1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_FUTEX_H 3 #define _LINUX_FUTEX_H 4 5 #include <linux/ktime.h> 6 #include <uapi/linux/futex.h> 7 8 struct inode; 9 struct mm_struct; 10 struct task_struct; 11 12 extern int 13 handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi); 14 15 /* 16 * Futexes are matched on equal values of this key. 17 * The key type depends on whether it's a shared or private mapping. 18 * Don't rearrange members without looking at hash_futex(). 19 * 20 * offset is aligned to a multiple of sizeof(u32) (== 4) by definition. 21 * We use the two low order bits of offset to tell what is the kind of key : 22 * 00 : Private process futex (PTHREAD_PROCESS_PRIVATE) 23 * (no reference on an inode or mm) 24 * 01 : Shared futex (PTHREAD_PROCESS_SHARED) 25 * mapped on a file (reference on the underlying inode) 26 * 10 : Shared futex (PTHREAD_PROCESS_SHARED) 27 * (but private mapping on an mm, and reference taken on it) 28 */ 29 30 #define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */ 31 #define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */ 32 33 union futex_key { 34 struct { 35 unsigned long pgoff; 36 struct inode *inode; 37 int offset; 38 } shared; 39 struct { 40 unsigned long address; 41 struct mm_struct *mm; 42 int offset; 43 } private; 44 struct { 45 unsigned long word; 46 void *ptr; 47 int offset; 48 } both; 49 }; 50 51 #define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } } 52 53 #ifdef CONFIG_FUTEX 54 extern void exit_robust_list(struct task_struct *curr); 55 56 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, 57 u32 __user *uaddr2, u32 val2, u32 val3); 58 #ifdef CONFIG_HAVE_FUTEX_CMPXCHG 59 #define futex_cmpxchg_enabled 1 60 #else 61 extern int futex_cmpxchg_enabled; 62 #endif 63 #else 64 static inline void exit_robust_list(struct task_struct *curr) 65 { 66 } 67 68 static inline long do_futex(u32 __user *uaddr, int op, u32 val, 69 ktime_t *timeout, u32 __user *uaddr2, 70 u32 val2, u32 val3) 71 { 72 return -EINVAL; 73 } 74 #endif 75 76 #ifdef CONFIG_FUTEX_PI 77 extern void exit_pi_state_list(struct task_struct *curr); 78 #else 79 static inline void exit_pi_state_list(struct task_struct *curr) 80 { 81 } 82 #endif 83 84 #endif 85