linux-kernel - [PATCH v8 03/20] mips: mm: Add p?d

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Message-Id: <20190403141627.11664-4-steven.price@arm.com>
Date:   Wed,  3 Apr 2019 15:16:10 +0100
From:   Steven Price <steven.price@....com>
To:     linux-mm@...ck.org
Cc:     Steven Price <steven.price@....com>,
        Andy Lutomirski <luto@...nel.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
        Catalin Marinas <catalin.marinas@....com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        James Morse <james.morse@....com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Will Deacon <will.deacon@....com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Mark Rutland <Mark.Rutland@....com>,
        "Liang, Kan" <kan.liang@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paul.burton@...s.com>,
        James Hogan <jhogan@...nel.org>, linux-mips@...r.kernel.org
Subject: [PATCH v8 03/20] mips: mm: Add p?d_large() definitions

walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_large() functions/macros.

For mips, we only support large pages on 64 bit.

For 64 bit if _PAGE_HUGE is defined we can simply look for it. When not
defined we can be confident that there are no large pages in existence
and fall back on the generic implementation (added in a later patch)
which returns 0.

CC: Ralf Baechle <ralf@...ux-mips.org>
CC: Paul Burton <paul.burton@...s.com>
CC: James Hogan <jhogan@...nel.org>
CC: linux-mips@...r.kernel.org
Signed-off-by: Steven Price <steven.price@....com>
Acked-by: Paul Burton <paul.burton@...s.com>
---
 arch/mips/include/asm/pgtable-64.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index 93a9dce31f25..42162877ac62 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -273,6 +273,10 @@ static inline int pmd_present(pmd_t pmd)
 	return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 }
 
+#ifdef _PAGE_HUGE
+#define pmd_large(pmd)	((pmd_val(pmd) & _PAGE_HUGE) != 0)
+#endif
+
 static inline void pmd_clear(pmd_t *pmdp)
 {
 	pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
@@ -297,6 +301,10 @@ static inline int pud_present(pud_t pud)
 	return pud_val(pud) != (unsigned long) invalid_pmd_table;
 }
 
+#ifdef _PAGE_HUGE
+#define pud_large(pud)	((pud_val(pud) & _PAGE_HUGE) != 0)
+#endif
+
 static inline void pud_clear(pud_t *pudp)
 {
 	pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
-- 
2.20.1