Implement pud_free_pmd_page() and pmd_free_pte_page().
Implementation requires,
1) Freeing of the un-used next level page tables
2) Clearing off the current pud/pmd entry
3) Invalidate TLB which could have previously
valid but not stale entry
Signed-off-by: Chintan Pandya <cpandya@xxxxxxxxxxxxxx>
---
arch/arm64/mm/mmu.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index da98828..c70f139 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)
@@ -975,10 +976,35 @@ int pmd_clear_huge(pmd_t *pmdp)
int pud_free_pmd_page(pud_t *pud, unsigned long addr)
{
- return pud_none(*pud);
+ pmd_t *pmd;
+ int i;
+
+ pmd = __va(pud_val(*pud));
+ if (pud_val(*pud)) {
+ for (i = 0; i < PTRS_PER_PMD; i++)
+ pmd_free_pte_page(&pmd[i], addr + (i * PMD_SIZE));
+
+ free_page((unsigned long) pmd);
+ pud_clear(pud);
+ flush_tlb_kernel_range(addr, addr + PUD_SIZE);
+ }
+ return 1;
}
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
{
- return pmd_none(*pmd);
+ if (pmd_val(*pmd)) {
+ free_page((unsigned long)__va(pmd_val(*pmd)));
+
+ pmd_clear(pmd);
+ /*
+ * FIXME: __flush_tlb_pgtable(&init_mm, addr) is
+ * ideal candidate here, which exactly
+ * flushes intermediate pgtables. But,
+ * this is broken (evident from tests).
+ * So, use safe TLB op unless that is fixed.
+ */
+ flush_tlb_kernel_range(addr, addr + PMD_SIZE);
+ }
+ return 1;
}
--
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Center, Inc., is a member of Code Aurora Forum, a Linux Foundation
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