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 int nbuckets; 29 }; 30 31 /** 32 * futex_syscall() - SYS_futex syscall wrapper 33 * @uaddr: address of first futex 34 * @op: futex op code 35 * @val: typically expected value of uaddr, but varies by op 36 * @timeout: typically an absolute struct timespec (except where noted 37 * otherwise). Overloaded by some ops 38 * @uaddr2: address of second futex for some ops 39 * @val3: varies by op 40 * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG 41 * 42 * futex_syscall() is used by all the following futex op wrappers. It can also be 43 * used for misuse and abuse testing. Generally, the specific op wrappers 44 * should be used instead. 45 * 46 * These argument descriptions are the defaults for all 47 * like-named arguments in the following wrappers except where noted below. 48 */ 49 static inline int 50 futex_syscall(volatile u_int32_t *uaddr, int op, u_int32_t val, struct timespec *timeout, 51 volatile u_int32_t *uaddr2, int val3, int opflags) 52 { 53 return syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3); 54 } 55 56 static inline int 57 futex_syscall_nr_requeue(volatile u_int32_t *uaddr, int op, u_int32_t val, int nr_requeue, 58 volatile u_int32_t *uaddr2, int val3, int opflags) 59 { 60 return syscall(SYS_futex, uaddr, op | opflags, val, nr_requeue, uaddr2, val3); 61 } 62 63 /** 64 * futex_wait() - block on uaddr with optional timeout 65 * @timeout: relative timeout 66 */ 67 static inline int 68 futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags) 69 { 70 return futex_syscall(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); 71 } 72 73 /** 74 * futex_wake() - wake one or more tasks blocked on uaddr 75 * @nr_wake: wake up to this many tasks 76 */ 77 static inline int 78 futex_wake(u_int32_t *uaddr, int nr_wake, int opflags) 79 { 80 return futex_syscall(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); 81 } 82 83 /** 84 * futex_lock_pi() - block on uaddr as a PI mutex 85 */ 86 static inline int 87 futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags) 88 { 89 return futex_syscall(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags); 90 } 91 92 /** 93 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter 94 */ 95 static inline int 96 futex_unlock_pi(u_int32_t *uaddr, int opflags) 97 { 98 return futex_syscall(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags); 99 } 100 101 /** 102 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2 103 * @nr_wake: wake up to this many tasks 104 * @nr_requeue: requeue up to this many tasks 105 */ 106 static inline int 107 futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake, 108 int nr_requeue, int opflags) 109 { 110 return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2, 111 val, opflags); 112 } 113 114 /** 115 * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2 116 * @uaddr: non-PI futex source 117 * @uaddr2: PI futex target 118 * 119 * This is the first half of the requeue_pi mechanism. It shall always be 120 * paired with futex_cmp_requeue_pi(). 121 */ 122 static inline int 123 futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, 124 struct timespec *timeout, int opflags) 125 { 126 return futex_syscall(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0, 127 opflags); 128 } 129 130 /** 131 * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2 132 * @uaddr: non-PI futex source 133 * @uaddr2: PI futex target 134 * @nr_requeue: requeue up to this many tasks 135 * 136 * This is the second half of the requeue_pi mechanism. It shall always be 137 * paired with futex_wait_requeue_pi(). The first waker is always awoken. 138 */ 139 static inline int 140 futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, 141 int nr_requeue, int opflags) 142 { 143 return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2, 144 val, opflags); 145 } 146 147 void futex_set_nbuckets_param(struct bench_futex_parameters *params); 148 void futex_print_nbuckets(struct bench_futex_parameters *params); 149 150 #endif /* _FUTEX_H */ 151