Commit 42eb2872 authored by Ofir Bitton's avatar Ofir Bitton Committed by Oded Gabbay
Browse files

habanalabs: add a lock to protect multiple reset variables 



Atomic operations during reset are replaced by a spinlock in order
to have the ability to protect more than a single variable.

Signed-off-by: default avatarOfir Bitton <obitton@habana.ai>
Reviewed-by: default avatarOded Gabbay <ogabbay@kernel.org>
Signed-off-by: default avatarOded Gabbay <ogabbay@kernel.org>
parent eb135291

drivers/misc/habanalabs/common/command_buffer.c

+1 −2
Original line number Diff line number Diff line
@@ -250,8 +250,7 @@ int hl_cb_create(struct hl_device *hdev, struct hl_cb_mgr *mgr, 
	 * Can't use generic function to check this because of special case

	 * where we create a CB as part of the reset process

	 */

	if ((hdev->disabled) || ((atomic_read(&hdev->reset_info.in_reset)) &&

					(ctx_id != HL_KERNEL_ASID_ID))) {

	if ((hdev->disabled) || (hdev->reset_info.in_reset && (ctx_id != HL_KERNEL_ASID_ID))) {

		dev_warn_ratelimited(hdev->dev,

			"Device is disabled or in reset. Can't create new CBs\n");

		rc = -EBUSY;

drivers/misc/habanalabs/common/debugfs.c

+8 −8
Original line number Diff line number Diff line
@@ -527,7 +527,7 @@ static int engines_show(struct seq_file *s, void *data) 
	struct hl_dbg_device_entry *dev_entry = entry->dev_entry;

	struct hl_device *hdev = dev_entry->hdev;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev,

				"Can't check device idle during reset\n");

		return 0;
@@ -658,7 +658,7 @@ static ssize_t hl_data_read32(struct file *f, char __user *buf, 
	ssize_t rc;

	u32 val;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev, "Can't read during reset\n");

		return 0;

	}
@@ -694,7 +694,7 @@ static ssize_t hl_data_write32(struct file *f, const char __user *buf, 
	u32 value;

	ssize_t rc;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev, "Can't write during reset\n");

		return 0;

	}
@@ -731,7 +731,7 @@ static ssize_t hl_data_read64(struct file *f, char __user *buf, 
	ssize_t rc;

	u64 val;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev, "Can't read during reset\n");

		return 0;

	}
@@ -767,7 +767,7 @@ static ssize_t hl_data_write64(struct file *f, const char __user *buf, 
	u64 value;

	ssize_t rc;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev, "Can't write during reset\n");

		return 0;

	}
@@ -802,7 +802,7 @@ static ssize_t hl_dma_size_write(struct file *f, const char __user *buf, 
	ssize_t rc;

	u32 size;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev, "Can't DMA during reset\n");

		return 0;

	}
@@ -1077,7 +1077,7 @@ static ssize_t hl_clk_gate_write(struct file *f, const char __user *buf, 
	u64 value;

	ssize_t rc;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev,

				"Can't change clock gating during reset\n");

		return 0;
@@ -1119,7 +1119,7 @@ static ssize_t hl_stop_on_err_write(struct file *f, const char __user *buf, 
	u32 value;

	ssize_t rc;



	if (atomic_read(&hdev->reset_info.in_reset)) {

	if (hdev->reset_info.in_reset) {

		dev_warn_ratelimited(hdev->dev,

				"Can't change stop on error during reset\n");

		return 0;

drivers/misc/habanalabs/common/device.c

+36 −14
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ enum hl_device_status hl_device_status(struct hl_device *hdev) 
{

	enum hl_device_status status;



	if (atomic_read(&hdev->reset_info.in_reset))

	if (hdev->reset_info.in_reset)

		status = HL_DEVICE_STATUS_IN_RESET;

	else if (hdev->reset_info.needs_reset)

		status = HL_DEVICE_STATUS_NEEDS_RESET;
@@ -448,11 +448,11 @@ static int device_early_init(struct hl_device *hdev) 
	mutex_init(&hdev->debug_lock);

	INIT_LIST_HEAD(&hdev->cs_mirror_list);

	spin_lock_init(&hdev->cs_mirror_lock);

	spin_lock_init(&hdev->reset_info.lock);

	INIT_LIST_HEAD(&hdev->fpriv_list);

	INIT_LIST_HEAD(&hdev->fpriv_ctrl_list);

	mutex_init(&hdev->fpriv_list_lock);

	mutex_init(&hdev->fpriv_ctrl_list_lock);

	atomic_set(&hdev->reset_info.in_reset, 0);

	mutex_init(&hdev->clk_throttling.lock);



	return 0;
@@ -544,7 +544,7 @@ static void hl_device_heartbeat(struct work_struct *work) 
	 * status for at least one heartbeat. From this point driver restarts

	 * tracking future consecutive fatal errors.

