From: "zhichang.yuan" <zhichang.y...@linaro.org>
For 64K page system, after mapping a PMD section, the corresponding initial
page table is not needed any more. That page can be freed.
Changes since v1:
* make consistent code between alloc_init_pmd and alloc_init_pud;
* flush the TLB before the unused page table is freed;
Signed-off-by: Zhichang Yuan <zhichang.y...@linaro.org>
---
arch/arm64/include/asm/pgtable.h | 3 +++
arch/arm64/mm/mmu.c | 15 ++++++++++++---
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 41a43bf..8a135b6 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -337,9 +337,12 @@ 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)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f4f8b50..515f75b 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -191,8 +191,14 @@ static void __init alloc_init_pmd(pud_t *pud, unsigned
long addr,
* 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));
+
+ memblock_free(table, PAGE_SIZE);
+ }
+ }
} else {
alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
prot_pte);
@@ -234,9 +240,12 @@ static void __init alloc_init_pud(pgd_t *pgd, unsigned
long addr,
* Look up the old pmd table and free it.
*/
if (!pud_none(old_pud)) {
- phys_addr_t table = __pa(pmd_offset(&old_pud,
0));
- memblock_free(table, PAGE_SIZE);
flush_tlb_all();
+ if (pud_table(old_pud)) {
+ phys_addr_t table =
__pa(pmd_offset(&old_pud, 0));
+
+ memblock_free(table, PAGE_SIZE);
+ }
}
} else {
alloc_init_pmd(pud, addr, next, phys, map_io);
--
1.7.9.5
--
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