On Wednesday, 14 February 2024 19:57:23 CST Randy Dunlap wrote:

Hi,

On 2/14/24 15:36, Elizabeth Figura wrote:

...

ntsync uses a misc device as the simplest and least intrusive uAPI interface.

Each file description on the device represents an isolated NT instance, intended to correspond to a single NT virtual machine.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com

drivers/misc/Kconfig | 9 ++++++++ drivers/misc/Makefile | 1 + drivers/misc/ntsync.c | 52 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 62 insertions(+) create mode 100644 drivers/misc/ntsync.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 4fb291f0bf7c..bdd8a71bd853 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -504,6 +504,15 @@ config OPEN_DICE measured boot flow. Userspace can use CDIs for remote attestation and sealing. +config NTSYNC

• tristate "NT synchronization primitive emulation"
• help

•  This module provides kernel support for emulation of Windows NT
  

•  synchronization primitives. It is not a hardware driver.
  

•  To compile this driver as a module, choose M here: the
  

•  module will be called ntsync.
  

• If unsure, say N.

It looks like the "If unsure" line belongs to the OPEN_DICE kconfig entry above here. If you want one for NTSYNC, please add one.

Oops, looks like that was a bad rebase :-(

...

config VCPU_STALL_DETECTOR

...

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c new file mode 100644 index 000000000000..e4969ef90722 --- /dev/null +++ b/drivers/misc/ntsync.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0-only +/*

• • ntsync.c - Kernel driver for NT synchronization primitives
• • Copyright (C) 2024 Elizabeth Figura

It would be nice to have your email address above...

...

• */

...

+MODULE_AUTHOR("Elizabeth Figura");

but at least please add it in MODULE_AUTHOR(). Yes it's optional, but roughly 7900 of 10400 entries do include it (according to my rough grepping).

Yes, I know that it's in MAINTAINERS.

Will add, thanks. As you guessed I did just pick an arbitrary module to copy.

On Wed, Feb 14, 2024 at 05:36:38PM -0600, Elizabeth Figura wrote:

This corresponds to the NT syscall NtCreateSemaphore().

Semaphores are one of three types of object to be implemented in this driver, the others being mutexes and events.

An NT semaphore contains a 32-bit counter, and is signaled and can be acquired when the counter is nonzero. The counter has a maximum value which is specified at creation time. The initial value of the semaphore is also specified at creation time. There are no restrictions on the maximum and initial value.

Each object is exposed as an file, to which any number of fds may be opened. When all fds are closed, the object is deleted.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com

.../userspace-api/ioctl/ioctl-number.rst | 2 + drivers/misc/ntsync.c | 120 ++++++++++++++++++ include/uapi/linux/ntsync.h | 21 +++ 3 files changed, 143 insertions(+) create mode 100644 include/uapi/linux/ntsync.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 457e16f06e04..2f5c6994f042 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -173,6 +173,8 @@ Code Seq# Include File Comments 'M' 00-0F drivers/video/fsl-diu-fb.h conflict! 'N' 00-1F drivers/usb/scanner.h 'N' 40-7F drivers/block/nvme.c +'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives

•                                                                 <mailto:wine-devel@winehq.org>
  

'O' 00-06 mtd/ubi-user.h UBI 'P' all linux/soundcard.h conflict! 'P' 60-6F sound/sscape_ioctl.h conflict! diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index e4969ef90722..3ad86d98b82d 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -5,26 +5,146 @@

• Copyright (C) 2024 Elizabeth Figura

*/ +#include <linux/anon_inodes.h> +#include <linux/file.h> #include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/module.h> +#include <linux/slab.h> +#include <uapi/linux/ntsync.h> #define NTSYNC_NAME "ntsync" +enum ntsync_type {

• NTSYNC_TYPE_SEM,

+};

+struct ntsync_obj {

• enum ntsync_type type;
• union {

• struct {
  

• 	__u32 count;
  

• 	__u32 max;
  

• } sem;
  

• } u;
• struct file *file;
• struct ntsync_device *dev;

+};

+struct ntsync_device {

• struct file *file;

+};

No reference counting is needed for your ntsync_device? Or are you relying on the reference counting of struct file here?

You pass around pointers to this structure, and save it off into other structures, how do you know it is "safe" to do so?

thanks,

greg k-h

On Thu, Feb 15, 2024 at 01:22:01PM -0600, Elizabeth Figura wrote:

On Thursday, 15 February 2024 01:28:32 CST Greg Kroah-Hartman wrote:

...

On Wed, Feb 14, 2024 at 05:36:38PM -0600, Elizabeth Figura wrote:

...

This corresponds to the NT syscall NtCreateSemaphore().

Semaphores are one of three types of object to be implemented in this driver, the others being mutexes and events.

An NT semaphore contains a 32-bit counter, and is signaled and can be acquired when the counter is nonzero. The counter has a maximum value which is specified at creation time. The initial value of the semaphore is also specified at creation time. There are no restrictions on the maximum and initial value.

Each object is exposed as an file, to which any number of fds may be opened. When all fds are closed, the object is deleted.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com

.../userspace-api/ioctl/ioctl-number.rst | 2 + drivers/misc/ntsync.c | 120 ++++++++++++++++++ include/uapi/linux/ntsync.h | 21 +++ 3 files changed, 143 insertions(+) create mode 100644 include/uapi/linux/ntsync.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 457e16f06e04..2f5c6994f042 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -173,6 +173,8 @@ Code Seq# Include File Comments 'M' 00-0F drivers/video/fsl-diu-fb.h conflict! 'N' 00-1F drivers/usb/scanner.h 'N' 40-7F drivers/block/nvme.c +'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives

•                                                                 <mailto:wine-devel@winehq.org>
  

'O' 00-06 mtd/ubi-user.h UBI 'P' all linux/soundcard.h conflict! 'P' 60-6F sound/sscape_ioctl.h conflict! diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index e4969ef90722..3ad86d98b82d 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -5,26 +5,146 @@

• Copyright (C) 2024 Elizabeth Figura

*/ +#include <linux/anon_inodes.h> +#include <linux/file.h> #include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/module.h> +#include <linux/slab.h> +#include <uapi/linux/ntsync.h> #define NTSYNC_NAME "ntsync" +enum ntsync_type {

• NTSYNC_TYPE_SEM,

+};

+struct ntsync_obj {

• enum ntsync_type type;
• union {

• struct {
  

• 	__u32 count;
  

• 	__u32 max;
  

• } sem;
  

• } u;
• struct file *file;
• struct ntsync_device *dev;

+};

+struct ntsync_device {

• struct file *file;

+};

No reference counting is needed for your ntsync_device? Or are you relying on the reference counting of struct file here?

