linux-kernel - [PATCHv3 08/11] sparc64: update pmdp_invalidate to return old pmd value

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Date:   Tue, 12 Sep 2017 18:39:38 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Vineet Gupta <vgupta@...opsys.com>,
        Russell King <linux@...linux.org.uk>,
        Will Deacon <will.deacon@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Ralf Baechle <ralf@...ux-mips.org>,
        "David S. Miller" <davem@...emloft.net>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Andrea Arcangeli <aarcange@...hat.com>
Cc:     linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Nitin Gupta <nitin.m.gupta@...cle.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv3 08/11] sparc64: update pmdp_invalidate to return old pmd value

From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>

It's required to avoid loosing dirty and accessed bits.

Signed-off-by: Nitin Gupta <nitin.m.gupta@...cle.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 arch/sparc/include/asm/pgtable_64.h |  2 +-
 arch/sparc/mm/tlb.c                 | 23 ++++++++++++++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 4fefe3762083..83b06c98bb94 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -979,7 +979,7 @@ void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
 			  pmd_t *pmd);
 
 #define __HAVE_ARCH_PMDP_INVALIDATE
-extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			    pmd_t *pmdp);
 
 #define __HAVE_ARCH_PGTABLE_DEPOSIT
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index ee8066c3d96c..d36c65fc55cf 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -218,17 +218,28 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 	}
 }
 
+static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
+		unsigned long address, pmd_t *pmdp, pmd_t pmd)
+{
+	pmd_t old;
+
+	{
+		old = *pmdp;
+	} while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
+
+	return old;
+}
+
 /*
  * This routine is only called when splitting a THP
  */
-void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 		     pmd_t *pmdp)
 {
-	pmd_t entry = *pmdp;
-
-	pmd_val(entry) &= ~_PAGE_VALID;
+	pmd_t old, entry;
 
-	set_pmd_at(vma->vm_mm, address, pmdp, entry);
+	entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
+	old = pmdp_establish(vma, address, pmdp, entry);
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 
 	/*
@@ -239,6 +250,8 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 	if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
 	    !is_huge_zero_page(pmd_page(entry)))
 		(vma->vm_mm)->context.thp_pte_count--;
+
+	return old;
 }
 
 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
-- 
2.14.1