diff options
Diffstat (limited to '0001-futex.patch')
| -rw-r--r-- | 0001-futex.patch | 1028 |
1 files changed, 1028 insertions, 0 deletions
diff --git a/0001-futex.patch b/0001-futex.patch new file mode 100644 index 000000000000..72bf55a8f28d --- /dev/null +++ b/0001-futex.patch @@ -0,0 +1,1028 @@ +From 3c0db5afb3180941bf51dd7c12541514d774a250 Mon Sep 17 00:00:00 2001 +From: Gabriel Krisman Bertazi <krisman@collabora.com> +Date: Thu, 13 Feb 2020 18:45:22 -0300 +Subject: [PATCH 1/4] futex: Implement mechanism to wait on any of several + futexes +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +This is a new futex operation, called FUTEX_WAIT_MULTIPLE, which allows +a thread to wait on several futexes at the same time, and be awoken by +any of them. In a sense, it implements one of the features that was +supported by pooling on the old FUTEX_FD interface. + +The use case lies in the Wine implementation of the Windows NT interface +WaitMultipleObjects. This Windows API function allows a thread to sleep +waiting on the first of a set of event sources (mutexes, timers, signal, +console input, etc) to signal. Considering this is a primitive +synchronization operation for Windows applications, being able to quickly +signal events on the producer side, and quickly go to sleep on the +consumer side is essential for good performance of those running over Wine. + +Wine developers have an implementation that uses eventfd, but it suffers +from FD exhaustion (there is applications that go to the order of +multi-milion FDs), and higher CPU utilization than this new operation. + +The futex list is passed as an array of `struct futex_wait_block` +(pointer, value, bitset) to the kernel, which will enqueue all of them +and sleep if none was already triggered. It returns a hint of which +futex caused the wake up event to userspace, but the hint doesn't +guarantee that is the only futex triggered. Before calling the syscall +again, userspace should traverse the list, trying to re-acquire any of +the other futexes, to prevent an immediate -EWOULDBLOCK return code from +the kernel. + +This was tested using three mechanisms: + +1) By reimplementing FUTEX_WAIT in terms of FUTEX_WAIT_MULTIPLE and +running the unmodified tools/testing/selftests/futex and a full linux +distro on top of this kernel. + +2) By an example code that exercises the FUTEX_WAIT_MULTIPLE path on a +multi-threaded, event-handling setup. + +3) By running the Wine fsync with Valve's Proton compatibility code +implementation and executing multi-threaded applications, in particular +modern games, on top of this implementation. + +Changes were tested for the following ABIs: x86_64, i386 and x32. +Support for x32 applications is not implemented since it would +take a major rework adding a new entry point and splitting the current +futex 64 entry point in two and we can't change the current x32 syscall +number without breaking user space compatibility. + +CC: Steven Rostedt <rostedt@goodmis.org> +Cc: Richard Yao <ryao@gentoo.org> +Cc: Thomas Gleixner <tglx@linutronix.de> +Cc: Peter Zijlstra <peterz@infradead.org> +Co-developed-by: Zebediah Figura <z.figura12@gmail.com> +Signed-off-by: Zebediah Figura <z.figura12@gmail.com> +Co-developed-by: Steven Noonan <steven@valvesoftware.com> +Signed-off-by: Steven Noonan <steven@valvesoftware.com> +Co-developed-by: Pierre-Loup A. Griffais <pgriffais@valvesoftware.com> +Signed-off-by: Pierre-Loup A. Griffais <pgriffais@valvesoftware.com> +Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> +[Added compatibility code] +Co-developed-by: André Almeida <andrealmeid@collabora.com> +Signed-off-by: André Almeida <andrealmeid@collabora.com> +--- + include/uapi/linux/futex.h | 20 ++ + kernel/futex.c | 363 ++++++++++++++++++++++++++++++++++++- + 2 files changed, 379 insertions(+), 4 deletions(-) + +diff --git a/include/uapi/linux/futex.h b/include/uapi/linux/futex.h +index