From: "zhichang.yuan" zhichang.yuan@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.yuan@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);