEC        0100000 /* execution access */
  58
  59 /* super user shmctl commands */
  60 #define SHM_LOCK        11
  61 #define SHM_UNLOCK      12
  62
  63 /* ipcs ctl commands */
  64 #define SHM_STAT        13
  65 #define SHM_INFO        14
  66
  67 /* Obsolete, used only for backwards compatibility */
  68 struct  shminfo {
  69         int shmmax;
  70         int shmmin;
  71         int shmmni;
  72         int shmseg;
  73         int shmall;
  74 };
  75
  76 struct shm_info {
  77         int used_ids;
  78         unsigned long shm_tot;  /* total allocated shm */
  79         unsigned long shm_rss;  /* total resident shm */
  80         unsigned long shm_swp;  /* total swapped shm */
  81         unsigned long swap_attempts;
  82         unsigned long swap_successes;
  83 };
  84
  85 #ifdef __KERNEL__
  86 struct shmid_kernel /* private to the kernel */
  87 {
  88         struct kern_ipc_perm    shm_perm;
  89         struct file *           shm_file;
  90         unsigned long           shm_nattch;
  91         unsigned long           shm_segsz;
  92         time_t                  shm_atim;
  93         time_t                  shm_dtim;
  94         time_t                  shm_ctim;
  95         pid_t                   shm_cprid;
  96         pid_t                   shm_lprid;
  97         struct user_struct      *mlock_user;
  98
  99         /* The task created the shm object.  NULL if the task is dead. */
 100         struct task_struct      *shm_creator;
 101 };
 102
 103 /* shm_mode upper byte flags */
 104 #define SHM_DEST        01000   /* segment will be destroyed on last detach */
 105 #define SHM_LOCKED      02000   /* segment will not be swapped */
 106 #define SHM_HUGETLB     04000   /* segment will use huge TLB pages */
 107 #define SHM_NORESERVE   010000  /* don't check for reservations */
 108
 109 #ifdef CONFIG_SYSVIPC
 110 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
 111 extern int is_file_shm_hugepages(struct file *file);
 112 extern void exit_shm(struct task_struct *task);
 113 #else
 114 static inline long do_shmat(int shmid, char __user *shmaddr,
 115                                 int shmflg, unsigned long *addr)
 116 {
 117         return -ENOSYS;
 118 }
 119 static inline int is_file_shm_hugepages(struct file *file)
 120 {
 121         return 0;
 122 }
 123 static inline void exit_shm(struct task_struct *task)
 124 {
 125 }
 126 #endif
 127
 128 #endif /* __KERNEL__ */
 129
 130 #endif /* _LINUX_SHM_H_ */