linux-kernel - [PATCH RFC 1/3] riscv: pgtable.h: Fixup _PAGE_CHG

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Date:   Wed, 19 May 2021 05:04:14 +0000
From:   guoren@...nel.org
To:     guoren@...nel.org, anup.patel@....com, palmerdabbelt@...gle.com,
        drew@...gleboard.org, hch@....de, wefu@...hat.com,
        lazyparser@...il.com
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-sunxi@...ts.linux.dev,
        Guo Ren <guoren@...ux.alibaba.com>,
        Arnd Bergmann <arnd@...db.de>
Subject: [PATCH RFC 1/3] riscv: pgtable.h: Fixup _PAGE_CHG_MASK usage

From: Guo Ren <guoren@...ux.alibaba.com>

'& _PAGE_CHG_MASK' should masks all attributes BITS then
'>> _PAGE_PFN_SHIFT' get the final correct PFN value.

'& _PAGE_CHG_MASK' makes the code semantics more accurate.

Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
Cc: Anup Patel <anup.patel@....com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Christoph Hellwig <hch@....de>
Cc: Drew Fustini <drew@...gleboard.org>
Cc: Palmer Dabbelt <palmerdabbelt@...gle.com>
Cc: Wei Fu <wefu@...hat.com>
Cc: Wei Wu <lazyparser@...il.com>
---
 arch/riscv/include/asm/pgtable-64.h | 8 +++++---
 arch/riscv/include/asm/pgtable.h    | 6 +++---
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
index f3b0da6..cbf9acf 100644
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -62,12 +62,14 @@ static inline void pud_clear(pud_t *pudp)
 
 static inline unsigned long pud_page_vaddr(pud_t pud)
 {
-	return (unsigned long)pfn_to_virt(pud_val(pud) >> _PAGE_PFN_SHIFT);
+	return (unsigned long)pfn_to_virt(
+		(pud_val(pud) & _PAGE_CHG_MASK) >> _PAGE_PFN_SHIFT);
 }
 
 static inline struct page *pud_page(pud_t pud)
 {
-	return pfn_to_page(pud_val(pud) >> _PAGE_PFN_SHIFT);
+	return pfn_to_page(
+		(pud_val(pud) & _PAGE_CHG_MASK) >> _PAGE_PFN_SHIFT);
 }
 
 static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)
@@ -77,7 +79,7 @@ static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)
 
 static inline unsigned long _pmd_pfn(pmd_t pmd)
 {
-	return pmd_val(pmd) >> _PAGE_PFN_SHIFT;
+	return (pmd_val(pmd) & _PAGE_CHG_MASK) >> _PAGE_PFN_SHIFT;
 }
 
 #define pmd_ERROR(e) \
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9469f46..869d6bf 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -216,12 +216,12 @@ static inline unsigned long _pgd_pfn(pgd_t pgd)
 
 static inline struct page *pmd_page(pmd_t pmd)
 {
-	return pfn_to_page(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
+	return pfn_to_page((pmd_val(pmd) & _PAGE_CHG_MASK) >> _PAGE_PFN_SHIFT);
 }
 
 static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 {
-	return (unsigned long)pfn_to_virt(pmd_val(pmd) >> _PAGE_PFN_SHIFT);
+	return (unsigned long)pfn_to_virt((pmd_val(pmd) & _PAGE_CHG_MASK) >> _PAGE_PFN_SHIFT);
 }
 
 static inline pte_t pmd_pte(pmd_t pmd)
@@ -232,7 +232,7 @@ static inline pte_t pmd_pte(pmd_t pmd)
 /* Yields the page frame number (PFN) of a page table entry */
 static inline unsigned long pte_pfn(pte_t pte)
 {
-	return (pte_val(pte) >> _PAGE_PFN_SHIFT);
+	return ((pte_val(pte) & _PAGE_CHG_MASK) >> _PAGE_PFN_SHIFT);
 }
 
 #define pte_page(x)     pfn_to_page(pte_pfn(x))
-- 
2.7.4