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Commit 0a5bb657 authored by Shiraz Hashim's avatar Shiraz Hashim Committed by Jeevan Shriram
Browse files

arm64: mmu: dma remap fail with 1GB block mapping 



The provision to map 1GB block, gives a problem during
dma_contiguous_remap when it attempts to remaps the dma
buffers into 4K. During this attempt to remap dma buffers
it overwrites pgd mapping for 1G block, thus leaving an
unmapped hole.

Managing remapping of dma regions with 1G block mapping is
difficult hence avoid mapping 1G block and switch to
SECTION_SIZE mapping (2MB) when memory region overlaps
with dma buffers range.

Change-Id: I2aa4119b3aeb328a2b95cf22656d2ec36012716f
Signed-off-by: default avatarShiraz Hashim <shashim@codeaurora.org>
parent 8df0f9ec

arch/arm64/mm/mmu.c

+18 −0
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ u64 idmap_t0sz = TCR_T0SZ(VA_BITS); 
struct page *empty_zero_page;

EXPORT_SYMBOL(empty_zero_page);



static bool __init dma_overlap(phys_addr_t start, phys_addr_t end);



pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,

			      unsigned long size, pgprot_t vma_prot)

{
@@ -216,6 +218,7 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, 
		 * For 4K granule only, attempt to put down a 1GB block

		 */

		if (use_1G_block(addr, next, phys) &&

			!dma_overlap(phys, phys + next - addr) &&

			!IS_ENABLED(CONFIG_FORCE_PAGES)) {

			pud_t old_pud = *pud;

			set_pud(pud, __pud(phys |
@@ -346,6 +349,21 @@ void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) 
	dma_mmu_remap_num++;

}



static bool __init dma_overlap(phys_addr_t start, phys_addr_t end)

{

	int i;



	for (i = 0; i < dma_mmu_remap_num; i++) {

		phys_addr_t dma_base = dma_mmu_remap[i].base;

		phys_addr_t dma_end = dma_mmu_remap[i].base +

			dma_mmu_remap[i].size;



		if ((dma_base < end) && (dma_end > start))

			return true;

	}

	return false;

}



static void __init dma_contiguous_remap(void)

{

	int i;