Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#ifndef _LINUX_SHM_H_
2#define _LINUX_SHM_H_
3
4#include <asm/page.h>
5#include <uapi/linux/shm.h>
6#include <asm/shmparam.h>
7
8struct shmid_kernel /* private to the kernel */
9{
10 struct kern_ipc_perm shm_perm;
11 struct file *shm_file;
12 unsigned long shm_nattch;
13 unsigned long shm_segsz;
14 time_t shm_atim;
15 time_t shm_dtim;
16 time_t shm_ctim;
17 pid_t shm_cprid;
18 pid_t shm_lprid;
19 struct user_struct *mlock_user;
20
21 /* The task created the shm object. NULL if the task is dead. */
22 struct task_struct *shm_creator;
23};
24
25/* shm_mode upper byte flags */
26#define SHM_DEST 01000 /* segment will be destroyed on last detach */
27#define SHM_LOCKED 02000 /* segment will not be swapped */
28#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */
29#define SHM_NORESERVE 010000 /* don't check for reservations */
30
31/* Bits [26:31] are reserved */
32
33/*
34 * When SHM_HUGETLB is set bits [26:31] encode the log2 of the huge page size.
35 * This gives us 6 bits, which is enough until someone invents 128 bit address
36 * spaces.
37 *
38 * Assume these are all power of twos.
39 * When 0 use the default page size.
40 */
41#define SHM_HUGE_SHIFT 26
42#define SHM_HUGE_MASK 0x3f
43#define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT)
44#define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT)
45
46#ifdef CONFIG_SYSVIPC
47long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
48 unsigned long shmlba);
49extern int is_file_shm_hugepages(struct file *file);
50extern void exit_shm(struct task_struct *task);
51#else
52static inline long do_shmat(int shmid, char __user *shmaddr,
53 int shmflg, unsigned long *addr,
54 unsigned long shmlba)
55{
56 return -ENOSYS;
57}
58static inline int is_file_shm_hugepages(struct file *file)
59{
60 return 0;
61}
62static inline void exit_shm(struct task_struct *task)
63{
64}
65#endif
66
67#endif /* _LINUX_SHM_H_ */