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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */2#ifndef _UAPI_LINUX_FUTEX_H3#define _UAPI_LINUX_FUTEX_H4 5#include <linux/compiler.h>6#include <linux/types.h>7 8/* Second argument to futex syscall */9 10 11#define FUTEX_WAIT 012#define FUTEX_WAKE 113#define FUTEX_FD 214#define FUTEX_REQUEUE 315#define FUTEX_CMP_REQUEUE 416#define FUTEX_WAKE_OP 517#define FUTEX_LOCK_PI 618#define FUTEX_UNLOCK_PI 719#define FUTEX_TRYLOCK_PI 820#define FUTEX_WAIT_BITSET 921#define FUTEX_WAKE_BITSET 1022#define FUTEX_WAIT_REQUEUE_PI 1123#define FUTEX_CMP_REQUEUE_PI 1224#define FUTEX_LOCK_PI2 1325 26#define FUTEX_PRIVATE_FLAG 12827#define FUTEX_CLOCK_REALTIME 25628#define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME)29 30#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)31#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)32#define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG)33#define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG)34#define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG)35#define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG)36#define FUTEX_LOCK_PI2_PRIVATE (FUTEX_LOCK_PI2 | FUTEX_PRIVATE_FLAG)37#define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG)38#define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG)39#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG)40#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG)41#define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \42 FUTEX_PRIVATE_FLAG)43#define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \44 FUTEX_PRIVATE_FLAG)45 46/*47 * Flags for futex2 syscalls.48 *49 * NOTE: these are not pure flags, they can also be seen as:50 *51 * union {52 * u32 flags;53 * struct {54 * u32 size : 2,55 * numa : 1,56 * : 4,57 * private : 1;58 * };59 * };60 */61#define FUTEX2_SIZE_U8 0x0062#define FUTEX2_SIZE_U16 0x0163#define FUTEX2_SIZE_U32 0x0264#define FUTEX2_SIZE_U64 0x0365#define FUTEX2_NUMA 0x0466 /* 0x08 */67 /* 0x10 */68 /* 0x20 */69 /* 0x40 */70#define FUTEX2_PRIVATE FUTEX_PRIVATE_FLAG71 72#define FUTEX2_SIZE_MASK 0x0373 74/* do not use */75#define FUTEX_32 FUTEX2_SIZE_U32 /* historical accident :-( */76 77/*78 * Max numbers of elements in a futex_waitv array79 */80#define FUTEX_WAITV_MAX 12881 82/**83 * struct futex_waitv - A waiter for vectorized wait84 * @val: Expected value at uaddr85 * @uaddr: User address to wait on86 * @flags: Flags for this waiter87 * @__reserved: Reserved member to preserve data alignment. Should be 0.88 */89struct futex_waitv {90 __u64 val;91 __u64 uaddr;92 __u32 flags;93 __u32 __reserved;94};95 96/*97 * Support for robust futexes: the kernel cleans up held futexes at98 * thread exit time.99 */100 101/*102 * Per-lock list entry - embedded in user-space locks, somewhere close103 * to the futex field. (Note: user-space uses a double-linked list to104 * achieve O(1) list add and remove, but the kernel only needs to know105 * about the forward link)106 *107 * NOTE: this structure is part of the syscall ABI, and must not be108 * changed.109 */110struct robust_list {111 struct robust_list __user *next;112};113 114/*115 * Per-thread list head:116 *117 * NOTE: this structure is part of the syscall ABI, and must only be118 * changed if the change is first communicated with the glibc folks.119 * (When an incompatible change is done, we'll increase the structure120 * size, which glibc will detect)121 */122struct robust_list_head {123 /*124 * The head of the list. Points back to itself if empty:125 */126 struct robust_list list;127 128 /*129 * This relative offset is set by user-space, it gives the kernel130 * the relative position of the futex field to examine. This way131 * we keep userspace flexible, to freely shape its data-structure,132 * without hardcoding any particular offset into the kernel:133 */134 long futex_offset;135 136 /*137 * The death of the thread may race with userspace setting138 * up a lock's links. So to handle this race, userspace first139 * sets this field to the address of the to-be-taken lock,140 * then does the lock acquire, and then adds itself to the141 * list, and then clears this field. Hence the kernel will142 * always have full knowledge of all locks that the thread143 * _might_ have taken. We check the owner TID in any case,144 * so only truly owned locks will be handled.145 */146 struct robust_list __user *list_op_pending;147};148 149/*150 * Are there any waiters for this robust futex:151 */152#define FUTEX_WAITERS 0x80000000153 154/*155 * The kernel signals via this bit that a thread holding a futex156 * has exited without unlocking the futex. The kernel also does157 * a FUTEX_WAKE on such futexes, after setting the bit, to wake158 * up any possible waiters:159 */160#define FUTEX_OWNER_DIED 0x40000000161 162/*163 * The rest of the robust-futex field is for the TID:164 */165#define FUTEX_TID_MASK 0x3fffffff166 167/*168 * This limit protects against a deliberately circular list.169 * (Not worth introducing an rlimit for it)170 */171#define ROBUST_LIST_LIMIT 2048172 173/*174 * bitset with all bits set for the FUTEX_xxx_BITSET OPs to request a175 * match of any bit.176 */177#define FUTEX_BITSET_MATCH_ANY 0xffffffff178 179 180#define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */181#define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */182#define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */183#define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */184#define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */185 186#define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */187 188#define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */189#define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */190#define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */191#define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */192#define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */193#define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */194 195/* FUTEX_WAKE_OP will perform atomically196 int oldval = *(int *)UADDR2;197 *(int *)UADDR2 = oldval OP OPARG;198 if (oldval CMP CMPARG)199 wake UADDR2; */200 201#define FUTEX_OP(op, oparg, cmp, cmparg) \202 (((op & 0xf) << 28) | ((cmp & 0xf) << 24) \203 | ((oparg & 0xfff) << 12) | (cmparg & 0xfff))204 205#endif /* _UAPI_LINUX_FUTEX_H */206