a89eb0acc..a3e760886 100644 +--- a/include/uapi/linux/futex.h ++++ b/include/uapi/linux/futex.h +@@ -21,6 +21,7 @@ + #define FUTEX_WAKE_BITSET 10 + #define FUTEX_WAIT_REQUEUE_PI 11 + #define FUTEX_CMP_REQUEUE_PI 12 ++#define FUTEX_WAIT_MULTIPLE 31 + + #define FUTEX_PRIVATE_FLAG 128 + #define FUTEX_CLOCK_REALTIME 256 +@@ -40,6 +41,8 @@ + FUTEX_PRIVATE_FLAG) + #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \ + FUTEX_PRIVATE_FLAG) ++#define FUTEX_WAIT_MULTIPLE_PRIVATE (FUTEX_WAIT_MULTIPLE | \ ++ FUTEX_PRIVATE_FLAG) + + /* + * Support for robust futexes: the kernel cleans up held futexes at +@@ -150,4 +153,21 @@ struct robust_list_head { + (((op & 0xf) << 28) | ((cmp & 0xf) << 24) \ + | ((oparg & 0xfff) << 12) | (cmparg & 0xfff)) + ++/* ++ * Maximum number of multiple futexes to wait for ++ */ ++#define FUTEX_MULTIPLE_MAX_COUNT 128 ++ ++/** ++ * struct futex_wait_block - Block of futexes to be waited for ++ * @uaddr: User address of the futex ++ * @val: Futex value expected by userspace ++ * @bitset: Bitset for the optional bitmasked wakeup ++ */ ++struct futex_wait_block { ++ __u32 __user *uaddr; ++ __u32 val; ++ __u32 bitset; ++}; ++ + #endif /* _UAPI_LINUX_FUTEX_H */ +diff --git a/kernel/futex.c b/kernel/futex.c +index b59532862..2fbfb0b80 100644 +--- a/kernel/futex.c ++++ b/kernel/futex.c +@@ -214,6 +214,8 @@ struct futex_pi_state { + * @rt_waiter: rt_waiter storage for use with requeue_pi + * @requeue_pi_key: the requeue_pi target futex key + * @bitset: bitset for the optional bitmasked wakeup ++ * @uaddr: userspace address of futex ++ * @uval: expected futex's value + * + * We use this hashed waitqueue, instead of a normal wait_queue_entry_t, so + * we can wake only the relevant ones (hashed queues may be shared). +@@ -236,6 +238,8 @@ struct futex_q { + struct rt_mutex_waiter *rt_waiter; + union futex_key *requeue_pi_key; + u32 bitset; ++ u32 __user *uaddr; ++ u32 uval; + } __randomize_layout; + + static const struct futex_q futex_q_init = { +@@ -2346,6 +2350,29 @@ static int unqueue_me(struct futex_q *q) + return ret; + } + ++/** ++ * unqueue_multiple() - Remove several futexes from their futex_hash_bucket ++ * @q: The list of futexes to unqueue ++ * @count: Number of futexes in the list ++ * ++ * Helper to unqueue a list of futexes. This can't fail. ++ * ++ * Return: ++ * - >=0 - Index of the last futex that was awoken; ++ * - -1 - If no futex was awoken ++ */ ++static int unqueue_multiple(struct futex_q *q, int count) ++{ ++ int ret = -1; ++ int i; ++ ++ for (i = 0; i < count; i++) { ++ if (!unqueue_me(&q[i])) ++ ret = i; ++ } ++ return ret; ++} ++ + /* + * PI futexes can not be requeued and must remove themself from the + * hash bucket. The hash bucket lock (i.e. lock_ptr) is held on entry +@@ -2709,6 +2736,211 @@ static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, + return ret; + } + ++/** ++ * futex_wait_multiple_setup() - Prepare to wait and enqueue multiple futexes ++ * @qs: The corresponding futex list ++ * @count: The size of the lists ++ * @flags: Futex flags (FLAGS_SHARED, etc.) ++ * @awaken: Index of the last awoken futex ++ * ++ * Prepare multiple futexes in a single step and enqueue them. This may fail if ++ * the futex list is invalid or if any futex was already awoken. On success the ++ * task is ready to interruptible sleep. ++ * ++ * Return: ++ * - 1 - One of the futexes was awaken by another thread ++ * - 0 - Success ++ * - <0 - -EFAULT, -EWOULDBLOCK or -EINVAL ++ */ ++static int futex_wait_multiple_setup(struct futex_q *qs, int count, ++ unsigned int flags, int *awaken) ++{ ++ struct futex_hash_bucket *hb; ++ int ret, i; ++ u32 uval; ++ ++ /* ++ * Enqueuing multiple futexes is tricky, because we need to ++ * enqueue each futex in the list before dealing with the next ++ * one to avoid deadlocking on the hash bucket. But, before ++ * enqueuing, we need to make sure that current->state is ++ * TASK_INTERRUPTIBLE, so