You pass around pointers to this structure, and save it off into other structures, how do you know it is "safe" to do so?

Yes, this relies on the reference counting of struct file. The sync objects (semaphore etc.) grab a reference when they're created, via get_file(), and release it when they're destroyed. This reference is taken from within ioctls on the ntsync_device, so the file must be valid when we grab a reference. Maybe I'm missing something, though?

If the reference count is driven by struct file, that's fine, and great, otherwise you end up with two different reference counts and keeping them in sync is impossible.

But as it wasn't obvious, a comment somewhere here would be helpful for reviewing and figuring out how this all works in 4 years when someone has to touch it again.

thanks,

greg k-h

This corresponds to the NT syscall NtResetEvent().

This sets the event to the unsignaled state, and returns its previous state.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- drivers/misc/ntsync.c | 22 ++++++++++++++++++++++ include/uapi/linux/ntsync.h | 1 + 2 files changed, 23 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index bc24de02fd1c..57d78b086241 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -491,6 +491,26 @@ static int ntsync_event_set(struct ntsync_obj *event, void __user *argp) return 0; }

+static int ntsync_event_reset(struct ntsync_obj *event, void __user *argp) +{ + __u32 prev_state; + + if (event->type != NTSYNC_TYPE_EVENT) + return -EINVAL; + + spin_lock(&event->lock); + + prev_state = event->u.event.signaled; + event->u.event.signaled = false; + + spin_unlock(&event->lock); + + if (put_user(prev_state, (__u32 __user *)argp)) + return -EFAULT; + + return 0; +} + static int ntsync_obj_release(struct inode *inode, struct file *file) { struct ntsync_obj *obj = file->private_data; @@ -516,6 +536,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd, return ntsync_mutex_kill(obj, argp); case NTSYNC_IOC_EVENT_SET: return ntsync_event_set(obj, argp); + case NTSYNC_IOC_EVENT_RESET: + return ntsync_event_reset(obj, argp); default: return -ENOIOCTLCMD; } diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 782057552483..f2d7507d8438 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -49,5 +49,6 @@ struct ntsync_wait_args { #define NTSYNC_IOC_MUTEX_UNLOCK _IOWR('N', 0x85, struct ntsync_mutex_args) #define NTSYNC_IOC_MUTEX_KILL _IOW ('N', 0x86, __u32) #define NTSYNC_IOC_EVENT_SET _IOR ('N', 0x88, __u32) +#define NTSYNC_IOC_EVENT_RESET _IOR ('N', 0x89, __u32)

#endif

This corresponds to the NT syscall NtQuerySemaphore().

This returns the current count and maximum count of the semaphore.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- drivers/misc/ntsync.c | 21 +++++++++++++++++++++ include/uapi/linux/ntsync.h | 1 + 2 files changed, 22 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index e8e58274e4e8..e42dbd5d6d14 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -515,6 +515,25 @@ static int ntsync_event_reset(struct ntsync_obj *event, void __user *argp) return 0; }

+static int ntsync_sem_read(struct ntsync_obj *sem, void __user *argp) +{ + struct ntsync_sem_args __user *user_args = argp; + struct ntsync_sem_args args; + + if (sem->type != NTSYNC_TYPE_SEM) + return -EINVAL; + + args.sem = 0; + spin_lock(&sem->lock); + args.count = sem->u.sem.count; + args.max = sem->u.sem.max; + spin_unlock(&sem->lock); + + if (copy_to_user(user_args, &args, sizeof(args))) + return -EFAULT; + return 0; +} + static int ntsync_obj_release(struct inode *inode, struct file *file) { struct ntsync_obj *obj = file->private_data; @@ -534,6 +553,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd, switch (cmd) { case NTSYNC_IOC_SEM_POST: return ntsync_sem_post(obj, argp); + case NTSYNC_IOC_SEM_READ: + return ntsync_sem_read(obj, argp); case NTSYNC_IOC_MUTEX_UNLOCK: return ntsync_mutex_unlock(obj, argp); case NTSYNC_IOC_MUTEX_KILL: diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 598f894f868d..6017f621687e 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -51,5 +51,6 @@ struct ntsync_wait_args { #define NTSYNC_IOC_EVENT_SET _IOR ('N', 0x88, __u32) #define NTSYNC_IOC_EVENT_RESET _IOR ('N', 0x89, __u32) #define NTSYNC_IOC_EVENT_PULSE _IOR ('N', 0x8a, __u32) +#define NTSYNC_IOC_SEM_READ _IOR ('N', 0x8b, struct ntsync_sem_args)

#endif

This corresponds to the NT syscall NtQueryEvent().

This returns the signaled state of the event and whether it is manual-reset.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- drivers/misc/ntsync.c | 21 +++++++++++++++++++++ include/uapi/linux/ntsync.h | 1 + 2 files changed, 22 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 73f40ea1c8f8..5bf7af8095e6 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -555,6 +555,25 @@ static int ntsync_mutex_read(struct ntsync_obj *mutex, void __user *argp) return ret; }

+static int ntsync_event_read(struct ntsync_obj *event, void __user *argp) +{ + struct ntsync_event_args __user *user_args = argp; + struct ntsync_event_args args; + + if (event->type != NTSYNC_TYPE_EVENT) + return -EINVAL; + + args.event = 0; + spin_lock(&event->lock); + args.manual = event->u.event.manual; + args.signaled = event->u.event.signaled; + spin_unlock(&event->lock); + + if (copy_to_user(user_args, &args, sizeof(args))) + return -EFAULT; + return 0; +} + static int ntsync_obj_release(struct inode *inode, struct file *file) { struct ntsync_obj *obj = file->private_data; @@ -588,6 +607,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd, return ntsync_event_reset(obj, argp); case NTSYNC_IOC_EVENT_PULSE: return ntsync_event_set(obj, argp, true); + case NTSYNC_IOC_EVENT_READ: + return ntsync_event_read(obj, argp); default: return -ENOIOCTLCMD; } diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index a1d0ef581212..582d33b0dcac 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -53,5 +53,6 @@ struct ntsync_wait_args { #define NTSYNC_IOC_EVENT_PULSE _IOR ('N', 0x8a, __u32) #define NTSYNC_IOC_SEM_READ _IOR ('N', 0x8b, struct ntsync_sem_args) #define NTSYNC_IOC_MUTEX_READ _IOR ('N', 0x8c, struct ntsync_mutex_args) +#define NTSYNC_IOC_EVENT_READ _IOR ('N', 0x8d, struct ntsync_event_args)

#endif

NtWaitForMultipleObjects() can receive a timeout in two forms, relative or absolute. Relative timeouts are unaffected by changes to the system time and do not count down while the system suspends; for absolute timeouts the opposite is true.

