drm/ttm: Implement vm_operations_struct.access v2
Allows gdb to access contents of user mode mapped BOs. System memory
is handled by TTM using kmap. Other memory pools require a new driver
callback in ttm_bo_driver.
v2:
* kmap only one page at a time
* swap in BO if needed
* make driver callback more generic to handle private memory pools
* document callback return value
* WARN_ON -> WARN_ON_ONCE
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index b442d12..a01e5c9 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -294,10 +294,87 @@ static void ttm_bo_vm_close(struct vm_area_struct *vma)
vma->vm_private_data = NULL;
}
+static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
+ unsigned long offset,
+ void *buf, int len, int write)
+{
+ unsigned long page = offset >> PAGE_SHIFT;
+ unsigned long bytes_left = len;
+ int ret;
+
+ /* Copy a page at a time, that way no extra virtual address
+ * mapping is needed
+ */
+ offset -= page << PAGE_SHIFT;
+ do {
+ unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
+ struct ttm_bo_kmap_obj map;
+ void *ptr;
+ bool is_iomem;
+
+ ret = ttm_bo_kmap(bo, page, 1, &map);
+ if (ret)
+ return ret;
+
+ ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
+ WARN_ON_ONCE(is_iomem);
+ if (write)
+ memcpy(ptr, buf, bytes);
+ else
+ memcpy(buf, ptr, bytes);
+ ttm_bo_kunmap(&map);
+
+ page++;
+ bytes_left -= bytes;
+ offset = 0;
+ } while (bytes_left);
+
+ return len;
+}
+
+static int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+ unsigned long offset = (addr) - vma->vm_start;
+ struct ttm_buffer_object *bo = vma->vm_private_data;
+ int ret;
+
+ if (len < 1 || (offset + len) >> PAGE_SHIFT > bo->num_pages)
+ return -EIO;
+
+ ret = ttm_bo_reserve(bo, true, false, NULL);
+ if (ret)
+ return ret;
+
+ switch (bo->mem.mem_type) {
+ case TTM_PL_SYSTEM:
+ if (unlikely(bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
+ ret = ttm_tt_swapin(bo->ttm);
+ if (unlikely(ret != 0))
+ return ret;
+ }
+ /* fall through */
+ case TTM_PL_TT:
+ ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
+ break;
+ default:
+ if (bo->bdev->driver->access_memory)
+ ret = bo->bdev->driver->access_memory(
+ bo, offset, buf, len, write);
+ else
+ ret = -EIO;
+ }
+
+ ttm_bo_unreserve(bo);
+
+ return ret;
+}
+
static const struct vm_operations_struct ttm_bo_vm_ops = {
.fault = ttm_bo_vm_fault,
.open = ttm_bo_vm_open,
- .close = ttm_bo_vm_close
+ .close = ttm_bo_vm_close,
+ .access = ttm_bo_vm_access
};
static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,