habanalabs: add page fault info uapi

Only the first page fault will be saved.
Besides the address which caused the page fault, the driver captures
all of the mmu user mappings.
User can retrieve this data via the new uapi (new opcode in INFO ioctl).

Signed-off-by: Dani Liberman <dliberman@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index 30ddaaae67e5..5dc6c77b4721 100644
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -12,6 +12,7 @@
 
 #include <linux/pci.h>
 #include <linux/hwmon.h>
+#include <linux/vmalloc.h>
 
 #include <trace/events/habanalabs.h>
 
@@ -2199,6 +2200,8 @@ void hl_device_fini(struct hl_device *hdev)
 
 	hl_mmu_fini(hdev);
 
+	vfree(hdev->captured_err_info.pgf_info.user_mappings);
+
 	hl_eq_fini(hdev, &hdev->event_queue);
 
 	kfree(hdev->shadow_cs_queue);
@@ -2275,3 +2278,58 @@ void hl_capture_razwi(struct hl_device *hdev, u64 addr, u16 *engine_id, u16 num_
 			num_of_engines * sizeof(u16));
 	hdev->captured_err_info.razwi.flags = flags;
 }
+static void hl_capture_user_mappings(struct hl_device *hdev)
+{
+	struct page_fault_info *pgf_info = &hdev->captured_err_info.pgf_info;
+	struct hl_vm_hash_node *hnode;
+	struct hl_userptr *userptr;
+	struct hl_ctx *ctx;
+	u32 map_idx = 0;
+	int i;
+
+	ctx = hl_get_compute_ctx(hdev);
+	if (!ctx) {
+		dev_err(hdev->dev, "Can't get user context for user mappings\n");
+		return;
+	}
+
+	mutex_lock(&ctx->mem_hash_lock);
+	hash_for_each(ctx->mem_hash, i, hnode, node)
+	pgf_info->num_of_user_mappings++;
+
+	if (!pgf_info->num_of_user_mappings)
+		goto finish;
+
+	/* In case we already allocated in previous session, need to release it before
+	 * allocating new buffer.
+	 */
+	vfree(pgf_info->user_mappings);
+	pgf_info->user_mappings =
+			vmalloc(pgf_info->num_of_user_mappings * sizeof(struct hl_user_mapping));
+	if (!pgf_info->user_mappings) {
+		pgf_info->num_of_user_mappings = 0;
+		goto finish;
+	}
+
+	hash_for_each(ctx->mem_hash, i, hnode, node) {
+		userptr = hnode->ptr;
+		pgf_info->user_mappings[map_idx].dev_va = hnode->vaddr;
+		pgf_info->user_mappings[map_idx].size = userptr->size;
+		map_idx++;
+	}
+finish:
+	mutex_unlock(&ctx->mem_hash_lock);
+	hl_ctx_put(ctx);
+}
+
+void hl_capture_page_fault(struct hl_device *hdev, u64 addr, u16 eng_id, bool is_pmmu)
+{
+	/* Capture only the first page fault */
+	if (atomic_cmpxchg(&hdev->captured_err_info.pgf_info_recorded, 0, 1))
+		return;
+
+	hdev->captured_err_info.pgf_info.pgf.timestamp = ktime_to_ns(ktime_get());
+	hdev->captured_err_info.pgf_info.pgf.addr = addr;
+	hdev->captured_err_info.pgf_info.pgf.engine_id = eng_id;
+	hl_capture_user_mappings(hdev);
+}