In order to make the interface and implementation simpler, the ntsync driver only deals in absolute timeouts. However, we need to be able to emulate both behaviours apropos suspension and time adjustment, which is achieved by allowing either the MONOTONIC or REALTIME clock to be used.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- drivers/misc/ntsync.c | 9 ++++++++- include/uapi/linux/ntsync.h | 4 ++++ 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c index 0773602cc86d..496704268603 100644 --- a/drivers/misc/ntsync.c +++ b/drivers/misc/ntsync.c @@ -765,11 +765,15 @@ static void put_obj(struct ntsync_obj *obj) static int ntsync_schedule(const struct ntsync_q *q, const struct ntsync_wait_args *args) { ktime_t timeout = ns_to_ktime(args->timeout); + clockid_t clock = CLOCK_MONOTONIC; ktime_t *timeout_ptr; int ret = 0;

timeout_ptr = (args->timeout == U64_MAX ? NULL : &timeout);

+ if (args->flags & NTSYNC_WAIT_REALTIME) + clock = CLOCK_REALTIME; + do { if (signal_pending(current)) { ret = -ERESTARTSYS; @@ -781,7 +785,7 @@ static int ntsync_schedule(const struct ntsync_q *q, const struct ntsync_wait_ar ret = 0; break; } - ret = schedule_hrtimeout(timeout_ptr, HRTIMER_MODE_ABS); + ret = schedule_hrtimeout_range_clock(timeout_ptr, 0, HRTIMER_MODE_ABS, clock); } while (ret < 0); __set_current_state(TASK_RUNNING);

@@ -804,6 +808,9 @@ static int setup_wait(struct ntsync_device *dev, if (!args->owner) return -EINVAL;

+ if (args->pad || (args->flags & ~NTSYNC_WAIT_REALTIME)) + return -EINVAL; + if (args->count > NTSYNC_MAX_WAIT_COUNT) return -EINVAL;

diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h index 7c91af7011e4..074f26423426 100644 --- a/include/uapi/linux/ntsync.h +++ b/include/uapi/linux/ntsync.h @@ -28,6 +28,8 @@ struct ntsync_event_args { __u32 signaled; };

+#define NTSYNC_WAIT_REALTIME 0x1 + struct ntsync_wait_args { __u64 timeout; __u64 objs; @@ -35,6 +37,8 @@ struct ntsync_wait_args { __u32 owner; __u32 index; __u32 alert; + __u32 flags; + __u32 pad; };

#define NTSYNC_MAX_WAIT_COUNT 64

Test mutex-specific ioctls NTSYNC_IOC_MUTEX_UNLOCK and NTSYNC_IOC_MUTEX_READ, and waiting on mutexes.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- .../testing/selftests/drivers/ntsync/ntsync.c | 196 ++++++++++++++++++ 1 file changed, 196 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index bda88233b427..d2c0c97839ba 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -40,6 +40,39 @@ static int post_sem(int sem, __u32 *count) return ioctl(sem, NTSYNC_IOC_SEM_POST, count); }

+static int read_mutex_state(int mutex, __u32 *count, __u32 *owner) +{ + struct ntsync_mutex_args args; + int ret; + + memset(&args, 0xcc, sizeof(args)); + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &args); + *count = args.count; + *owner = args.owner; + return ret; +} + +#define check_mutex_state(mutex, count, owner) \ + ({ \ + __u32 __count, __owner; \ + int ret = read_mutex_state((mutex), &__count, &__owner); \ + EXPECT_EQ(0, ret); \ + EXPECT_EQ((count), __count); \ + EXPECT_EQ((owner), __owner); \ + }) + +static int unlock_mutex(int mutex, __u32 owner, __u32 *count) +{ + struct ntsync_mutex_args args; + int ret; + + args.owner = owner; + args.count = 0xdeadbeef; + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_UNLOCK, &args); + *count = args.count; + return ret; +} + static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index) { struct ntsync_wait_args args = {0}; @@ -146,4 +179,167 @@ TEST(semaphore_state) close(fd); }

+TEST(mutex_state) +{ + struct ntsync_mutex_args mutex_args; + __u32 owner, count, index; + struct timespec timeout; + int fd, ret, mutex; + + clock_gettime(CLOCK_MONOTONIC, &timeout); + + fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, fd); + + mutex_args.owner = 123; + mutex_args.count = 0; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EINVAL, errno); + + mutex_args.owner = 0; + mutex_args.count = 2; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EINVAL, errno); + + mutex_args.owner = 123; + mutex_args.count = 2; + mutex_args.mutex = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, mutex_args.mutex); + mutex = mutex_args.mutex; + check_mutex_state(mutex, 2, 123); + + ret = unlock_mutex(mutex, 0, &count); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EINVAL, errno); + + ret = unlock_mutex(mutex, 456, &count); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EPERM, errno); + check_mutex_state(mutex, 2, 123); + + ret = unlock_mutex(mutex, 123, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(2, count); + check_mutex_state(mutex, 1, 123); + + ret = unlock_mutex(mutex, 123, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(1, count); + check_mutex_state(mutex, 0, 0); + + ret = unlock_mutex(mutex, 123, &count); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EPERM, errno); + + ret = wait_any(fd, 1, &mutex, 456, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_mutex_state(mutex, 1, 456); + + ret = wait_any(fd, 1, &mutex, 456, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_mutex_state(mutex, 2, 456); + + ret = unlock_mutex(mutex, 456, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(2, count); + check_mutex_state(mutex, 1, 456); + + ret = wait_any(fd, 1, &mutex, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + + owner = 0; + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EINVAL, errno); + + owner = 123; + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EPERM, errno); + check_mutex_state(mutex, 1, 456); + + owner = 456; + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner); + EXPECT_EQ(0, ret); + + memset(&mutex_args, 0xcc, sizeof(mutex_args)); + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &mutex_args); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EOWNERDEAD, errno); + EXPECT_EQ(0, mutex_args.count); + EXPECT_EQ(0, mutex_args.owner); + + memset(&mutex_args, 0xcc, sizeof(mutex_args)); + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &mutex_args); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EOWNERDEAD, errno); + EXPECT_EQ(0, mutex_args.count); + EXPECT_EQ(0, mutex_args.owner); + + ret = wait_any(fd, 1, &mutex, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EOWNERDEAD, errno); + EXPECT_EQ(0, index); + check_mutex_state(mutex, 1, 123); + + owner = 123; + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_KILL, &owner); + EXPECT_EQ(0, ret); + + memset(&mutex_args, 0xcc, sizeof(mutex_args)); + ret = ioctl(mutex, NTSYNC_IOC_MUTEX_READ, &mutex_args); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EOWNERDEAD, errno); + EXPECT_EQ(0, mutex_args.count); + EXPECT_EQ(0, mutex_args.owner); + + ret = wait_any(fd, 1, &mutex, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EOWNERDEAD, errno); + EXPECT_EQ(0, index); + check_mutex_state(mutex, 1, 123); + + close(mutex); + + mutex_args.owner = 0; + mutex_args.count = 0; + mutex_args.mutex = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, mutex_args.mutex); + mutex = mutex_args.mutex; + check_mutex_state(mutex, 0, 0); + + ret = wait_any(fd, 1, &mutex, 123, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_mutex_state(mutex, 1, 123); + + close(mutex); + + mutex_args.owner = 123; + mutex_args.count = ~0u; + mutex_args.mutex = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, mutex_args.mutex); + mutex = mutex_args.mutex; + check_mutex_state(mutex, ~0u, 123); + + ret = wait_any(fd, 1, &mutex, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + + close(mutex); + + close(fd); +} + TEST_HARNESS_MAIN

