Legacy CPER ring readers can issue one debugfs read with a buffer larger
than the UNIRAS RAS command payload limit. Passing that full size to
GET_CPER_RECORD makes the command reject the request, so userspace may
only see the ring prefix and treat the CPER stream as empty.
Commit 07d0ee31a5d6 ("drm/amd/ras: bound CPER record fetch buffer
size") intentionally bounds CPER record fetch allocation by the command
buffer size. Keep the debugfs ABI as a single contiguous ring read by
splitting the internal GET_CPER_RECORD requests into
RAS_CMD_MAX_CPER_BUF_SZ chunks.
Accumulate the copied payload and update the legacy header write pointers
from the total bytes returned to userspace.
Signed-off-by: Xiang Liu <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 49 ++++++++++++++++--------
1 file changed, 33 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index e8cee3728ade..5dc00db14a32 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -501,6 +501,8 @@ static ssize_t amdgpu_ras_cper_debugfs_read(struct file *f,
char __user *buf,
u32 total_cper_num;
u64 start_cper_id;
u64 cper_offset;
+ size_t chunk_size;
+ size_t total_data_size = 0;
bool read_header;
int r;
@@ -550,30 +552,45 @@ static ssize_t amdgpu_ras_cper_debugfs_read(struct file
*f, char __user *buf,
if (!data_size)
return 0;
- record_req->buf_ptr = (u64)(uintptr_t)data_buf;
- record_req->buf_size = data_size;
- record_req->cper_start_id = start_cper_id + cper_offset;
- record_req->cper_num = total_cper_num - cper_offset;
- r = amdgpu_ras_mgr_handle_ras_cmd(ring->adev,
- RAS_CMD__GET_CPER_RECORD,
- record_req, sizeof(struct
ras_cmd_cper_record_req),
- record_rsp, sizeof(struct
ras_cmd_cper_record_rsp));
- if (r)
- return r;
- if (record_rsp->real_data_size > data_size)
- return -EIO;
+ while (data_size && cper_offset < total_cper_num) {
+ memset(record_req, 0, sizeof(*record_req));
+ memset(record_rsp, 0, sizeof(*record_rsp));
+ chunk_size = min_t(size_t, data_size, RAS_CMD_MAX_CPER_BUF_SZ);
+
+ record_req->buf_ptr = (u64)(uintptr_t)data_buf;
+ record_req->buf_size = chunk_size;
+ record_req->cper_start_id = start_cper_id + cper_offset;
+ record_req->cper_num = total_cper_num - cper_offset;
+ r = amdgpu_ras_mgr_handle_ras_cmd(ring->adev,
+ RAS_CMD__GET_CPER_RECORD,
+ record_req,
+ sizeof(struct
ras_cmd_cper_record_req),
+ record_rsp,
+ sizeof(struct
ras_cmd_cper_record_rsp));
+ if (r)
+ return r;
+
+ if (!record_rsp->real_data_size || !record_rsp->real_cper_num)
+ break;
+ if (record_rsp->real_data_size > data_size)
+ return -EIO;
+
+ data_buf += record_rsp->real_data_size;
+ data_size -= record_rsp->real_data_size;
+ total_data_size += record_rsp->real_data_size;
+ cper_offset += record_rsp->real_cper_num;
+ }
if (read_header) {
- ring_header[1] = record_rsp->real_data_size >> 2;
+ ring_header[1] = total_data_size >> 2;
ring_header[2] = ring_header[1];
if (copy_to_user(buf, ring_header, ring_header_size))
return -EFAULT;
}
- r = read_header ? record_rsp->real_data_size + ring_header_size :
- record_rsp->real_data_size;
- *offset = cper_offset + record_rsp->real_cper_num + 1;
+ r = read_header ? total_data_size + ring_header_size : total_data_size;
+ *offset = cper_offset + 1;
return r;
}
--
2.34.1
