[PATCH v13 3/3] arm64: Implement page table free interfaces
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2018-09-20 17:25:35
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Hi Chintan, On Wed, Jun 06, 2018 at 12:31:21PM +0530, Chintan Pandya wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 8ae5d7a..65f8627 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 +978,51 @@ 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); + + /* No-op for empty entry and WARN_ON for valid entry */ + if (!pmd_present(pmd) || !pmd_table(pmd)) { + VM_WARN_ON(!pmd_table(pmd)); + return 1; + }
What's this VM_WARN_ON supposed to do here? If the pmd is 0, we trigger it all the time. Did you actually mean something like: VM_WARN_ON(!pmd_none(pmd)); or pmd_present(pmd)? Since the comment mentions empty entry, I'd rather make it explicit: if (pmd_none(pmd) || !pmd_table(pmd)) VM_WARN_ON(!pmd_none(pmd)); return 1; } Similarly for the pud_free_pmd_page(): ----------8<--------------------------
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 65f86271f02b..2662937ef879 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -986,8 +986,8 @@ int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) pmd = READ_ONCE(*pmdp); /* No-op for empty entry and WARN_ON for valid entry */ - if (!pmd_present(pmd) || !pmd_table(pmd)) { - VM_WARN_ON(!pmd_table(pmd)); + if (pmd_none(pmd) || !pmd_table(pmd)) { + VM_WARN_ON(!pmd_none(pmd)); return 1; }
@@ -1008,8 +1008,8 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) pud = READ_ONCE(*pudp); /* No-op for empty entry and WARN_ON for valid entry */ - if (!pud_present(pud) || !pud_table(pud)) { - VM_WARN_ON(!pud_table(pud)); + if (pud_none(pud) || !pud_table(pud)) { + VM_WARN_ON(!pud_none(pud)); return 1; }