Test basic synchronous functionality of NTSYNC_IOC_WAIT_ALL, and when objects are considered simultaneously signaled.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- .../testing/selftests/drivers/ntsync/ntsync.c | 99 ++++++++++++++++++- 1 file changed, 97 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index ca61fb17439b..6bb3bdc2ef3c 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -73,7 +73,8 @@ static int unlock_mutex(int mutex, __u32 owner, __u32 *count) return ret; }

-static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index) +static int wait_objs(int fd, unsigned long request, __u32 count, + const int *objs, __u32 owner, __u32 *index) { struct ntsync_wait_args args = {0}; struct timespec timeout; @@ -86,11 +87,21 @@ static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *in args.objs = (uintptr_t)objs; args.owner = owner; args.index = 0xdeadbeef; - ret = ioctl(fd, NTSYNC_IOC_WAIT_ANY, &args); + ret = ioctl(fd, request, &args); *index = args.index; return ret; }

+static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index) +{ + return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, count, objs, owner, index); +} + +static int wait_all(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index) +{ + return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, count, objs, owner, index); +} + TEST(semaphore_state) { struct ntsync_sem_args sem_args; @@ -461,4 +472,88 @@ TEST(test_wait_any) close(fd); }

+TEST(test_wait_all) +{ + struct ntsync_mutex_args mutex_args = {0}; + struct ntsync_sem_args sem_args = {0}; + __u32 owner, index, count; + int objs[2], fd, ret; + + fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, fd); + + sem_args.count = 2; + sem_args.max = 3; + sem_args.sem = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, sem_args.sem); + + mutex_args.owner = 0; + mutex_args.count = 0; + mutex_args.mutex = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, mutex_args.mutex); + + objs[0] = sem_args.sem; + objs[1] = mutex_args.mutex; + + ret = wait_all(fd, 2, objs, 123, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_sem_state(sem_args.sem, 1, 3); + check_mutex_state(mutex_args.mutex, 1, 123); + + ret = wait_all(fd, 2, objs, 456, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + check_sem_state(sem_args.sem, 1, 3); + check_mutex_state(mutex_args.mutex, 1, 123); + + ret = wait_all(fd, 2, objs, 123, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_sem_state(sem_args.sem, 0, 3); + check_mutex_state(mutex_args.mutex, 2, 123); + + ret = wait_all(fd, 2, objs, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + check_sem_state(sem_args.sem, 0, 3); + check_mutex_state(mutex_args.mutex, 2, 123); + + count = 3; + ret = post_sem(sem_args.sem, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, count); + + ret = wait_all(fd, 2, objs, 123, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_sem_state(sem_args.sem, 2, 3); + check_mutex_state(mutex_args.mutex, 3, 123); + + owner = 123; + ret = ioctl(mutex_args.mutex, NTSYNC_IOC_MUTEX_KILL, &owner); + EXPECT_EQ(0, ret); + + ret = wait_all(fd, 2, objs, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EOWNERDEAD, errno); + check_sem_state(sem_args.sem, 1, 3); + check_mutex_state(mutex_args.mutex, 1, 123); + + /* test waiting on the same object twice */ + objs[0] = objs[1] = sem_args.sem; + ret = wait_all(fd, 2, objs, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(EINVAL, errno); + + close(sem_args.sem); + close(mutex_args.mutex); + + close(fd); +} + TEST_HARNESS_MAIN

Test contended "wait-for-all" waits, to make sure that scheduling and wakeup logic works correctly, and that the wait only exits once objects are all simultaneously signaled.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- .../testing/selftests/drivers/ntsync/ntsync.c | 98 +++++++++++++++++++ 1 file changed, 98 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index e825e115f11f..063c0ecb3bff 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -706,4 +706,102 @@ TEST(wake_any) close(fd); }

+TEST(wake_all) +{ + struct ntsync_mutex_args mutex_args = {0}; + struct ntsync_wait_args wait_args = {0}; + struct ntsync_sem_args sem_args = {0}; + struct wait_args thread_args; + int objs[2], fd, ret; + __u32 count, index; + pthread_t thread; + + fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, fd); + + sem_args.count = 0; + sem_args.max = 3; + sem_args.sem = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, sem_args.sem); + + mutex_args.owner = 123; + mutex_args.count = 1; + mutex_args.mutex = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, mutex_args.mutex); + + objs[0] = sem_args.sem; + objs[1] = mutex_args.mutex; + + wait_args.timeout = get_abs_timeout(1000); + wait_args.objs = (uintptr_t)objs; + wait_args.count = 2; + wait_args.owner = 456; + thread_args.fd = fd; + thread_args.args = &wait_args; + thread_args.request = NTSYNC_IOC_WAIT_ALL; + ret = pthread_create(&thread, NULL, wait_thread, &thread_args); + EXPECT_EQ(0, ret); + + ret = wait_for_thread(thread, 100); + EXPECT_EQ(ETIMEDOUT, ret); + + count = 1; + ret = post_sem(sem_args.sem, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, count); + + ret = pthread_tryjoin_np(thread, NULL); + EXPECT_EQ(EBUSY, ret); + + check_sem_state(sem_args.sem, 1, 3); + + ret = wait_any(fd, 1, &sem_args.sem, 123, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + + ret = unlock_mutex(mutex_args.mutex, 123, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(1, count); + + ret = pthread_tryjoin_np(thread, NULL); + EXPECT_EQ(EBUSY, ret); + + check_mutex_state(mutex_args.mutex, 0, 0); + + count = 2; + ret = post_sem(sem_args.sem, &count); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, count); + check_sem_state(sem_args.sem, 1, 3); + check_mutex_state(mutex_args.mutex, 1, 456); + + ret = wait_for_thread(thread, 100); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, thread_args.ret); + + /* delete an object while it's being waited on */ + + wait_args.timeout = get_abs_timeout(200); + wait_args.owner = 123; + ret = pthread_create(&thread, NULL, wait_thread, &thread_args); + EXPECT_EQ(0, ret); + + ret = wait_for_thread(thread, 100); + EXPECT_EQ(ETIMEDOUT, ret); + + close(sem_args.sem); + close(mutex_args.mutex); + + ret = wait_for_thread(thread, 200); + EXPECT_EQ(0, ret); + EXPECT_EQ(-1, thread_args.ret); + EXPECT_EQ(ETIMEDOUT, thread_args.err); + + close(fd); +} + TEST_HARNESS_MAIN