	 */

	if (!(atomic_read(&hdev->reset_info.in_reset)))

	if (!hdev->reset_info.in_reset)

		hdev->reset_info.prev_reset_trigger = HL_RESET_TRIGGER_DEFAULT;



	schedule_delayed_work(&hdev->work_heartbeat,
@@ -722,11 +722,14 @@ int hl_device_suspend(struct hl_device *hdev) 
	pci_save_state(hdev->pdev);



	/* Block future CS/VM/JOB completion operations */

	rc = atomic_cmpxchg(&hdev->reset_info.in_reset, 0, 1);

	if (rc) {

	spin_lock(&hdev->reset_info.lock);

	if (hdev->reset_info.in_reset) {

		spin_unlock(&hdev->reset_info.lock);

		dev_err(hdev->dev, "Can't suspend while in reset\n");

		return -EIO;

	}

	hdev->reset_info.in_reset = 1;

	spin_unlock(&hdev->reset_info.lock);



	/* This blocks all other stuff that is not blocked by in_reset */

	hdev->disabled = true;
@@ -776,8 +779,10 @@ int hl_device_resume(struct hl_device *hdev) 
	}





	hdev->disabled = false;

	atomic_set(&hdev->reset_info.in_reset, 0);

	/* 'in_reset' was set to true during suspend, now we must clear it in order

	 * for hard reset to be performed

	 */

	hdev->reset_info.in_reset = 0;



	rc = hl_device_reset(hdev, HL_DRV_RESET_HARD);

	if (rc) {
@@ -1024,9 +1029,13 @@ int hl_device_reset(struct hl_device *hdev, u32 flags) 
	 */

	if (!from_hard_reset_thread) {

		/* Block future CS/VM/JOB completion operations */

		rc = atomic_cmpxchg(&hdev->reset_info.in_reset, 0, 1);

		if (rc)

		spin_lock(&hdev->reset_info.lock);

		if (hdev->reset_info.in_reset) {

			spin_unlock(&hdev->reset_info.lock);

			return 0;

		}

		hdev->reset_info.in_reset = 1;

		spin_unlock(&hdev->reset_info.lock);



		handle_reset_trigger(hdev, flags);
@@ -1234,7 +1243,7 @@ int hl_device_reset(struct hl_device *hdev, u32 flags) 
		}

	}



	atomic_set(&hdev->reset_info.in_reset, 0);

	hdev->reset_info.in_reset = 0;

	hdev->reset_info.needs_reset = false;



	dev_notice(hdev->dev, "Successfully finished resetting the device\n");
@@ -1272,7 +1281,7 @@ int hl_device_reset(struct hl_device *hdev, u32 flags) 
		goto again;

	}



	atomic_set(&hdev->reset_info.in_reset, 0);

	hdev->reset_info.in_reset = 0;



	return rc;

}
@@ -1583,6 +1592,7 @@ int hl_device_init(struct hl_device *hdev, struct class *hclass) 
 */

void hl_device_fini(struct hl_device *hdev)

{

	bool device_in_reset;

	ktime_t timeout;

	u64 reset_sec;

	int i, rc;
@@ -1606,10 +1616,22 @@ void hl_device_fini(struct hl_device *hdev) 
	 */



	timeout = ktime_add_us(ktime_get(), reset_sec * 1000 * 1000);

	rc = atomic_cmpxchg(&hdev->reset_info.in_reset, 0, 1);

	while (rc) {



	spin_lock(&hdev->reset_info.lock);

	device_in_reset = !!hdev->reset_info.in_reset;

	if (!device_in_reset)

		hdev->reset_info.in_reset = 1;

	spin_unlock(&hdev->reset_info.lock);



	while (device_in_reset) {

		usleep_range(50, 200);

		rc = atomic_cmpxchg(&hdev->reset_info.in_reset, 0, 1);



		spin_lock(&hdev->reset_info.lock);

		device_in_reset = !!hdev->reset_info.in_reset;

		if (!device_in_reset)

			hdev->reset_info.in_reset = 1;

		spin_unlock(&hdev->reset_info.lock);



		if (ktime_compare(ktime_get(), timeout) > 0) {

			dev_crit(hdev->dev,

				"Failed to remove device because reset function did not finish\n");

drivers/misc/habanalabs/common/habanalabs.h

+4 −2
Original line number Diff line number Diff line
@@ -2457,9 +2457,10 @@ struct last_error_session_info { 


/**

 * struct hl_reset_info - holds current device reset information.

 * @in_reset: is device in reset flow.

 * @lock: lock to protect critical reset flows.

 * @soft_reset_cnt: number of soft reset since the driver was loaded.

 * @hard_reset_cnt: number of hard reset since the driver was loaded.

 * @in_reset: is device in reset flow.

 * @is_in_soft_reset: Device is currently in soft reset process.

 * @needs_reset: true if reset_on_lockup is false and device should be reset

 *               due to lockup.
@@ -2474,9 +2475,10 @@ struct last_error_session_info { 
 *                         complete instead.

 */

struct hl_reset_info {

	atomic_t	in_reset;

	spinlock_t	lock;

	u32		soft_reset_cnt;

	u32		hard_reset_cnt;

	u8		in_reset;

	u8		is_in_soft_reset;

	u8		needs_reset;

	u8		hard_reset_pending;