1 files changed, 27 insertions, 9 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cper.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cper.c
index c72c345334d0..4e6e390854e6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cper.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cper.c
@@ -32,6 +32,8 @@ static const guid_t BOOT		= BOOT_TYPE;
 static const guid_t CRASHDUMP		= AMD_CRASHDUMP;
 static const guid_t RUNTIME		= AMD_GPU_NONSTANDARD_ERROR;
 
+#define CPER_SIGNATURE_SZ		(sizeof(((struct cper_hdr *)0)->signature))
+
 static void __inc_entry_length(struct cper_hdr *hdr, uint32_t size)
 {
 	hdr->record_length += size;
@@ -425,23 +427,40 @@ int amdgpu_cper_generate_ce_records(struct amdgpu_device *adev,
 
 static bool amdgpu_cper_is_hdr(struct amdgpu_ring *ring, u64 pos)
 {
-	struct cper_hdr *chdr;
+	char signature[CPER_SIGNATURE_SZ];
+
+	if ((pos << 2) >= ring->ring_size)
+		return false;
 
-	chdr = (struct cper_hdr *)&(ring->ring[pos]);
-	return strcmp(chdr->signature, "CPER") ? false : true;
+	if ((pos << 2) + CPER_SIGNATURE_SZ <= ring->ring_size) {
+		memcpy(signature, &ring->ring[pos], CPER_SIGNATURE_SZ);
+	} else {
+		u32 chunk = ring->ring_size - (pos << 2);
+
+		memcpy(signature, &ring->ring[pos], chunk);
+		memcpy(signature + chunk, ring->ring, CPER_SIGNATURE_SZ - chunk);
+	}
+
+	return !memcmp(signature, "CPER", CPER_SIGNATURE_SZ);
 }
 
 static u32 amdgpu_cper_ring_get_ent_sz(struct amdgpu_ring *ring, u64 pos)
 {
-	struct cper_hdr *chdr;
+	struct cper_hdr chdr;
 	u64 p;
 	u32 chunk, rec_len = 0;
 
-	chdr = (struct cper_hdr *)&(ring->ring[pos]);
 	chunk = ring->ring_size - (pos << 2);
 
-	if (!strcmp(chdr->signature, "CPER")) {
-		rec_len = chdr->record_length;
+	if (amdgpu_cper_is_hdr(ring, pos)) {
+		if (chunk >= sizeof(chdr)) {
+			memcpy(&chdr, &ring->ring[pos], sizeof(chdr));
+		} else {
+			memcpy(&chdr, &ring->ring[pos], chunk);
+			memcpy((u8 *)&chdr + chunk, ring->ring, sizeof(chdr) - chunk);
+		}
+
+		rec_len = chdr.record_length;
 		goto calc;
 	}
 
@@ -450,8 +469,7 @@ static u32 amdgpu_cper_ring_get_ent_sz(struct amdgpu_ring *ring, u64 pos)
 		goto calc;
 
 	for (p = pos + 1; p <= ring->buf_mask; p++) {
-		chdr = (struct cper_hdr *)&(ring->ring[p]);
-		if (!strcmp(chdr->signature, "CPER")) {
+		if (amdgpu_cper_is_hdr(ring, p)) {
 			rec_len = (p - pos) << 2;
 			goto calc;
 		}