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arm64:mm: free the useless initial page table

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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: Zhichang Yuan <zhichang.yuan@linaro.org>
[catalin.marinas@arm.com: added BUG_ON() to catch late memblock freeing]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
zhichang.yuan 2014-12-09 07:26:47 +00:00 • committed by Catalin Marinas
commit 523d6e9fae
2 changed files with 15 additions and 3 deletions
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3
arch/arm64/include/asm/pgtable.h
View file

@ -342,9 +342,12 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
#ifdef CONFIG_ARM64_64K_PAGES #ifdef CONFIG_ARM64_64K_PAGES
#define pud_sect(pud) (0) #define pud_sect(pud) (0)
#define pud_table(pud) (1)
#else #else
#define pud_sect(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \ #define pud_sect(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \
PUD_TYPE_SECT) PUD_TYPE_SECT)
#define pud_table(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \
PUD_TYPE_TABLE)
#endif #endif
static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)

15
arch/arm64/mm/mmu.c
View file

@ -153,8 +153,14 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
* Check for previous table entries created during * Check for previous table entries created during
* boot (__create_page_tables) and flush them. * boot (__create_page_tables) and flush them.
*/ */
if (!pmd_none(old_pmd)) if (!pmd_none(old_pmd)) {
flush_tlb_all(); 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 { } else {
alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys), alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
prot, alloc); 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. * Look up the old pmd table and free it.
*/ */
if (!pud_none(old_pud)) { if (!pud_none(old_pud)) {
phys_addr_t table = __pa(pmd_offset(&old_pud, 0));
memblock_free(table, PAGE_SIZE);
flush_tlb_all(); 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);
}
} }
} else { } else {
alloc_init_pmd(mm, pud, addr, next, phys, prot, alloc); alloc_init_pmd(mm, pud, addr, next, phys, prot, alloc);