The bootloader configures a reserved memory region for framebuffer, which is protected by the IOMMU. The kernel-side driver is oblivious as of which memory region is set up by the bootloader. In such case, the IOMMU tries to reference the reserved region - which is not reserved in the kernel anymore - and it results in an unrecoverable page fault. More information about it is provided in [1]. Add support for reserved regions using iommu_dma_get_resv_regions(). For OF supported boards, this requires defining the region in the iommu-addresses property of the IOMMU owner's node. Link: https://lore.kernel.org/r/544ad69cba52a9b87447e3ac1c7fa8c3@xxxxxxxxxxx [1] Signed-off-by: Kaustabh Chakraborty <kauschluss@xxxxxxxxxxx> --- drivers/iommu/exynos-iommu.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c index b62a8f35c3e8516ead6a41f92dc7c8dc057986a8..b6edd178fe25e7c258cc82c47e9170fb4db74064 100644 --- a/drivers/iommu/exynos-iommu.c +++ b/drivers/iommu/exynos-iommu.c @@ -22,6 +22,7 @@ #include <linux/pm_runtime.h> #include <linux/slab.h> +#include "dma-iommu.h" #include "iommu-pages.h" typedef u32 sysmmu_iova_t; @@ -1479,6 +1480,7 @@ static const struct iommu_ops exynos_iommu_ops = { .device_group = generic_device_group, .probe_device = exynos_iommu_probe_device, .release_device = exynos_iommu_release_device, + .get_resv_regions = iommu_dma_get_resv_regions, .of_xlate = exynos_iommu_of_xlate, .default_domain_ops = &(const struct iommu_domain_ops) { .attach_dev = exynos_iommu_attach_device, --- base-commit: a62b7a37e6fcf4a675b1548e7c168b96ec836442 change-id: 20250629-exynos-sysmmu-resv-regions-661f2889d2d5 Best regards, -- Kaustabh Chakraborty <kauschluss@xxxxxxxxxxx>
