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Commit 1098ccd4 authored by zhichang.yuan's avatar zhichang.yuan Committed by Sami Tolvanen
Browse files

UPSTREAM: arm64:mm: free the useless initial page table 



For 64K page system, after mapping a PMD section, the corresponding initial
page table is not needed any more. That page can be freed.

Signed-off-by: default avatarZhichang Yuan <zhichang.yuan@linaro.org>
[catalin.marinas@arm.com: added BUG_ON() to catch late memblock freeing]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>

Bug: 31432001
Change-Id: Ia129c6ed670aa944e6fec9ca9c115d21468ff124
(cherry picked from commit 523d6e9fae9333a0e2a7baf4d11c8bcca544790e)
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
parent c709a705

arch/arm64/include/asm/pgtable.h

+3 −0
Original line number Diff line number Diff line
@@ -342,9 +342,12 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 


#ifdef CONFIG_ARM64_64K_PAGES

#define pud_sect(pud)		(0)

#define pud_table(pud)		(1)

#else

#define pud_sect(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \

				 PUD_TYPE_SECT)

#define pud_table(pud)		((pud_val(pud) & PUD_TYPE_MASK) == \

				 PUD_TYPE_TABLE)

#endif



static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)

arch/arm64/mm/mmu.c

+12 −3
Original line number Diff line number Diff line
@@ -153,8 +153,14 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud, 
			 * Check for previous table entries created during

			 * boot (__create_page_tables) and flush them.

			 */

			if (!pmd_none(old_pmd))

			if (!pmd_none(old_pmd)) {

				flush_tlb_all();

				if (pmd_table(old_pmd)) {

					phys_addr_t table = __pa(pte_offset_map(&old_pmd, 0));

					BUG_ON(alloc != early_alloc);

					memblock_free(table, PAGE_SIZE);

				}

			}

		} else {

			alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),

				       prot, alloc);
@@ -209,9 +215,12 @@ static void alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, 
			 * Look up the old pmd table and free it.

			 */

			if (!pud_none(old_pud)) {

				flush_tlb_all();

				if (pud_table(old_pud)) {

					phys_addr_t table = __pa(pmd_offset(&old_pud, 0));

					BUG_ON(alloc != early_alloc);

					memblock_free(table, PAGE_SIZE);

				flush_tlb_all();

				}

			}

		} else {

			alloc_init_pmd(mm, pud, addr, next, phys, prot, alloc);