1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Glibc independent futex library for testing kernel functionality. 4 * Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com> 5 * http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/ 6 */ 7 8 #ifndef _FUTEX_H 9 #define _FUTEX_H 10 11 #include <unistd.h> 12 #include <sys/syscall.h> 13 #include <sys/types.h> 14 #include <linux/futex.h> 15 16 struct bench_futex_parameters { 17 bool silent; 18 bool fshared; 19 bool mlockall; 20 bool multi; /* lock-pi */ 21 bool pi; /* requeue-pi */ 22 bool broadcast; /* requeue */ 23 unsigned int runtime; /* seconds*/ 24 unsigned int nthreads; 25 unsigned int nfutexes; 26 unsigned int nwakes; 27 unsigned int nrequeue; 28 }; 29 30 /** 31 * futex() - SYS_futex syscall wrapper 32 * @uaddr: address of first futex 33 * @op: futex op code 34 * @val: typically expected value of uaddr, but varies by op 35 * @timeout: typically an absolute struct timespec (except where noted 36 * otherwise). Overloaded by some ops 37 * @uaddr2: address of second futex for some ops 38 * @val3: varies by op 39 * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG 40 * 41 * futex() is used by all the following futex op wrappers. It can also be 42 * used for misuse and abuse testing. Generally, the specific op wrappers 43 * should be used instead. It is a macro instead of an static inline function as 44 * some of the types over overloaded (timeout is used for nr_requeue for 45 * example). 46 * 47 * These argument descriptions are the defaults for all 48 * like-named arguments in the following wrappers except where noted below. 49 */ 50 #define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \ 51 syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3) 52 53 /** 54 * futex_wait() - block on uaddr with optional timeout 55 * @timeout: relative timeout 56 */ 57 static inline int 58 futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags) 59 { 60 return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); 61 } 62 63 /** 64 * futex_wake() - wake one or more tasks blocked on uaddr 65 * @nr_wake: wake up to this many tasks 66 */ 67 static inline int 68 futex_wake(u_int32_t *uaddr, int nr_wake, int opflags) 69 { 70 return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); 71 } 72 73 /** 74 * futex_lock_pi() - block on uaddr as a PI mutex 75 */ 76 static inline int 77 futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags) 78 { 79 return futex(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags); 80 } 81 82 /** 83 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter 84 */ 85 static inline int 86 futex_unlock_pi(u_int32_t *uaddr, int opflags) 87 { 88 return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags); 89 } 90 91 /** 92 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2 93 * @nr_wake: wake up to this many tasks 94 * @nr_requeue: requeue up to this many tasks 95 */ 96 static inline int 97 futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake, 98 int nr_requeue, int opflags) 99 { 100 return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2, 101 val, opflags); 102 } 103 104 /** 105 * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2 106 * @uaddr: non-PI futex source 107 * @uaddr2: PI futex target 108 * 109 * This is the first half of the requeue_pi mechanism. It shall always be 110 * paired with futex_cmp_requeue_pi(). 111 */ 112 static inline int 113 futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, 114 struct timespec *timeout, int opflags) 115 { 116 return futex(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0, 117 opflags); 118 } 119 120 /** 121 * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2 122 * @uaddr: non-PI futex source 123 * @uaddr2: PI futex target 124 * @nr_requeue: requeue up to this many tasks 125 * 126 * This is the second half of the requeue_pi mechanism. It shall always be 127 * paired with futex_wait_requeue_pi(). The first waker is always awoken. 128 */ 129 static inline int 130 futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, 131 int nr_requeue, int opflags) 132 { 133 return futex(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2, 134 val, opflags); 135 } 136 137 #endif /* _FUTEX_H */ 138