Test event-specific ioctls NTSYNC_IOC_EVENT_SET, NTSYNC_IOC_EVENT_RESET, NTSYNC_IOC_EVENT_PULSE, NTSYNC_IOC_EVENT_READ for auto-reset events, and waiting on auto-reset events.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- .../testing/selftests/drivers/ntsync/ntsync.c | 59 +++++++++++++++++++ 1 file changed, 59 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index 7cc6fdf10abd..49ee4be280f6 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -442,6 +442,65 @@ TEST(manual_event_state) close(fd); }

+TEST(auto_event_state) +{ + struct ntsync_event_args event_args; + __u32 index, signaled; + int fd, event, ret; + + fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, fd); + + event_args.manual = 0; + event_args.signaled = 1; + event_args.event = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, event_args.event); + event = event_args.event; + + check_event_state(event, 1, 0); + + signaled = 0xdeadbeef; + ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled); + EXPECT_EQ(0, ret); + EXPECT_EQ(1, signaled); + check_event_state(event, 1, 0); + + ret = wait_any(fd, 1, &event, 123, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + check_event_state(event, 0, 0); + + signaled = 0xdeadbeef; + ret = ioctl(event, NTSYNC_IOC_EVENT_RESET, &signaled); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, signaled); + check_event_state(event, 0, 0); + + ret = wait_any(fd, 1, &event, 123, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + + ret = ioctl(event, NTSYNC_IOC_EVENT_SET, &signaled); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, signaled); + + ret = ioctl(event, NTSYNC_IOC_EVENT_PULSE, &signaled); + EXPECT_EQ(0, ret); + EXPECT_EQ(1, signaled); + check_event_state(event, 0, 0); + + ret = ioctl(event, NTSYNC_IOC_EVENT_PULSE, &signaled); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, signaled); + check_event_state(event, 0, 0); + + close(event); + + close(fd); +} + TEST(test_wait_any) { int objs[NTSYNC_MAX_WAIT_COUNT + 1], fd, ret;

Test the "alert" functionality of NTSYNC_IOC_WAIT_ALL and NTSYNC_IOC_WAIT_ANY, when a wait is woken with an alert and when it is woken by an object.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- .../testing/selftests/drivers/ntsync/ntsync.c | 179 +++++++++++++++++- 1 file changed, 176 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index bcf33bcf8c51..6c13b1f25d38 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -95,7 +95,7 @@ static int read_event_state(int event, __u32 *signaled, __u32 *manual) })

static int wait_objs(int fd, unsigned long request, __u32 count, - const int *objs, __u32 owner, __u32 *index) + const int *objs, __u32 owner, int alert, __u32 *index) { struct ntsync_wait_args args = {0}; struct timespec timeout; @@ -108,6 +108,7 @@ static int wait_objs(int fd, unsigned long request, __u32 count, args.objs = (uintptr_t)objs; args.owner = owner; args.index = 0xdeadbeef; + args.alert = alert; ret = ioctl(fd, request, &args); *index = args.index; return ret; @@ -115,12 +116,26 @@ static int wait_objs(int fd, unsigned long request, __u32 count,

static int wait_any(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index) { - return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, count, objs, owner, index); + return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, count, objs, owner, 0, index); }

static int wait_all(int fd, __u32 count, const int *objs, __u32 owner, __u32 *index) { - return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, count, objs, owner, index); + return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, count, objs, owner, 0, index); +} + +static int wait_any_alert(int fd, __u32 count, const int *objs, + __u32 owner, int alert, __u32 *index) +{ + return wait_objs(fd, NTSYNC_IOC_WAIT_ANY, + count, objs, owner, alert, index); +} + +static int wait_all_alert(int fd, __u32 count, const int *objs, + __u32 owner, int alert, __u32 *index) +{ + return wait_objs(fd, NTSYNC_IOC_WAIT_ALL, + count, objs, owner, alert, index); }

