Merge patch series "Fix device removal order for Apple dart iommu"

Janne Grunau <j@jannau.net> says:

Starting with v2024.10 dev_iommu_dma_unmap calls during device removal
trigger a NULL pointer dereference in the Apple dart iommu driver. The
iommu device is removed before its user. The sparsely used DM_FLAG_VITAL
flag is intended to describe this dependency. Add it to the driver.

Adding this flag is unfortunately not enough since the boot routines
except the arm one simply remove all drivers. Add and use a new function
which calls
    dm_remove_devioce_flags(DM_REMOVE_ACTIVE_ALL | DM_REMOVE_NON_VITAL);
    dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
to ensure this order dependency is head consistently.

Link: https://lore.kernel.org/r/20241123-iommu_apple_dart_ordering-v2-0-cc2ade6dde97@jannau.net

1 files changed, 3 insertions, 4 deletions

diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index 192c120a7d2..974cbfe8400 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -73,11 +73,10 @@ static void announce_and_cleanup(int fake)
 	 * Call remove function of all devices with a removal flag set.
 	 * This may be useful for last-stage operations, like cancelling
 	 * of DMA operation or releasing device internal buffers.
+	 * dm_remove_devices_active() ensures that vital devices are removed in
+	 * a second round.
 	 */
-	dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL | DM_REMOVE_NON_VITAL);
-
-	/* Remove all active vital devices next */
-	dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
+	dm_remove_devices_active();
 
 	cleanup_before_linux();
 }