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Subject[PATCH 5.14 080/100] habanalabs: fix race between soft reset and heartbeat
Date
From: Koby Elbaz <kelbaz@habana.ai>

[ Upstream commit 8bb8b505761238be0d6a83dc41188867d65e5d4c ]

There is a scenario where an ongoing soft reset would race with an
ongoing heartbeat routine, eventually causing heartbeat to fail and
thus to escalate into a hard reset.

With this fix, soft-reset procedure will disable heartbeat CPU messages
and flush the (ongoing) current one before continuing with reset code.

Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/misc/habanalabs/common/device.c | 53 +++++++++++++++-----
drivers/misc/habanalabs/common/firmware_if.c | 18 +++++--
drivers/misc/habanalabs/common/habanalabs.h | 4 +-
drivers/misc/habanalabs/common/hw_queue.c | 30 ++++-------
4 files changed, 67 insertions(+), 38 deletions(-)

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index ff4cbde289c0..0a788a13f2c1 100644
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -682,6 +682,44 @@ out:
return rc;
}

+static void take_release_locks(struct hl_device *hdev)
+{
+ /* Flush anyone that is inside the critical section of enqueue
+ * jobs to the H/W
+ */
+ hdev->asic_funcs->hw_queues_lock(hdev);
+ hdev->asic_funcs->hw_queues_unlock(hdev);
+
+ /* Flush processes that are sending message to CPU */
+ mutex_lock(&hdev->send_cpu_message_lock);
+ mutex_unlock(&hdev->send_cpu_message_lock);
+
+ /* Flush anyone that is inside device open */
+ mutex_lock(&hdev->fpriv_list_lock);
+ mutex_unlock(&hdev->fpriv_list_lock);
+}
+
+static void cleanup_resources(struct hl_device *hdev, bool hard_reset)
+{
+ if (hard_reset)
+ device_late_fini(hdev);
+
+ /*
+ * Halt the engines and disable interrupts so we won't get any more
+ * completions from H/W and we won't have any accesses from the
+ * H/W to the host machine
+ */
+ hdev->asic_funcs->halt_engines(hdev, hard_reset);
+
+ /* Go over all the queues, release all CS and their jobs */
+ hl_cs_rollback_all(hdev);
+
+ /* Release all pending user interrupts, each pending user interrupt
+ * holds a reference to user context
+ */
+ hl_release_pending_user_interrupts(hdev);
+}
+
/*
* hl_device_suspend - initiate device suspend
*
@@ -707,16 +745,7 @@ int hl_device_suspend(struct hl_device *hdev)
/* This blocks all other stuff that is not blocked by in_reset */
hdev->disabled = true;

- /*
- * Flush anyone that is inside the critical section of enqueue
- * jobs to the H/W
- */
- hdev->asic_funcs->hw_queues_lock(hdev);
- hdev->asic_funcs->hw_queues_unlock(hdev);
-
- /* Flush processes that are sending message to CPU */
- mutex_lock(&hdev->send_cpu_message_lock);
- mutex_unlock(&hdev->send_cpu_message_lock);
+ take_release_locks(hdev);

rc = hdev->asic_funcs->suspend(hdev);
if (rc)
@@ -894,8 +923,8 @@ int hl_device_reset(struct hl_device *hdev, u32 flags)
return 0;
}

- hard_reset = (flags & HL_RESET_HARD) != 0;
- from_hard_reset_thread = (flags & HL_RESET_FROM_RESET_THREAD) != 0;
+ hard_reset = !!(flags & HL_RESET_HARD);
+ from_hard_reset_thread = !!(flags & HL_RESET_FROM_RESET_THREAD);

if (!hard_reset && !hdev->supports_soft_reset) {
hard_instead_soft = true;
diff --git a/drivers/misc/habanalabs/common/firmware_if.c b/drivers/misc/habanalabs/common/firmware_if.c
index 2e4d04ec6b53..653e8f5ef6ac 100644
--- a/drivers/misc/habanalabs/common/firmware_if.c
+++ b/drivers/misc/habanalabs/common/firmware_if.c
@@ -240,11 +240,15 @@ int hl_fw_send_cpu_message(struct hl_device *hdev, u32 hw_queue_id, u32 *msg,
/* set fence to a non valid value */
pkt->fence = cpu_to_le32(UINT_MAX);

- rc = hl_hw_queue_send_cb_no_cmpl(hdev, hw_queue_id, len, pkt_dma_addr);
- if (rc) {
- dev_err(hdev->dev, "Failed to send CB on CPU PQ (%d)\n", rc);
- goto out;
- }
+ /*
+ * The CPU queue is a synchronous queue with an effective depth of
+ * a single entry (although it is allocated with room for multiple
+ * entries). We lock on it using 'send_cpu_message_lock' which
+ * serializes accesses to the CPU queue.
+ * Which means that we don't need to lock the access to the entire H/W
+ * queues module when submitting a JOB to the CPU queue.
+ */
+ hl_hw_queue_submit_bd(hdev, queue, 0, len, pkt_dma_addr);

if (prop->fw_app_cpu_boot_dev_sts0 & CPU_BOOT_DEV_STS0_PKT_PI_ACK_EN)
expected_ack_val = queue->pi;
@@ -2235,6 +2239,10 @@ static int hl_fw_dynamic_init_cpu(struct hl_device *hdev,
dev_info(hdev->dev,
"Loading firmware to device, may take some time...\n");