TEST(semaphore_state) @@ -1095,4 +1110,162 @@ TEST(wake_all) close(fd); }

+TEST(alert_any) +{ + struct ntsync_event_args event_args = {0}; + struct ntsync_sem_args sem_args = {0}; + __u32 index, count, signaled; + int objs[2], fd, ret; + + fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, fd); + + sem_args.count = 0; + sem_args.max = 2; + sem_args.sem = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, sem_args.sem); + objs[0] = sem_args.sem; + + sem_args.count = 1; + sem_args.max = 2; + sem_args.sem = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, sem_args.sem); + objs[1] = sem_args.sem; + + event_args.manual = true; + event_args.signaled = true; + ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args); + EXPECT_EQ(0, ret); + + ret = wait_any_alert(fd, 0, NULL, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + + ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_RESET, &signaled); + EXPECT_EQ(0, ret); + + ret = wait_any_alert(fd, 0, NULL, 123, event_args.event, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + + ret = ioctl(event_args.event, NTSYNC_IOC_EVENT_SET, &signaled); + EXPECT_EQ(0, ret); + + ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(1, index); + + ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(2, index); + + close(event_args.event); + + /* test with an auto-reset event */ + + event_args.manual = false; + event_args.signaled = true; + ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args); + EXPECT_EQ(0, ret); + + count = 1; + ret = post_sem(objs[0], &count); + EXPECT_EQ(0, ret); + + ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + + ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(2, index); + + ret = wait_any_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + + close(event_args.event); + + close(objs[0]); + close(objs[1]); + + close(fd); +} + +TEST(alert_all) +{ + struct ntsync_event_args event_args = {0}; + struct ntsync_sem_args sem_args = {0}; + __u32 index, count, signaled; + int objs[2], fd, ret; + + fd = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, fd); + + sem_args.count = 2; + sem_args.max = 2; + sem_args.sem = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, sem_args.sem); + objs[0] = sem_args.sem; + + sem_args.count = 1; + sem_args.max = 2; + sem_args.sem = 0xdeadbeef; + ret = ioctl(fd, NTSYNC_IOC_CREATE_SEM, &sem_args); + EXPECT_EQ(0, ret); + EXPECT_NE(0xdeadbeef, sem_args.sem); + objs[1] = sem_args.sem; + + event_args.manual = true; + event_args.signaled = true; + ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args); + EXPECT_EQ(0, ret); + + ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + + ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(2, index); + + close(event_args.event); + + /* test with an auto-reset event */ + + event_args.manual = false; + event_args.signaled = true; + ret = ioctl(fd, NTSYNC_IOC_CREATE_EVENT, &event_args); + EXPECT_EQ(0, ret); + + count = 2; + ret = post_sem(objs[1], &count); + EXPECT_EQ(0, ret); + + ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(0, index); + + ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(0, ret); + EXPECT_EQ(2, index); + + ret = wait_all_alert(fd, 2, objs, 123, event_args.event, &index); + EXPECT_EQ(-1, ret); + EXPECT_EQ(ETIMEDOUT, errno); + + close(event_args.event); + + close(objs[0]); + close(objs[1]); + + close(fd); +} + TEST_HARNESS_MAIN

Test a more realistic usage pattern, and one with heavy contention, in order to actually exercise ntsync's internal synchronization.

This test has several threads in a tight loop acquiring a mutex, modifying some shared data, and then releasing the mutex. At the end we check if the data is consistent.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- .../testing/selftests/drivers/ntsync/ntsync.c | 74 +++++++++++++++++++ 1 file changed, 74 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c index 40cfdd356ef4..aba513c9af01 100644 --- a/tools/testing/selftests/drivers/ntsync/ntsync.c +++ b/tools/testing/selftests/drivers/ntsync/ntsync.c @@ -1330,4 +1330,78 @@ TEST(alert_all) close(fd); }

+#define STRESS_LOOPS 10000 +#define STRESS_THREADS 4 + +static unsigned int stress_counter; +static int stress_device, stress_start_event, stress_mutex; + +static void *stress_thread(void *arg) +{ + struct ntsync_wait_args wait_args = {0}; + __u32 index, count, i; + int ret; + + wait_args.timeout = UINT64_MAX; + wait_args.count = 1; + wait_args.objs = (uintptr_t)&stress_start_event; + wait_args.owner = gettid(); + wait_args.index = 0xdeadbeef; + + ioctl(stress_device, NTSYNC_IOC_WAIT_ANY, &wait_args); + + wait_args.objs = (uintptr_t)&stress_mutex; + + for (i = 0; i < STRESS_LOOPS; ++i) { + ioctl(stress_device, NTSYNC_IOC_WAIT_ANY, &wait_args); + + ++stress_counter; + + unlock_mutex(stress_mutex, wait_args.owner, &count); + } + + return NULL; +} + +TEST(stress_wait) +{ + struct ntsync_event_args event_args; + struct ntsync_mutex_args mutex_args; + pthread_t threads[STRESS_THREADS]; + __u32 signaled, i; + int ret; + + stress_device = open("/dev/ntsync", O_CLOEXEC | O_RDONLY); + ASSERT_LE(0, stress_device); + + mutex_args.owner = 0; + mutex_args.count = 0; + ret = ioctl(stress_device, NTSYNC_IOC_CREATE_MUTEX, &mutex_args); + EXPECT_EQ(0, ret); + stress_mutex = mutex_args.mutex; + + event_args.manual = 1; + event_args.signaled = 0; + ret = ioctl(stress_device, NTSYNC_IOC_CREATE_EVENT, &event_args); + EXPECT_EQ(0, ret); + stress_start_event = event_args.event; + + for (i = 0; i < STRESS_THREADS; ++i) + pthread_create(&threads[i], NULL, stress_thread, NULL); + + ret = ioctl(stress_start_event, NTSYNC_IOC_EVENT_SET, &signaled); + EXPECT_EQ(0, ret); + + for (i = 0; i < STRESS_THREADS; ++i) { + ret = pthread_join(threads[i], NULL); + EXPECT_EQ(0, ret); + } + + EXPECT_EQ(STRESS_LOOPS * STRESS_THREADS, stress_counter); + + close(stress_start_event); + close(stress_mutex); + close(stress_device); +} + TEST_HARNESS_MAIN

Add an overall explanation of the driver architecture, and complete and precise specification for its intended behaviour.

Signed-off-by: Elizabeth Figura zfigura@codeweavers.com --- Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/ntsync.rst | 399 +++++++++++++++++++++++++ 2 files changed, 400 insertions(+) create mode 100644 Documentation/userspace-api/ntsync.rst

diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index 09f61bd2ac2e..f5a72ed27def 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -34,6 +34,7 @@ place where this information is gathered. tee isapnp dcdbas + ntsync

