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
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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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Unmap the IOVA that
dma_map_resource()returned instead of the region's physical address, so unbindingapple_sepstops warning twice in the IOMMU and stops leaking the SEP firmware mapping. Closes #591.Changes
fw_iova: Atomic<u64>toSepData, storing the return value ofdma_map_resource()next to the existingfw_mappedflag.fw_iovainstead ofregion_params.addrtodma_unmap_resource()in the unbind path.Testing
Compile-tested against
asahi-7.1.6-1with rustc 1.93.1, and runtime-tested on a MacBook Pro 16-inch 2021 (apple,j316s/apple,t6000) with thesepnode enabled:drivers/soc/apple/sep.obuilds before and after,CLIPPY=1introduces no new warnings, andrustfmt --checkpasses.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 bit.dmesg | grep -c WARNINGanddmesg | grep -c dart_unmapboth return 0, and theWtaint bit (512) stays clear.driverlink is gone afterwards, soremove()ran to completion.