From 09ac4fcb3f255e9225967c75f5893325c116cdbe Mon Sep 17 00:00:00 2001 From: Felix Kuehling Date: Thu, 13 Jul 2017 17:01:16 -0400 Subject: [PATCH] drm/ttm: Implement vm_operations_struct.access v2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Christian König Reviewed-by: Michel Dänzer Signed-off-by: Alex Deucher --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 79 ++++++++++++++++++++++++++++++++- include/drm/ttm/ttm_bo_driver.h | 17 +++++++ 2 files changed, 95 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index b442d12f2f7d..a01e5c90fd87 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, diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index 990d529f823c..d30850e07936 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -472,6 +472,23 @@ struct ttm_bo_driver { */ unsigned long (*io_mem_pfn)(struct ttm_buffer_object *bo, unsigned long page_offset); + + /** + * Read/write memory buffers for ptrace access + * + * @bo: the BO to access + * @offset: the offset from the start of the BO + * @buf: pointer to source/destination buffer + * @len: number of bytes to copy + * @write: whether to read (0) from or write (non-0) to BO + * + * If successful, this function should return the number of + * bytes copied, -EIO otherwise. If the number of bytes + * returned is < len, the function may be called again with + * the remainder of the buffer to copy. + */ + int (*access_memory)(struct ttm_buffer_object *bo, unsigned long offset, + void *buf, int len, int write); }; /** -- 2.20.1