.. only:: subproject and html

diff --git a/Documentation/userspace-api/ntsync.rst b/Documentation/userspace-api/ntsync.rst new file mode 100644 index 000000000000..202c2350d3af --- /dev/null +++ b/Documentation/userspace-api/ntsync.rst @@ -0,0 +1,399 @@ +=================================== +NT synchronization primitive driver +=================================== + +This page documents the user-space API for the ntsync driver. + +ntsync is a support driver for emulation of NT synchronization +primitives by user-space NT emulators. It exists because implementation +in user-space, using existing tools, cannot match Windows performance +while offering accurate semantics. It is implemented entirely in +software, and does not drive any hardware device. + +This interface is meant as a compatibility tool only, and should not +be used for general synchronization. Instead use generic, versatile +interfaces such as futex(2) and poll(2). + +Synchronization primitives +========================== + +The ntsync driver exposes three types of synchronization primitives: +semaphores, mutexes, and events. + +A semaphore holds a single volatile 32-bit counter, and a static 32-bit +integer denoting the maximum value. It is considered signaled when the +counter is nonzero. The counter is decremented by one when a wait is +satisfied. Both the initial and maximum count are established when the +semaphore is created. + +A mutex holds a volatile 32-bit recursion count, and a volatile 32-bit +identifier denoting its owner. A mutex is considered signaled when its +owner is zero (indicating that it is not owned). The recursion count is +incremented when a wait is satisfied, and ownership is set to the given +identifier. + +A mutex also holds an internal flag denoting whether its previous owner +has died; such a mutex is said to be abandoned. Owner death is not +tracked automatically based on thread death, but rather must be +communicated using ``NTSYNC_IOC_MUTEX_KILL``. An abandoned mutex is +inherently considered unowned. + +Except for the "unowned" semantics of zero, the actual value of the +owner identifier is not interpreted by the ntsync driver at all. The +intended use is to store a thread identifier; however, the ntsync +driver does not actually validate that a calling thread provides +consistent or unique identifiers. + +An event holds a volatile boolean state denoting whether it is signaled +or not. There are two types of events, auto-reset and manual-reset. An +auto-reset event is designaled when a wait is satisfied; a manual-reset +event is not. The event type is specified when the event is created. + +Unless specified otherwise, all operations on an object are atomic and +totally ordered with respect to other operations on the same object. + +Objects are represented by files. When all file descriptors to an +object are closed, that object is deleted. + +Char device +=========== + +The ntsync driver creates a single char device /dev/ntsync. Each file +description opened on the device represents a unique instance intended +to back an individual NT virtual machine. Objects created by one ntsync +instance may only be used with other objects created by the same +instance. + +ioctl reference +=============== + +All operations on the device are done through ioctls. There are four +structures used in ioctl calls:: + + struct ntsync_sem_args { + __u32 sem; + __u32 count; + __u32 max; + }; + + struct ntsync_mutex_args { + __u32 mutex; + __u32 owner; + __u32 count; + }; + + struct ntsync_event_args { + __u32 event; + __u32 signaled; + __u32 manual; + }; + + struct ntsync_wait_args { + __u64 timeout; + __u64 objs; + __u32 count; + __u32 owner; + __u32 index; + __u32 alert; + __u32 flags; + __u32 pad; + }; + +Depending on the ioctl, members of the structure may be used as input, +output, or not at all. All ioctls return 0 on success. + +The ioctls on the device file are as follows: + +.. c:macro:: NTSYNC_IOC_CREATE_SEM + + Create a semaphore object. Takes a pointer to struct + :c:type:`ntsync_sem_args`, which is used as follows: + + .. list-table:: + + * - ``sem`` + - On output, contains a file descriptor to the created semaphore. + * - ``count`` + - Initial count of the semaphore. + * - ``max`` + - Maximum count of the semaphore. + + Fails with ``EINVAL`` if ``count`` is greater than ``max``. + +.. c:macro:: NTSYNC_IOC_CREATE_MUTEX + + Create a mutex object. Takes a pointer to struct + :c:type:`ntsync_mutex_args`, which is used as follows: + + .. list-table:: + + * - ``mutex`` + - On output, contains a file descriptor to the created mutex. + * - ``count`` + - Initial recursion count of the mutex. + * - ``owner`` + - Initial owner of the mutex. + + If ``owner`` is nonzero and ``count`` is zero, or if ``owner`` is + zero and ``count`` is nonzero, the function fails with ``EINVAL``. + +.. c:macro:: NTSYNC_IOC_CREATE_EVENT + + Create an event object. Takes a pointer to struct + :c:type:`ntsync_event_args`, which is used as follows: + + .. list-table:: + + * - ``event`` + - On output, contains a file descriptor to the created event. + * - ``signaled`` + - If nonzero, the event is initially signaled, otherwise + nonsignaled. + * - ``manual`` + - If nonzero, the event is a manual-reset event, otherwise + auto-reset. + +The ioctls on the individual objects are as follows: + +.. c:macro:: NTSYNC_IOC_SEM_POST + + Post to a semaphore object. Takes a pointer to a 32-bit integer, + which on input holds the count to be added to the semaphore, and on + output contains its previous count. + + If adding to the semaphore's current count would raise the latter + past the semaphore's maximum count, the ioctl fails with + ``EOVERFLOW`` and the semaphore is not affected. If raising the + semaphore's count causes it to become signaled, eligible threads + waiting on this semaphore will be woken and the semaphore's count + decremented appropriately. + +.. c:macro:: NTSYNC_IOC_MUTEX_UNLOCK + + Release a mutex object. Takes a pointer to struct + :c:type:`ntsync_mutex_args`, which is used as follows: + + .. list-table:: + + * - ``mutex`` + - Ignored. + * - ``owner`` + - Specifies the owner trying to release this mutex. + * - ``count`` + - On output, contains the previous recursion count. + + If ``owner`` is zero, the ioctl fails with ``EINVAL``. If ``owner`` + is not the current owner of the mutex, the ioctl fails with + ``EPERM``. + + The mutex's count will be decremented by one. If decrementing the + mutex's count causes it to become zero, the mutex is marked as + unowned and signaled, and eligible threads waiting on it will be + woken as appropriate. + +.. c:macro:: NTSYNC_IOC_SET_EVENT + + Signal an event object. Takes a pointer to a 32-bit integer, which on + output contains the previous state of the event. + + Eligible threads will be woken, and auto-reset events will be + designaled appropriately. + +.. c:macro:: NTSYNC_IOC_RESET_EVENT + + Designal an event object. Takes a pointer to a 32-bit integer, which + on output contains the previous state of the event. + +.. c:macro:: NTSYNC_IOC_PULSE_EVENT + + Wake threads waiting on an event object while leaving it in an + unsignaled state. Takes a pointer to a 32-bit integer, which on + output contains the previous state of the event. + + A pulse operation can be thought of as a set followed by a reset, + performed as a single atomic operation. If two threads are waiting on + an auto-reset event which is pulsed, only one will be woken. If two + threads are waiting a manual-reset event which is pulsed, both will + be woken. However, in both cases, the event will be unsignaled + afterwards, and a