diff options
authorAlexander Graf <agraf@suse.de>2017-01-16 12:46:33 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2017-01-17 11:48:11 +0000
commit524dabe1c68e0bca25ce7b108099e5d89472a101 (patch)
parent49def1853334396f948dcb4cedb9347abb318df5 (diff)
arm64: Fix swiotlb fallback allocation
Commit b67a8b29df introduced logic to skip swiotlb allocation when all memory is DMA accessible anyway. While this is a great idea, __dma_alloc still calls swiotlb code unconditionally to allocate memory when there is no CMA memory available. The swiotlb code is called to ensure that we at least try get_free_pages(). Without initialization, swiotlb allocation code tries to access io_tlb_list which is NULL. That results in a stack trace like this: Unable to handle kernel NULL pointer dereference at virtual address 00000000 [...] [<ffff00000845b908>] swiotlb_tbl_map_single+0xd0/0x2b0 [<ffff00000845be94>] swiotlb_alloc_coherent+0x10c/0x198 [<ffff000008099dc0>] __dma_alloc+0x68/0x1a8 [<ffff000000a1b410>] drm_gem_cma_create+0x98/0x108 [drm] [<ffff000000abcaac>] drm_fbdev_cma_create_with_funcs+0xbc/0x368 [drm_kms_helper] [<ffff000000abcd84>] drm_fbdev_cma_create+0x2c/0x40 [drm_kms_helper] [<ffff000000abc040>] drm_fb_helper_initial_config+0x238/0x410 [drm_kms_helper] [<ffff000000abce88>] drm_fbdev_cma_init_with_funcs+0x98/0x160 [drm_kms_helper] [<ffff000000abcf90>] drm_fbdev_cma_init+0x40/0x58 [drm_kms_helper] [<ffff000000b47980>] vc4_kms_load+0x90/0xf0 [vc4] [<ffff000000b46a94>] vc4_drm_bind+0xec/0x168 [vc4] [...] Thankfully swiotlb code just learned how to not do allocations with the FORCE_NO option. This patch configures the swiotlb code to use that if we decide not to initialize the swiotlb framework. Fixes: b67a8b29df ("arm64: mm: only initialize swiotlb when necessary") Signed-off-by: Alexander Graf <agraf@suse.de> CC: Jisheng Zhang <jszhang@marvell.com> CC: Geert Uytterhoeven <geert+renesas@glider.be> CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 716d1226ba69..380ebe705093 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -404,6 +404,8 @@ void __init mem_init(void)
if (swiotlb_force == SWIOTLB_FORCE ||
max_pfn > (arm64_dma_phys_limit >> PAGE_SHIFT))
+ else
+ swiotlb_force = SWIOTLB_NO_FORCE;
set_max_mapnr(pfn_to_page(max_pfn) - mem_map);