we don't absorb any awake events, which ++ * cannot be done before the get_futex_key of the next key, ++ * because it calls get_user_pages, which can sleep. Thus, we ++ * fetch the list of futexes keys in two steps, by first pinning ++ * all the memory keys in the futex key, and only then we read ++ * each key and queue the corresponding futex. ++ */ ++retry: ++ for (i = 0; i < count; i++) { ++ qs[i].key = FUTEX_KEY_INIT; ++ ret = get_futex_key(qs[i].uaddr, flags & FLAGS_SHARED, ++ &qs[i].key, FUTEX_READ); ++ if (unlikely(ret)) { ++ for (--i; i >= 0; i--) ++ put_futex_key(&qs[i].key); ++ return ret; ++ } ++ } ++ ++ set_current_state(TASK_INTERRUPTIBLE); ++ ++ for (i = 0; i < count; i++) { ++ struct futex_q *q = &qs[i]; ++ ++ hb = queue_lock(q); ++ ++ ret = get_futex_value_locked(&uval, q->uaddr); ++ if (ret) { ++ /* ++ * We need to try to handle the fault, which ++ * cannot be done without sleep, so we need to ++ * undo all the work already done, to make sure ++ * we don't miss any wake ups. Therefore, clean ++ * up, handle the fault and retry from the ++ * beginning. ++ */ ++ queue_unlock(hb); ++ ++ /* ++ * Keys 0..(i-1) are implicitly put ++ * on unqueue_multiple. ++ */ ++ put_futex_key(&q->key); ++ ++ *awaken = unqueue_multiple(qs, i); ++ ++ __set_current_state(TASK_RUNNING); ++ ++ /* ++ * On a real fault, prioritize the error even if ++ * some other futex was awoken. Userspace gave ++ * us a bad address, -EFAULT them. ++ */ ++ ret = get_user(uval, q->uaddr); ++ if (ret) ++ return ret; ++ ++ /* ++ * Even if the page fault was handled, If ++ * something was already awaken, we can safely ++ * give up and succeed to give a hint for userspace to ++ * acquire the right futex faster. ++ */ ++ if (*awaken >= 0) ++ return 1; ++ ++ goto retry; ++ } ++ ++ if (uval != q->uval) { ++ queue_unlock(hb); ++ ++ put_futex_key(&qs[i].key); ++ ++ /* ++ * If something was already awaken, we can ++ * safely ignore the error and succeed. ++ */ ++ *awaken = unqueue_multiple(qs, i); ++ __set_current_state(TASK_RUNNING); ++ if (*awaken >= 0) ++ return 1; ++ ++ return -EWOULDBLOCK; ++ } ++ ++ /* ++ * The bucket lock can't be held while dealing with the ++ * next futex. Queue each futex at this moment so hb can ++ * be unlocked. ++ */ ++ queue_me(&qs[i], hb); ++ } ++ return 0; ++} ++ ++/** ++ * futex_wait_multiple() - Prepare to wait on and enqueue several futexes ++ * @qs: The list of futexes to wait on ++ * @op: Operation code from futex's syscall ++ * @count: The number of objects ++ * @abs_time: Timeout before giving up and returning to userspace ++ * ++ * Entry point for the FUTEX_WAIT_MULTIPLE futex operation, this function ++ * sleeps on a group of futexes and returns on the first futex that ++ * triggered, or after the timeout has elapsed. ++ * ++ * Return: ++ * - >=0 - Hint to the futex that was awoken ++ * - <0 - On error ++ */ ++static int futex_wait_multiple(struct futex_q *qs, int op, ++ u32 count, ktime_t *abs_time) ++{ ++ struct hrtimer_sleeper timeout, *to; ++ int ret, flags = 0, hint = 0; ++ unsigned int i; ++ ++ if (!(op & FUTEX_PRIVATE_FLAG)) ++ flags |= FLAGS_SHARED; ++ ++ if (op & FUTEX_CLOCK_REALTIME) ++ flags |= FLAGS_CLOCKRT; ++ ++ to = futex_setup_timer(abs_time, &timeout, flags, 0); ++ while (1) { ++ ret = futex_wait_multiple_setup(qs, count, flags, &hint); ++ if (ret) { ++ if (ret > 0) { ++ /* A futex was awaken during setup */ ++ ret = hint; ++ } ++ break; ++ } ++ ++ if (to) ++ hrtimer_start_expires(&to->timer, HRTIMER_MODE_ABS); ++ ++ /* ++ * Avoid sleeping if another thread already tried to ++ * wake us. ++ */ ++ for (i = 0; i < count; i++) { ++ if (plist_node_empty(&qs[i].list)) ++ break; ++ } ++ ++ if (i == count && (!to || to->task)) ++ freezable_schedule(); ++ ++ ret = unqueue_multiple(qs, count); ++ ++ __set_current_state(TASK_RUNNING); ++ ++ if (ret >= 0) ++ break; ++ if (to && !to->task) { ++ ret = -ETIMEDOUT; ++ break; ++ } else