[PATCH v12 4/5] arm64: Implement page table free interfaces
From: Chintan Pandya <hidden>
Date: 2018-06-01 12:40:00
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Implement pud_free_pmd_page() and pmd_free_pte_page().
Implementation requires,
1) Clearing off the current pud/pmd entry
2) Invalidate TLB which could have previously
valid but not stale entry
3) Freeing of the un-used next level page tables
Signed-off-by: Chintan Pandya <redacted>
---
arch/arm64/mm/mmu.c | 38 ++++++++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 8ae5d7a..6e7e16c 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -45,6 +45,7 @@ #include <asm/memblock.h> #include <asm/mmu_context.h> #include <asm/ptdump.h> +#include <asm/tlbflush.h> #define NO_BLOCK_MAPPINGS BIT(0) #define NO_CONT_MAPPINGS BIT(1)
@@ -977,12 +978,41 @@ int pmd_clear_huge(pmd_t *pmdp) return 1; } -int pud_free_pmd_page(pud_t *pud, unsigned long addr) +int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) { - return pud_none(*pud); + pte_t *table; + pmd_t pmd; + + pmd = READ_ONCE(*pmdp); + if (pmd_present(pmd)) { + table = pmd_page_vaddr(pmd); + pmd_clear(pmdp); + __flush_tlb_kernel_pgtable(addr); + pte_free_kernel(NULL, table); + } + return 1; } -int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) +int pud_free_pmd_page(pud_t *pudp, unsigned long addr) { - return pmd_none(*pmd); + pmd_t *table; + pmd_t *entry; + pud_t pud; + unsigned long next, end; + + pud = READ_ONCE(*pudp); + if (pud_present(pud)) { + table = pud_page_vaddr(pud); + entry = table; + next = addr; + end = addr + PUD_SIZE; + do { + pmd_free_pte_page(entry, next); + } while (entry++, next += PMD_SIZE, next != end); + + pud_clear(pudp); + __flush_tlb_kernel_pgtable(addr); + pmd_free(NULL, table); + } + return 1; }
--
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