From: Ard Biesheuvel Date: Fri, 29 May 2026 15:01:55 +0000 (+0200) Subject: arm64: mm: Preserve existing table mappings when mapping DRAM X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=a64293e993f6ee6b5dcf107d3a7aa8c6ccca029c;p=thirdparty%2Flinux.git arm64: mm: Preserve existing table mappings when mapping DRAM Instead of blindly overwriting an existing table entry when mapping DRAM regions, take care not to replace a pre-existing table entry with a block entry. This permits the logic of mapping the kernel's linear alias to be simplified in a subsequent patch. Reviewed-by: Ryan Roberts Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon --- diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 3b302a0e8f345..1db44adc87170 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -256,7 +256,8 @@ static int init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, /* try section mapping first */ if (((addr | next | phys) & ~PMD_MASK) == 0 && - (flags & NO_BLOCK_MAPPINGS) == 0) { + (flags & NO_BLOCK_MAPPINGS) == 0 && + !pmd_table(old_pmd)) { WARN_ON(!pmd_set_huge(pmdp, phys, prot)); /* @@ -379,7 +380,8 @@ static int alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, */ if (pud_sect_supported() && ((addr | next | phys) & ~PUD_MASK) == 0 && - (flags & NO_BLOCK_MAPPINGS) == 0) { + (flags & NO_BLOCK_MAPPINGS) == 0 && + !pud_table(old_pud)) { WARN_ON(!pud_set_huge(pudp, phys, prot)); /*