From mboxrd@z Thu Jan 1 00:00:00 1970 From: cpandya@codeaurora.org (Chintan Pandya) Date: Fri, 25 May 2018 19:58:08 +0530 Subject: [PATCH v11 3/4] arm64: Implement page table free interfaces In-Reply-To: <1527258489-30473-1-git-send-email-cpandya@codeaurora.org> References: <1527258489-30473-1-git-send-email-cpandya@codeaurora.org> Message-ID: <1527258489-30473-4-git-send-email-cpandya@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- 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 da98828..5f2da5c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -45,6 +45,7 @@ #include #include #include +#include #define NO_BLOCK_MAPPINGS BIT(0) #define NO_CONT_MAPPINGS BIT(1) @@ -973,12 +974,41 @@ 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 = __va(pmd_page_paddr(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 = __va(pud_page_paddr(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; } -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project