On 5/24/2018 7:27 PM, Chintan Pandya wrote:
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 <[email protected]> --- arch/arm64/mm/mmu.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index da98828..17d9282 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) @@ -973,12 +974,37 @@ 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); + pmd_t *table; + pmd_t pmd; + + pmd = READ_ONCE(*pmdp); + if (pmd_present(pmd)) { + table = __va(pmd_val(pmd)); + pmd_clear(pmdp); + __flush_tlb_kernel_pgtable(addr); + pte_free_kernel(NULL, (pte_t *) 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; + pud_t pud; + int i = 0; + + pud = READ_ONCE(*pudp); + if (pud_present(pud)) { + table = __va(pud_val(pud)); + do { + pmd_free_pte_page(&table[i], addr + (i * PMD_SIZE)); + } while (i++, i < PTRS_PER_PMD);
Hi Will, Right after sending these patches, I realized that do-while condition can be made to look like what we see in ioremap/vmalloc code. I guess, that's what you suggested. So, I'll raise v11 fixing that. Any more concerns ?
+ + pud_clear(pudp); + __flush_tlb_kernel_pgtable(addr); + pmd_free(NULL, table); + } + return 1; }
Chintan -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
