soc: apple: sep: unmap the firmware IOVA, not the physical address - #592
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soc: apple: sep: unmap the firmware IOVA, not the physical address#592brentkearney wants to merge 1 commit into
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Runtime results from the patched kernel on the
Updated the Testing section accordingly. |
load_fw_and_shmem() maps the SEP firmware region with dma_map_resource(), which returns an IOVA, but keeps only the shifted copy needed for the MSG_BOOT_IMG4 message and discards the IOVA itself. remove() then calls dma_unmap_resource() with region_params.addr, the physical address of the reserved region. The two are unrelated, so the unmap tears down page table entries that were never present, and the real mapping is leaked. On t6000 the region sits at 0x10006340000, far outside the device's DART address space, and unbinding the driver warns twice: WARNING: drivers/iommu/io-pgtable-dart.c:308 at dart_unmap_pages+0x11c/0x140 dart_unmap_pages+0x11c/0x140 apple_dart_unmap_pages+0x24/0x30 __iommu_dma_unmap+0x94/0x140 iommu_dma_unmap_phys+0xf8/0x118 ...3sep9SepDriverEE20post_unbind_callback+0x34/0x70 WARNING: drivers/iommu/dma-iommu.c:844 at __iommu_dma_unmap+0x128/0x140 __iommu_dma_unmap+0x128/0x140 iommu_dma_unmap_phys+0xf8/0x118 ...3sep9SepDriverEE20post_unbind_callback+0x34/0x70 Keep the IOVA alongside the existing fw_mapped flag and unmap that instead. Reproduced on an Apple MacBook Pro (16-inch, 2021), t6000/j316s, by enabling the sep node and unbinding the driver.
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Unbinding
apple_sepwarns twice in the IOMMU and leaks the SEP firmware mapping becauseremove()passes the region's physical address todma_unmap_resource()instead of the IOVA thatdma_map_resource()returned. This change keeps the IOVA and unmaps that.Closes #591.
Changes
fw_iova: Atomic<u64>toSepDataand store the return value ofdma_map_resource()in it next to the existingfw_mappedflag.fw_iovainstead ofregion_params.addrtodma_unmap_resource()in the unbind path.Bind and boot paths are unchanged.
Testing
asahi-7.1.6-1with rustc 1.93.1:drivers/soc/apple/sep.obuilds before and after.CLIPPY=1introduces no new warnings;rustfmt --checkpasses.apple,t6000/j316sMacBook Pro (16-inch, 2021) with thesepnode enabled,asahi-7.1.6-1plus this patch. Stock kernel:echo 396400000.sep > /sys/bus/platform/drivers/apple_sep/unbindproduces the two WARNs in apple_sep: unbinding warns twice and leaks the firmware IOMMU mapping #591 and sets theWtaint. Patched kernel: the same unbind logs nothing (dmesg | grep -c WARNINGandgrep -c dart_unmapboth 0) and theWtaint bit stays clear; the device'sdriverlink is gone afterwards.