Commit 369aaab8 authored by Yu Zhao's avatar Yu Zhao Committed by Will Deacon
Browse files

arm64: mm: don't call page table ctors for init_mm 



init_mm doesn't require page table lock to be initialized at
any level. Add a separate page table allocator for it, and the
new one skips page table ctors.

The ctors allocate memory when ALLOC_SPLIT_PTLOCKS is set. Not
calling them avoids memory leak in case we call pte_free_kernel()
on init_mm.

Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarYu Zhao <yuzhao@google.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 90292aca

arch/arm64/mm/mmu.c

+13 −2
Original line number Diff line number Diff line
@@ -371,6 +371,16 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 
	} while (pgdp++, addr = next, addr != end);

}



static phys_addr_t pgd_kernel_pgtable_alloc(int shift)

{

	void *ptr = (void *)__get_free_page(PGALLOC_GFP);

	BUG_ON(!ptr);



	/* Ensure the zeroed page is visible to the page table walker */

	dsb(ishst);

	return __pa(ptr);

}



static phys_addr_t pgd_pgtable_alloc(int shift)

{

	void *ptr = (void *)__get_free_page(PGALLOC_GFP);
@@ -595,7 +605,7 @@ static int __init map_entry_trampoline(void) 
	/* Map only the text into the trampoline page table */

	memset(tramp_pg_dir, 0, PGD_SIZE);

	__create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,

			     prot, pgd_pgtable_alloc, 0);

			     prot, pgd_kernel_pgtable_alloc, 0);



	/* Map both the text and data into the kernel page table */

	__set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
@@ -1067,7 +1077,8 @@ int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, 
		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;



	__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),

			     size, PAGE_KERNEL, pgd_pgtable_alloc, flags);

			     size, PAGE_KERNEL, pgd_kernel_pgtable_alloc,

			     flags);



	return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,

			   altmap, want_memblock);

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