if (signal_pending(current)) { ++ ret = -ERESTARTSYS; ++ break; ++ } ++ /* ++ * The final case is a spurious wakeup, for ++ * which just retry. ++ */ ++ } ++ ++ if (to) { ++ hrtimer_cancel(&to->timer); ++ destroy_hrtimer_on_stack(&to->timer); ++ } ++ ++ return ret; ++} ++ + static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, + ktime_t *abs_time, u32 bitset) + { +@@ -3833,6 +4065,43 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, + return -ENOSYS; + } + ++/** ++ * futex_read_wait_block - Read an array of futex_wait_block from userspace ++ * @uaddr: Userspace address of the block ++ * @count: Number of blocks to be read ++ * ++ * This function creates and allocate an array of futex_q (we zero it to ++ * initialize the fields) and then, for each futex_wait_block element from ++ * userspace, fill a futex_q element with proper values. ++ */ ++inline struct futex_q *futex_read_wait_block(u32 __user *uaddr, u32 count) ++{ ++ unsigned int i; ++ struct futex_q *qs; ++ struct futex_wait_block fwb; ++ struct futex_wait_block __user *entry = ++ (struct futex_wait_block __user *)uaddr; ++ ++ if (!count || count > FUTEX_MULTIPLE_MAX_COUNT) ++ return ERR_PTR(-EINVAL); ++ ++ qs = kcalloc(count, sizeof(*qs), GFP_KERNEL); ++ if (!qs) ++ return ERR_PTR(-ENOMEM); ++ ++ for (i = 0; i < count; i++) { ++ if (copy_from_user(&fwb, &entry[i], sizeof(fwb))) { ++ kfree(qs); ++ return ERR_PTR(-EFAULT); ++ } ++ ++ qs[i].uaddr = fwb.uaddr; ++ qs[i].uval = fwb.val; ++ qs[i].bitset = fwb.bitset; ++ } ++ ++ return qs; ++} + + SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, + struct __kernel_timespec __user *, utime, u32 __user *, uaddr2, +@@ -3845,7 +4114,8 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, + + if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI || + cmd == FUTEX_WAIT_BITSET || +- cmd == FUTEX_WAIT_REQUEUE_PI)) { ++ cmd == FUTEX_WAIT_REQUEUE_PI || ++ cmd == FUTEX_WAIT_MULTIPLE)) { + if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG)))) + return -EFAULT; + if (get_timespec64(&ts, utime)) +@@ -3854,7 +4124,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, + return -EINVAL; + + t = timespec64_to_ktime(ts); +- if (cmd == FUTEX_WAIT) ++ if (cmd == FUTEX_WAIT || cmd == FUTEX_WAIT_MULTIPLE) + t = ktime_add_safe(ktime_get(), t); + tp = &t; + } +@@ -3866,6 +4136,25 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, + cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP) + val2 = (u32) (unsigned long) utime; + ++ if (cmd == FUTEX_WAIT_MULTIPLE) { ++ int ret; ++ struct futex_q *qs; ++ ++#ifdef CONFIG_X86_X32 ++ if (unlikely(in_x32_syscall())) ++ return -ENOSYS; ++#endif ++ qs = futex_read_wait_block(uaddr, val); ++ ++ if (IS_ERR(qs)) ++ return PTR_ERR(qs); ++ ++ ret = futex_wait_multiple(qs, op, val, tp); ++ kfree(qs); ++ ++ return ret; ++ } ++ + return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); + } + +@@ -4028,6 +4317,58 @@ COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid, + #endif /* CONFIG_COMPAT */ + + #ifdef CONFIG_COMPAT_32BIT_TIME ++/** ++ * struct compat_futex_wait_block - Block of futexes to be waited for ++ * @uaddr: User address of the futex (compatible pointer) ++ * @val: Futex value expected by userspace ++ * @bitset: Bitset for the optional bitmasked wakeup ++ */ ++struct compat_futex_wait_block { ++ compat_uptr_t uaddr; ++ __u32 pad; ++ __u32 val; ++ __u32 bitset; ++}; ++ ++/** ++ * compat_futex_read_wait_block - Read an array of futex_wait_block from ++ * userspace ++ * @uaddr: Userspace address of the block ++ * @count: Number of blocks to be read ++ * ++ * This function does the same as futex_read_wait_block(), except that it ++ * converts the pointer to the futex from the compat version to the regular one. ++ */ ++inline struct futex_q *compat_futex_read_wait_block(u32 __user *uaddr, ++ u32 count) ++{ ++ unsigned int i; ++ struct futex_q *qs; ++ struct compat_futex_wait_block fwb; ++ struct compat_futex_wait_block __user *entry = ++ (struct compat_futex_wait_block __user *)uaddr; ++ ++ if (!count || count > FUTEX_MULTIPLE_MAX_COUNT) ++ return ERR_PTR(-EINVAL); ++ ++ qs = kcalloc(count, sizeof(*qs), GFP_KERNEL); ++ if (!qs) ++ return ERR_PTR(-ENOMEM); ++ ++ for (i = 0; i < count; i++) { ++ if (copy_from_user(&fwb, &entry[i], sizeof(fwb))) { ++ kfree(qs); ++ return ERR_PTR(-EFAULT); ++ } ++ ++ qs[i].uaddr = compat_ptr(fwb.uaddr); ++ qs[i].uval = fwb.val; ++ qs[i].bitset = fwb.bitset; ++ } ++ ++ return qs; ++} ++ + SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val, + struct old_timespec32 __user *, utime, u32 __user *, uaddr2, + u32, val3) +@@ -4039,14 +4380,15 @@ SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val, + + if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI || + cmd == FUTEX_WAIT_BITSET || +- cmd == FUTEX_WAIT_REQUEUE_PI)) { ++ cmd == FUTEX_WAIT_REQUEUE_PI || ++ cmd == FUTEX_WAIT_MULTIPLE)) { + if (get_old_timespec32(&ts, utime)) + return -EFAULT; + if (!timespec64_valid(&ts)) + return -EINVAL; + + t = timespec64_to_ktime(ts); +- if (cmd == FUTEX_WAIT) ++ if (cmd == FUTEX_WAIT || cmd == FUTEX_WAIT_MULTIPLE) + t = ktime_add_safe(ktime_get(), t); + tp = &t; + } +@@ -4054,6 +4396,19 @@ SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val, + cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP) + val2 = (int) (unsigned long) utime; + ++ if (cmd == FUTEX_WAIT_MULTIPLE) { ++ int ret; ++ struct futex_q *qs = compat_futex_read_wait_block(uaddr, val); ++ ++ if (IS_ERR(qs)) ++ return PTR_ERR(qs); ++ ++ ret = futex_wait_multiple(qs, op, val, tp); ++ kfree(qs); ++ ++ return ret; ++ } ++ + return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); + } + #endif /* CONFIG_COMPAT_32BIT_TIME */ +-- +2.27.0.rc2 + + +From 3b2db8473486da199622782b28a9de69c4446323 Mon Sep 17 00:00:00 2001 +From: Gabriel Krisman Bertazi <krisman@collabora.com> +Date: Thu, 13 Feb 2020 18:45:23 -0300 +Subject: [PATCH 2/4] selftests: futex: Add FUTEX_WAIT_MULTIPLE timeout test +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Add test for timeout when waiting for multiple futexes. Skip the test if +it's a x32 application and the kernel returned the approtiaded error, +since this ABI is not supported for this operation. + +Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> +Co-developed-by: André Almeida <andrealmeid@collabora.com> +Signed-off-by: André Almeida <andrealmeid@collabora.com> +--- + .../futex/functional/futex_wait_timeout.c | 38 ++++++++++++++++++- + .../selftests/futex/include/futextest.h | 22 +++++++++++ + 2 files changed, 58 insertions(+), 2 deletions(-) + +diff --git a/tools/testing/selftests/futex/functional/futex_wait_timeout.c b/tools/testing/selftests/futex/functional/futex_wait_timeout.c +index ee55e6d38..2a63e1c2c 100644 +--- a/tools/testing/selftests/futex/functional/futex_wait_timeout.c ++++ b/tools/testing/selftests/futex/functional/futex_wait_timeout.c +@@ -11,6 +11,7 @@ + * + * HISTORY + * 2009-Nov-6: Initial version by Darren Hart <dvhart@linux.intel.com> ++ * 2019-Dec-13: Add WAIT_MULTIPLE test by Krisman <krisman@collabora.com> + * + *****************************************************************************/ + +@@ -41,6 +42,8 @@ int main(int argc, char *argv[]) + { + futex_t f1 = FUTEX_INITIALIZER; + struct timespec to; ++ time_t secs; ++ struct futex_wait_block fwb = {&f1, f1, 0}; + int res, ret = RET_PASS; + int c; + +@@ -65,7 +68,7 @@ int main(int argc, char *argv[]) + } + + ksft_print_header(); +- ksft_set_plan(1); ++ ksft_set_plan(2); + ksft_print_msg("%s: Block on a futex and wait for timeout\n", + basename(argv[0])); + ksft_print_msg("\tArguments: timeout=%ldns\n", timeout_ns); +@@ -79,8 +82,39 @@ int main(int argc, char *argv[]) + if (!res || errno != ETIMEDOUT) { + fail("futex_wait returned %d\n", ret < 0 ? errno : ret); + ret = RET_FAIL; ++ } else ++ ksft_test_result_pass("futex_wait