simultaneous read operation will always report the + event as unsignaled. + +.. c:macro:: NTSYNC_IOC_READ_SEM + + Read the current state of a semaphore object. Takes a pointer to + struct :c:type:`ntsync_sem_args`, which is used as follows: + + .. list-table:: + + * - ``sem`` + - Ignored. + * - ``count`` + - On output, contains the current count of the semaphore. + * - ``max`` + - On output, contains the maximum count of the semaphore. + +.. c:macro:: NTSYNC_IOC_READ_MUTEX + + Read the current state of a mutex object. Takes a pointer to struct + :c:type:`ntsync_mutex_args`, which is used as follows: + + .. list-table:: + + * - ``mutex`` + - Ignored. + * - ``owner`` + - On output, contains the current owner of the mutex, or zero + if the mutex is not currently owned. + * - ``count`` + - On output, contains the current recursion count of the mutex. + + If the mutex is marked as abandoned, the function fails with + ``EOWNERDEAD``. In this case, ``count`` and ``owner`` are set to + zero. + +.. c:macro:: NTSYNC_IOC_READ_EVENT + + Read the current state of an event object. Takes a pointer to struct + :c:type:`ntsync_event_args`, which is used as follows: + + .. list-table:: + + * - ``event`` + - Ignored. + * - ``signaled`` + - On output, contains the current state of the event. + * - ``manual`` + - On output, contains 1 if the event is a manual-reset event, + and 0 otherwise. + +.. c:macro:: NTSYNC_IOC_KILL_OWNER + + Mark a mutex as unowned and abandoned if it is owned by the given + owner. Takes an input-only pointer to a 32-bit integer denoting the + owner. If the owner is zero, the ioctl fails with ``EINVAL``. If the + owner does not own the mutex, the function fails with ``EPERM``. + + Eligible threads waiting on the mutex will be woken as appropriate + (and such waits will fail with ``EOWNERDEAD``, as described below). + +.. c:macro:: NTSYNC_IOC_WAIT_ANY + + Poll on any of a list of objects, atomically acquiring at most one. + Takes a pointer to struct :c:type:`ntsync_wait_args`, which is + used as follows: + + .. list-table:: + + * - ``timeout`` + - Absolute timeout in nanoseconds. If ``NTSYNC_WAIT_REALTIME`` + is set, the timeout is measured against the REALTIME clock; + otherwise it is measured against the MONOTONIC clock. If the + timeout is equal to or earlier than the current time, the + function returns immediately without sleeping. If ``timeout`` + is U64_MAX, the function will sleep until an object is + signaled, and will not fail with ``ETIMEDOUT``. + * - ``objs`` + - Pointer to an array of ``count`` file descriptors + (specified as an integer so that the structure has the same + size regardless of architecture). If any object is + invalid, the function fails with ``EINVAL``. + * - ``count`` + - Number of objects specified in the ``objs`` array. + If greater than ``NTSYNC_MAX_WAIT_COUNT``, the function fails + with ``EINVAL``. + * - ``owner`` + - Mutex owner identifier. If any object in ``objs`` is a mutex, + the ioctl will attempt to acquire that mutex on behalf of + ``owner``. If ``owner`` is zero, the ioctl fails with + ``EINVAL``. + * - ``index`` + - On success, contains the index (into ``objs``) of the object + which was signaled. If ``alert`` was signaled instead, + this contains ``count``. + * - ``alert`` + - Optional event object file descriptor. If nonzero, this + specifies an "alert" event object which, if signaled, will + terminate the wait. If nonzero, the identifier must point to a + valid event. + * - ``flags`` + - Zero or more flags. Currently the only flag is + ``NTSYNC_WAIT_REALTIME``, which causes the timeout to be + measured against the REALTIME clock instead of MONOTONIC. + * - ``pad`` + - Unused, must be set to zero. + + This function attempts to acquire one of the given objects. If unable + to do so, it sleeps until an object becomes signaled, subsequently + acquiring it, or the timeout expires. In the latter case the ioctl + fails with ``ETIMEDOUT``. The function only acquires one object, even + if multiple objects are signaled. + + A semaphore is considered to be signaled if its count is nonzero, and + is acquired by decrementing its count by one. A mutex is considered + to be signaled if it is unowned or if its owner matches the ``owner`` + argument, and is acquired by incrementing its recursion count by one + and setting its owner to the ``owner`` argument. An auto-reset event + is acquired by designaling it; a manual-reset event is not affected + by acquisition. + + Acquisition is atomic and totally ordered with respect to other + operations on the same object. If two wait operations (with different + ``owner`` identifiers) are queued on the same mutex, only one is + signaled. If two wait operations are queued on the same semaphore, + and a value of one is posted to it, only one is signaled. The order + in which threads are signaled is not specified. + + If an abandoned mutex is acquired, the ioctl fails with + ``EOWNERDEAD``. Although this is a failure return, the function may + otherwise be considered successful. The mutex is marked as owned by + the given owner (with a recursion count of 1) and as no longer + abandoned, and ``index`` is still set to the index of the mutex. + + The ``alert`` argument is an "extra" event which can terminate the + wait, independently of all other objects. If members of ``objs`` and + ``alert`` are both simultaneously signaled, a member of ``objs`` will + always be given priority and acquired first. + + It is valid to pass the same object more than once, including by + passing the same event in the ``objs`` array and in ``alert``. If a + wakeup occurs due to that object being signaled, ``index`` is set to + the lowest index corresponding to that object. + + The function may fail with ``EINTR`` if a signal is received. + +.. c:macro:: NTSYNC_IOC_WAIT_ALL + + Poll on a list of objects, atomically acquiring all of them. Takes a + pointer to struct :c:type:`ntsync_wait_args`, which is used + identically to ``NTSYNC_IOC_WAIT_ANY``, except that ``index`` is + always filled with zero on success if not woken via alert. + + This function attempts to simultaneously acquire all of the given + objects. If unable to do so, it sleeps until all objects become + simultaneously signaled, subsequently acquiring them, or the timeout + expires. In the latter case the ioctl fails with ``ETIMEDOUT`` and no + objects are modified. + + Objects may become signaled and subsequently designaled (through + acquisition by other threads) while this thread is sleeping. Only + once all objects are simultaneously signaled does the ioctl acquire + them and return. The entire acquisition is atomic and totally ordered + with respect to other operations on any of the given objects. + + If an abandoned mutex is acquired, the ioctl fails with + ``EOWNERDEAD``. Similarly to ``NTSYNC_IOC_WAIT_ANY``, all objects are + nevertheless marked as acquired. Note that if multiple mutex objects + are specified, there is no way to know which were marked as + abandoned. + + As with "any" waits, the ``alert`` argument is an "extra" event which + can terminate the wait. Critically, however, an "all" wait will + succeed if all members in ``objs`` are signaled, *or* if ``alert`` is + signaled. In the latter case ``index`` will be set to ``count``. As + with "any" waits, if both conditions are filled, the former takes + priority, and objects in ``objs`` will be acquired. + + Unlike ``NTSYNC_IOC_WAIT_ANY``, it is not valid to pass the same + object more than once, nor is it valid to pass the same object in + ``objs`` and in ``alert``. If this is attempted, the function fails + with ``EINVAL``.