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