1 #ifndef _LINUX_SHM_H_
2 #define _LINUX_SHM_H_
3
4 #include <linux/list.h>
5 #include <asm/page.h>
6 #include <uapi/linux/shm.h>
7 #include <asm/shmparam.h>
8
9 struct shmid_kernel /* private to the kernel */
10 {
11 struct kern_ipc_perm shm_perm;
12 struct file *shm_file;
13 unsigned long shm_nattch;
14 unsigned long shm_segsz;
15 time_t shm_atim;
16 time_t shm_dtim;
17 time_t shm_ctim;
18 pid_t shm_cprid;
19 pid_t shm_lprid;
20 struct user_struct *mlock_user;
21
22 /*
23 * The task created the shm object, for
24 * task_lock(shp->shm_creator)
25 */
26 struct task_struct *shm_creator;
27
28 /*
29 * List by creator. task_lock(->shm_creator) required for read/write.
30 * If list_empty(), then the creator is dead already.
31 */
32 struct list_head shm_clist;
33 struct ipc_namespace *ns;
34 };
35
36 /* shm_mode upper byte flags */
37 #define SHM_DEST 01000 /* segment will be destroyed on last detach */
38 #define SHM_LOCKED 02000 /* segment will not be swapped */
39 #define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
40 #define SHM_NORESERVE 010000 /* don't check for reservations */
41
42 /* Bits [26:31] are reserved */
43
44 /*
45 * When SHM_HUGETLB is set bits [26:31] encode the log2 of the huge page size.
46 * This gives us 6 bits, which is enough until someone invents 128 bit address
47 * spaces.
48 *
49 * Assume these are all power of twos.
50 * When 0 use the default page size.
51 */
52 #define SHM_HUGE_SHIFT 26
53 #define SHM_HUGE_MASK 0x3f
54 #define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT)
55 #define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT)
56
57 #ifdef CONFIG_SYSVIPC
58 struct sysv_shm {
59 struct list_head shm_clist;
60 };
61
62 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
63 unsigned long shmlba);
64 int is_file_shm_hugepages(struct file *file);
65 void exit_shm(struct task_struct *task);
66 #define shm_init_task(task) INIT_LIST_HEAD(&(task)->sysvshm.shm_clist)
67 #else
68 struct sysv_shm {
69 /* empty */
70 };
71
do_shmat(int shmid,char __user * shmaddr,int shmflg,unsigned long * addr,unsigned long shmlba)72 static inline long do_shmat(int shmid, char __user *shmaddr,
73 int shmflg, unsigned long *addr,
74 unsigned long shmlba)
75 {
76 return -ENOSYS;
77 }
is_file_shm_hugepages(struct file * file)78 static inline int is_file_shm_hugepages(struct file *file)
79 {
80 return 0;
81 }
exit_shm(struct task_struct * task)82 static inline void exit_shm(struct task_struct *task)
83 {
84 }
shm_init_task(struct task_struct * task)85 static inline void shm_init_task(struct task_struct *task)
86 {
87 }
88 #endif
89
90 #endif /* _LINUX_SHM_H_ */
91