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.
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
---
arch/arm64/mm/mmu.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index fa7351877af3..e8bf8a6300e8 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -370,6 +370,16 @@ 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);
@@ -591,7 +601,7 @@ 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);
--
2.21.0.rc0.258.g878e2cd30e-goog
