kernel/include/linux/dma-mapping.h, branch linux-5.10.y

dma-mapping: avoid potential unused data compilation warning

2025-06-04T12:36:58Z

[ Upstream commit c9b19ea63036fc537a69265acea1b18dabd1cbd3 ] When CONFIG_NEED_DMA_MAP_STATE is not defined, dma-mapping clients might report unused data compilation warnings for dma_unmap_*() calls arguments. Redefine macros for those calls to let compiler to notice that it is okay when the provided arguments are not used. Reported-by: Andy Shevchenko Suggested-by: Jakub Kicinski Signed-off-by: Marek Szyprowski Tested-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250415075659.428549-1-m.szyprowski@samsung.com Signed-off-by: Sasha Levin

Revert "swiotlb: fix info leak with DMA_FROM_DEVICE"

2022-05-25T07:17:55Z

This reverts commit d4d975e7921079f877f828099bb8260af335508f. Upstream had a follow-up fix, revert, and a semi-reverted-revert. Instead of going through this chain which is more painful to backport, I'm just going to revert this original commit and pick the final one. Signed-off-by: Sasha Levin

swiotlb: fix info leak with DMA_FROM_DEVICE

2022-04-08T12:39:46Z

commit ddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e upstream. The problem I'm addressing was discovered by the LTP test covering cve-2018-1000204. A short description of what happens follows: 1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV and a corresponding dxferp. The peculiar thing about this is that TUR is not reading from the device. 2) In sg_start_req() the invocation of blk_rq_map_user() effectively bounces the user-space buffer. As if the device was to transfer into it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in sg_build_indirect()") we make sure this first bounce buffer is allocated with GFP_ZERO. 3) For the rest of the story we keep ignoring that we have a TUR, so the device won't touch the buffer we prepare as if the we had a DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device and the buffer allocated by SG is mapped by the function virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here scatter-gather and not scsi generics). This mapping involves bouncing via the swiotlb (we need swiotlb to do virtio in protected guest like s390 Secure Execution, or AMD SEV). 4) When the SCSI TUR is done, we first copy back the content of the second (that is swiotlb) bounce buffer (which most likely contains some previous IO data), to the first bounce buffer, which contains all zeros. Then we copy back the content of the first bounce buffer to the user-space buffer. 5) The test case detects that the buffer, which it zero-initialized, ain't all zeros and fails. One can argue that this is an swiotlb problem, because without swiotlb we leak all zeros, and the swiotlb should be transparent in a sense that it does not affect the outcome (if all other participants are well behaved). Copying the content of the original buffer into the swiotlb buffer is the only way I can think of to make swiotlb transparent in such scenarios. So let's do just that if in doubt, but allow the driver to tell us that the whole mapped buffer is going to be overwritten, in which case we can preserve the old behavior and avoid the performance impact of the extra bounce. Signed-off-by: Halil Pasic Signed-off-by: Christoph Hellwig Signed-off-by: Greg Kroah-Hartman

driver core: add a min_align_mask field to struct device_dma_parameters

2021-05-07T09:04:32Z

commit: 36950f2da1ea4cb683be174f6f581e25b2d33e71 Some devices rely on the address offset in a page to function correctly (NVMe driver as an example). These devices may use a different page size than the Linux kernel. The address offset has to be preserved upon mapping, and in order to do so, we need to record the page_offset_mask first. Signed-off-by: Jianxiong Gao Signed-off-by: Christoph Hellwig Acked-by: Greg Kroah-Hartman Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

dma-mapping: move more functions to dma-map-ops.h

2020-10-20T08:41:07Z

Due to a mismerge a bunch of prototypes that should have moved to dma-map-ops.h are still in dma-mapping.h, fix that up. Signed-off-by: Christoph Hellwig

dma-mapping: move dma-debug.h to kernel/dma/

2020-10-06T05:07:05Z

Most of dma-debug.h is not required by anything outside of kernel/dma. Move the four declarations needed by dma-mappin.h or dma-ops providers into dma-mapping.h and dma-map-ops.h, and move the remainder of the file to kernel/dma/debug.h. Signed-off-by: Christoph Hellwig

dma-mapping: split

2020-10-06T05:07:03Z

Split out all the bits that are purely for dma_map_ops implementations and related code into a new header so that they don't get pulled into all the drivers. That also means the architecture specific is not pulled in by any more, which leads to a missing includes that were pulled in by the x86 or arm versions in a few not overly portable drivers. Signed-off-by: Christoph Hellwig

dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods

2020-09-25T04:20:47Z

This will allow IOMMU drivers to allocate non-contigous memory and return a vmapped virtual address. Signed-off-by: Christoph Hellwig

dma-mapping: add a new dma_alloc_pages API

2020-09-25T04:20:47Z

This API is the equivalent of alloc_pages, except that the returned memory is guaranteed to be DMA addressable by the passed in device. The implementation will also be used to provide a more sensible replacement for DMA_ATTR_NON_CONSISTENT flag. Additionally dma_alloc_noncoherent is switched over to use dma_alloc_pages as its backend. Signed-off-by: Christoph Hellwig Acked-by: Thomas Bogendoerfer (MIPS part)

dma-mapping: remove dma_cache_sync

2020-09-25T04:20:46Z

All users are gone now, remove the API. Signed-off-by: Christoph Hellwig Acked-by: Thomas Bogendoerfer (MIPS part)