arm64: Fix memblock current_limit with 64K pages and 48-bit VA (3dec0fe4) · Commits · 戴 / test

With 48-bit VA space, the 64K page configuration uses 3 levels instead of 2 and PUD_SIZE != PMD_SIZE. Since with 64K pages we only cover PMD_SIZE with the initial swapper_pg_dir populated in head.S, the memblock current_limit needs to be set accordingly in map_mem() to avoid allocating unmapped memory. The memblock current_limit is progressively increased as more blocks are mapped. Signed-off-by:

Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/mmu.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -297,10 +297,14 @@ static void __init map_mem(void)
		* create_mapping requires puds, pmds and ptes to be allocated from
		* memory addressable from the initial direct kernel mapping.
		*
		* The initial direct kernel mapping, located at swapper_pg_dir,
		* gives us PUD_SIZE memory starting from PHYS_OFFSET (which must be
		* aligned to 2MB as per Documentation/arm64/booting.txt).
		* The initial direct kernel mapping, located at swapper_pg_dir, gives
		* us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
		* PHYS_OFFSET (which must be aligned to 2MB as per
		* Documentation/arm64/booting.txt).
		*/
		if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
		limit = PHYS_OFFSET + PMD_SIZE;
		else
		limit = PHYS_OFFSET + PUD_SIZE;
		memblock_set_current_limit(limit);

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