linux-kernel - [PATCH v2 3/4] arm64: Implement page table free interfaces

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Message-Id: <1521117906-20107-4-git-send-email-cpandya@codeaurora.org>
Date:   Thu, 15 Mar 2018 18:15:05 +0530
From:   Chintan Pandya <cpandya@...eaurora.org>
To:     catalin.marinas@....com, will.deacon@....com, arnd@...db.de
Cc:     mark.rutland@....com, ard.biesheuvel@...aro.org,
        marc.zyngier@....com, james.morse@....com,
        kristina.martsenko@....com, takahiro.akashi@...aro.org,
        gregkh@...uxfoundation.org, tglx@...utronix.de,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, akpm@...ux-foundation.org,
        toshi.kani@....com, Chintan Pandya <cpandya@...eaurora.org>
Subject: [PATCH v2 3/4] arm64: Implement page table free interfaces

Implement pud_free_pmd_page() and pmd_free_pte_page().

Make sure, that they are indeed a page table before
taking them to free.

Signed-off-by: Chintan Pandya <cpandya@...eaurora.org>
---
 arch/arm64/mm/mmu.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 2dbb2c9..6f21a65 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -32,6 +32,7 @@
 #include <linux/io.h>
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
+#include <linux/hugetlb.h>
 
 #include <asm/barrier.h>
 #include <asm/cputype.h>
@@ -45,6 +46,7 @@
 #include <asm/memblock.h>
 #include <asm/mmu_context.h>
 #include <asm/ptdump.h>
+#include <asm/page.h>
 
 #define NO_BLOCK_MAPPINGS	BIT(0)
 #define NO_CONT_MAPPINGS	BIT(1)
@@ -975,10 +977,24 @@ int pmd_clear_huge(pmd_t *pmdp)
 
 int pud_free_pmd_page(pud_t *pud)
 {
-	return pud_none(*pud);
+	pmd_t *pmd;
+	int i;
+
+	pmd = __va(pud_val(*pud));
+	if (pud_val(*pud) && !pud_huge(*pud)) {
+		for (i = 0; i < PTRS_PER_PMD; i++)
+			pmd_free_pte_page(&pmd[i]);
+
+		free_page((unsigned long)pmd);
+	}
+
+	return 1;
 }
 
 int pmd_free_pte_page(pmd_t *pmd)
 {
-	return pmd_none(*pmd);
+	if (pmd_val(*pmd) && !pmd_huge(*pmd))
+		free_page((unsigned long)__va(pmd_val(*pmd)));
+
+	return 1;
 }
-- 
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