+ /*
+ * In this stage, "cpu_dyn_regs" contains only LKD's hard coded values!
+ * It will be updated from FW after hl_fw_dynamic_request_descriptor().
+ */
dyn_regs = &fw_loader->dynamic_loader.comm_desc.cpu_dyn_regs;

rc = hl_fw_dynamic_send_protocol_cmd(hdev, fw_loader, COMMS_RST_STATE,
diff --git a/drivers/misc/habanalabs/common/habanalabs.h b/drivers/misc/habanalabs/common/habanalabs.h
index 6b3cdd7e068a..c63e26da5135 100644
--- a/drivers/misc/habanalabs/common/habanalabs.h
+++ b/drivers/misc/habanalabs/common/habanalabs.h
@@ -2436,7 +2436,9 @@ void destroy_hdev(struct hl_device *hdev);
int hl_hw_queues_create(struct hl_device *hdev);
void hl_hw_queues_destroy(struct hl_device *hdev);
int hl_hw_queue_send_cb_no_cmpl(struct hl_device *hdev, u32 hw_queue_id,
- u32 cb_size, u64 cb_ptr);
+ u32 cb_size, u64 cb_ptr);
+void hl_hw_queue_submit_bd(struct hl_device *hdev, struct hl_hw_queue *q,
+ u32 ctl, u32 len, u64 ptr);
int hl_hw_queue_schedule_cs(struct hl_cs *cs);
u32 hl_hw_queue_add_ptr(u32 ptr, u16 val);
void hl_hw_queue_inc_ci_kernel(struct hl_device *hdev, u32 hw_queue_id);
diff --git a/drivers/misc/habanalabs/common/hw_queue.c b/drivers/misc/habanalabs/common/hw_queue.c
index bcabfdbf1e01..0afead229e97 100644
--- a/drivers/misc/habanalabs/common/hw_queue.c
+++ b/drivers/misc/habanalabs/common/hw_queue.c
@@ -65,7 +65,7 @@ void hl_hw_queue_update_ci(struct hl_cs *cs)
}

/*
- * ext_and_hw_queue_submit_bd() - Submit a buffer descriptor to an external or a
+ * hl_hw_queue_submit_bd() - Submit a buffer descriptor to an external or a
* H/W queue.
* @hdev: pointer to habanalabs device structure
* @q: pointer to habanalabs queue structure
@@ -80,8 +80,8 @@ void hl_hw_queue_update_ci(struct hl_cs *cs)
* This function must be called when the scheduler mutex is taken
*
*/
-static void ext_and_hw_queue_submit_bd(struct hl_device *hdev,
- struct hl_hw_queue *q, u32 ctl, u32 len, u64 ptr)
+void hl_hw_queue_submit_bd(struct hl_device *hdev, struct hl_hw_queue *q,
+ u32 ctl, u32 len, u64 ptr)
{
struct hl_bd *bd;

@@ -222,8 +222,8 @@ static int hw_queue_sanity_checks(struct hl_device *hdev, struct hl_hw_queue *q,
* @cb_size: size of CB
* @cb_ptr: pointer to CB location
*
- * This function sends a single CB, that must NOT generate a completion entry
- *
+ * This function sends a single CB, that must NOT generate a completion entry.
+ * Sending CPU messages can be done instead via 'hl_hw_queue_submit_bd()'
*/
int hl_hw_queue_send_cb_no_cmpl(struct hl_device *hdev, u32 hw_queue_id,
u32 cb_size, u64 cb_ptr)
@@ -231,16 +231,7 @@ int hl_hw_queue_send_cb_no_cmpl(struct hl_device *hdev, u32 hw_queue_id,
struct hl_hw_queue *q = &hdev->kernel_queues[hw_queue_id];
int rc = 0;

- /*
- * The CPU queue is a synchronous queue with an effective depth of
- * a single entry (although it is allocated with room for multiple
- * entries). Therefore, there is a different lock, called
- * send_cpu_message_lock, that serializes accesses to the CPU queue.
- * As a result, we don't need to lock the access to the entire H/W
- * queues module when submitting a JOB to the CPU queue
- */
- if (q->queue_type != QUEUE_TYPE_CPU)
- hdev->asic_funcs->hw_queues_lock(hdev);
+ hdev->asic_funcs->hw_queues_lock(hdev);

if (hdev->disabled) {
rc = -EPERM;
@@ -258,11 +249,10 @@ int hl_hw_queue_send_cb_no_cmpl(struct hl_device *hdev, u32 hw_queue_id,
goto out;
}

- ext_and_hw_queue_submit_bd(hdev, q, 0, cb_size, cb_ptr);
+ hl_hw_queue_submit_bd(hdev, q, 0, cb_size, cb_ptr);

out:
- if (q->queue_type != QUEUE_TYPE_CPU)
- hdev->asic_funcs->hw_queues_unlock(hdev);
+ hdev->asic_funcs->hw_queues_unlock(hdev);

return rc;
}
@@ -328,7 +318,7 @@ static void ext_queue_schedule_job(struct hl_cs_job *job)
cq->pi = hl_cq_inc_ptr(cq->pi);

submit_bd:
- ext_and_hw_queue_submit_bd(hdev, q, ctl, len, ptr);
+ hl_hw_queue_submit_bd(hdev, q, ctl, len, ptr);
}

/*
@@ -407,7 +397,7 @@ static void hw_queue_schedule_job(struct hl_cs_job *job)
else
ptr = (u64) (uintptr_t) job->user_cb;

- ext_and_hw_queue_submit_bd(hdev, q, ctl, len, ptr);
+ hl_hw_queue_submit_bd(hdev, q, ctl, len, ptr);
}

static int init_signal_cs(struct hl_device *hdev,
--
2.33.0


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