timeout succeeds\n"); ++ ++ info("Calling futex_wait_multiple on f1: %u @ %p\n", f1, &f1); ++ ++ /* Setup absolute time */ ++ ret = clock_gettime(CLOCK_REALTIME, &to); ++ secs = (to.tv_nsec + timeout_ns) / 1000000000; ++ to.tv_nsec = ((int64_t)to.tv_nsec + timeout_ns) % 1000000000; ++ to.tv_sec += secs; ++ info("to.tv_sec = %ld\n", to.tv_sec); ++ info("to.tv_nsec = %ld\n", to.tv_nsec); ++ ++ res = futex_wait_multiple(&fwb, 1, &to, ++ FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME); ++ ++#ifdef __ILP32__ ++ if (res == -1 && errno == ENOSYS) { ++ ksft_test_result_skip("futex_wait_multiple not supported at x32\n"); ++ } else { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; + } ++#else ++ if (!res || errno != ETIMEDOUT) { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; ++ } else ++ ksft_test_result_pass("futex_wait_multiple timeout succeeds\n"); ++#endif /* __ILP32__ */ + +- print_result(TEST_NAME, ret); ++ ksft_print_cnts(); + return ret; + } +diff --git a/tools/testing/selftests/futex/include/futextest.h b/tools/testing/selftests/futex/include/futextest.h +index ddbcfc9b7..bb103bef4 100644 +--- a/tools/testing/selftests/futex/include/futextest.h ++++ b/tools/testing/selftests/futex/include/futextest.h +@@ -38,6 +38,14 @@ typedef volatile u_int32_t futex_t; + #ifndef FUTEX_CMP_REQUEUE_PI + #define FUTEX_CMP_REQUEUE_PI 12 + #endif ++#ifndef FUTEX_WAIT_MULTIPLE ++#define FUTEX_WAIT_MULTIPLE 13 ++struct futex_wait_block { ++ futex_t *uaddr; ++ futex_t val; ++ __u32 bitset; ++}; ++#endif + #ifndef FUTEX_WAIT_REQUEUE_PI_PRIVATE + #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \ + FUTEX_PRIVATE_FLAG) +@@ -80,6 +88,20 @@ futex_wait(futex_t *uaddr, futex_t val, struct timespec *timeout, int opflags) + return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); + } + ++/** ++ * futex_wait_multiple() - block on several futexes with optional timeout ++ * @fwb: wait block user space address ++ * @count: number of entities at fwb ++ * @timeout: absolute timeout ++ */ ++static inline int ++futex_wait_multiple(struct futex_wait_block *fwb, int count, ++ struct timespec *timeout, int opflags) ++{ ++ return futex(fwb, FUTEX_WAIT_MULTIPLE, count, timeout, NULL, 0, ++ opflags); ++} ++ + /** + * futex_wake() - wake one or more tasks blocked on uaddr + * @nr_wake: wake up to this many tasks +-- +2.27.0.rc2 + + +From b285216bc7b31eeba9b0e8081fe312bac7514931 Mon Sep 17 00:00:00 2001 +From: Gabriel Krisman Bertazi <krisman@collabora.com> +Date: Thu, 13 Feb 2020 18:45:24 -0300 +Subject: [PATCH 3/4] selftests: futex: Add FUTEX_WAIT_MULTIPLE wouldblock test +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Add test for wouldblock return when waiting for multiple futexes. Skip +the test if it's a x32 application and the kernel returned the approtiaded +error, since this ABI is not supported for this operation. + +Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> +Co-developed-by: André Almeida <andrealmeid@collabora.com> +Signed-off-by: André Almeida <andrealmeid@collabora.com> +--- + .../futex/functional/futex_wait_wouldblock.c | 28 +++++++++++++++++-- + 1 file changed, 26 insertions(+), 2 deletions(-) + +diff --git a/tools/testing/selftests/futex/functional/futex_wait_wouldblock.c b/tools/testing/selftests/futex/functional/futex_wait_wouldblock.c +index 0ae390ff8..bcbac0429 100644 +--- a/tools/testing/selftests/futex/functional/futex_wait_wouldblock.c ++++ b/tools/testing/selftests/futex/functional/futex_wait_wouldblock.c +@@ -12,6 +12,7 @@ + * + * HISTORY + * 2009-Nov-14: Initial version by Gowrishankar <gowrishankar.m@in.ibm.com> ++ * 2019-Dec-13: Add WAIT_MULTIPLE test by Krisman <krisman@collabora.com> + * + *****************************************************************************/ + +@@ -40,6 +41,7 @@ int main(int argc, char *argv[]) + { + struct timespec to = {.tv_sec = 0, .tv_nsec = timeout_ns}; + futex_t f1 = FUTEX_INITIALIZER; ++ struct futex_wait_block fwb = {&f1, f1+1, 0}; + int res, ret = RET_PASS; + int c; + +@@ -61,7 +63,7 @@ int main(int argc, char *argv[]) + } + + ksft_print_header(); +- ksft_set_plan(1); ++ ksft_set_plan(2); + ksft_print_msg("%s: Test the unexpected futex value in FUTEX_WAIT\n", + basename(argv[0])); + +@@ -71,8 +73,30 @@ int main(int argc, char *argv[]) + fail("futex_wait returned: %d %s\n", + res ? errno : res, res ? strerror(errno) : ""); + ret = RET_FAIL; ++ } else ++ ksft_test_result_pass("futex_wait wouldblock succeeds\n"); ++ ++ info("Calling futex_wait_multiple on f1: %u @ %p with val=%u\n", ++ f1, &f1, f1+1); ++ res = futex_wait_multiple(&fwb, 1, NULL, FUTEX_PRIVATE_FLAG); ++ ++#ifdef __ILP32__ ++ if (res != -1 || errno != ENOSYS) { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; ++ } else { ++ ksft_test_result_skip("futex_wait_multiple not supported at x32\n"); ++ } ++#else ++ if (!res || errno != EWOULDBLOCK) { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; + } ++ ksft_test_result_pass("futex_wait_multiple wouldblock succeeds\n"); ++#endif /* __ILP32__ */ + +- print_result(TEST_NAME, ret); ++ ksft_print_cnts(); + return ret; + } +-- +2.27.0.rc2 + + +From c2a6902699480877846a07e7567fbce94b370cce Mon Sep 17 00:00:00 2001 +From: Gabriel Krisman Bertazi <krisman@collabora.com> +Date: Thu, 13 Feb 2020 18:45:25 -0300 +Subject: [PATCH 4/4] selftests: futex: Add FUTEX_WAIT_MULTIPLE wake up test +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Add test for wait at multiple futexes mechanism. Skip the test if it's a +x32 application and the kernel returned the approtiaded error, since this +ABI is not supported for this operation. + +Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> +Co-developed-by: André Almeida <andrealmeid@collabora.com> +Signed-off-by: André Almeida <andrealmeid@collabora.com> +--- + .../selftests/futex/functional/.gitignore | 1 + + .../selftests/futex/functional/Makefile | 3 +- + .../futex/functional/futex_wait_multiple.c | 173 ++++++++++++++++++ + .../testing/selftests/futex/functional/run.sh | 3 + + 4 files changed, 179 insertions(+), 1 deletion(-) + create mode 100644 tools/testing/selftests/futex/functional/futex_wait_multiple.c + +diff --git a/tools/testing/selftests/futex/functional/.gitignore b/tools/testing/selftests/futex/functional/.gitignore +index 0efcd494d..03a4bedce 100644 +--- a/tools/testing/selftests/futex/functional/.gitignore ++++ b/tools/testing/selftests/futex/functional/.gitignore +@@ -6,3 +6,4 @@ futex_wait_private_mapped_file + futex_wait_timeout + futex_wait_uninitialized_heap + futex_wait_wouldblock ++futex_wait_multiple +diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile +index 23207829e..26562f2d7 100644 +--- a/tools/testing/selftests/futex/functional/Makefile ++++ b/tools/testing/selftests/futex/functional/Makefile +@@ -14,7 +14,8 @@ TEST_GEN_FILES := \ + futex_requeue_pi_signal_restart \ + futex_requeue_pi_mismatched_ops \ + futex_wait_uninitialized_heap \ +- futex_wait_private_mapped_file ++ futex_wait_private_mapped_file \ ++ futex_wait_multiple + + TEST_PROGS := run.sh + +diff --git a/tools/testing/selftests/futex/functional/futex_wait_multiple.c b/tools/testing/selftests/futex/functional/futex_wait_multiple.c +new file mode 100644 +index 000000000..b48422e79 +--- /dev/null ++++ b/tools/testing/selftests/futex/functional/futex_wait_multiple.c +@@ -0,0 +1,173 @@ ++// SPDX-License-Identifier: GPL-2.0-or-later ++/****************************************************************************** ++ * ++ * Copyright © Collabora, Ltd., 2019 ++ * ++ * DESCRIPTION ++ * Test basic semantics of FUTEX_WAIT_MULTIPLE ++ * ++ * AUTHOR ++ * Gabriel Krisman Bertazi <krisman@collabora.com> ++ * ++ * HISTORY ++ * 2019-Dec-13: Initial version by Krisman <krisman@collabora.com> ++ * ++ *****************************************************************************/ ++ ++#include <errno.h> ++#include <getopt.h> ++#include <stdio.h> ++#include <stdlib.h> ++#include <string.h> ++#include <time.h> ++#include <pthread.h> ++#include "futextest.h" ++#include "logging.h" ++ ++#define TEST_NAME "futex-wait-multiple" ++#define timeout_ns 100000 ++#define MAX_COUNT 128 ++#define WAKE_WAIT_US 3000000 ++ ++int ret = RET_PASS; ++char *progname; ++futex_t f[MAX_COUNT] = {0}; ++struct futex_wait_block fwb[MAX_COUNT]; ++ ++void usage(char *prog) ++{ ++ printf("Usage: %s\n", prog); ++ printf(" -c Use color\n"); ++ printf(" -h Display this help message\n"); ++ printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n", ++ VQUIET, VCRITICAL, VINFO); ++} ++ ++void test_count_overflow(void) ++{ ++ futex_t f = FUTEX_INITIALIZER; ++ struct futex_wait_block fwb[MAX_COUNT+1]; ++ int res, i; ++ ++ ksft_print_msg("%s: Test a too big number of futexes\n", progname); ++ ++ for (i = 0; i < MAX_COUNT+1; i++) { ++ fwb[i].uaddr = &f; ++ fwb[i].val = f; ++ fwb[i].bitset = 0; ++ } ++ ++ res = futex_wait_multiple(fwb, MAX_COUNT+1, NULL, FUTEX_PRIVATE_FLAG); ++ ++#ifdef __ILP32__ ++ if (res != -1 || errno != ENOSYS) { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; ++ } else { ++ ksft_test_result_skip("futex_wait_multiple not supported at x32\n"); ++ } ++#else ++ if (res != -1 || errno != EINVAL) { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; ++ } else { ++ ksft_test_result_pass("futex_wait_multiple count overflow succeed\n"); ++ } ++ ++#endif /* __ILP32__ */ ++} ++ ++void *waiterfn(void *arg) ++{ ++ int res; ++ ++ res = futex_wait_multiple(fwb, MAX_COUNT, NULL, FUTEX_PRIVATE_FLAG); ++ ++#ifdef __ILP32__ ++ if (res != -1 || errno != ENOSYS) { ++ ksft_test_result_fail("futex_wait_multiple returned %d\n", ++ res < 0 ? errno : res); ++ ret = RET_FAIL; ++ } else { ++ ksft_test_result_skip("futex_wait_multiple not supported at x32\n"); ++ } ++#else ++ if (res < 0) ++ ksft_print_msg("waiter failed %d\n", res); ++ ++ info("futex_wait_multiple: Got hint futex %d was freed\n", res); ++#endif /* __ILP32__ */ ++ ++ return NULL; ++} ++ ++void test_fwb_wakeup(void) ++{ ++ int res, i; ++ pthread_t waiter; ++ ++ ksft_print_msg("%s: Test wake up in a list of futex\n", progname); ++ ++ for (i = 0; i < MAX_COUNT; i++) { ++ fwb[i].uaddr = &f[i]; ++ fwb[i].val = f[i]; ++ fwb[i].bitset = 0xffffffff; ++ } ++ ++ res = pthread_create(&waiter, NULL, waiterfn, NULL); ++ if (res) { ++ ksft_test_result_fail("Creating waiting thread failed"); ++ ksft_exit_fail(); ++ } ++ ++ usleep(WAKE_WAIT_US); ++ res = futex_wake(&(f[MAX_COUNT-1]), 1, FUTEX_PRIVATE_FLAG); ++ if (res != 1) { ++ ksft_test_result_fail("Failed to wake thread res=%d\n", res); ++ ksft_exit_fail(); ++ } ++ ++ pthread_join(waiter, NULL); ++ ksft_test_result_pass("%s succeed\n", __func__); ++} ++ ++int main(int argc, char *argv[]) ++{ ++ int c; ++ ++ while ((c = getopt(argc, argv, "cht:v:")) != -1) { ++ switch (c) { ++ case 'c': ++ log_color(1); ++ break; ++ case 'h': ++ usage(basename(argv[0])); ++ exit(0); ++ case 'v': ++ log_verbosity(atoi(optarg)); ++ break; ++ default: ++ usage(basename(argv[0])); ++ exit(1); ++ } ++ } ++ ++ progname = basename(argv[0]); ++ ++ ksft_print_header(); ++ ksft_set_plan(2); ++ ++ test_count_overflow(); ++ ++#ifdef __ILP32__ ++ // if it's a 32x binary, there's no futex to wakeup ++ ksft_test_result_skip("futex_wait_multiple not supported at x32\n"); ++#else ++ test_fwb_wakeup(); ++#endif /* __ILP32__ */ ++ ++ ksft_print_cnts(); ++ return ret; ++} +diff --git a/tools/testing/selftests/futex/functional/run.sh b/tools/testing/selftests/futex/functional/run.sh +index 1acb6ace1..a8be94f28 100755 +--- a/tools/testing/selftests/futex/functional/run.sh ++++ b/tools/testing/selftests/futex/functional/run.sh +@@ -73,3 +73,6 @@ echo + echo + ./futex_wait_uninitialized_heap $COLOR + ./futex_wait_private_mapped_file $COLOR ++ ++echo ++./futex_wait_multiple $COLOR +-- +2.27.0.rc2 + |