linux-kernel - [PATCH v10 05/22] mips: mm: Add p?d

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Date:   Wed, 31 Jul 2019 16:45:46 +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@...nel.org>, 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 v10 05/22] mips: mm: Add p?d_leaf() 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_leaf() functions/macros.

If _PAGE_HUGE is defined we can simply look for it. When not defined we
can be confident that there are no leaf 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>
---
 arch/mips/include/asm/pgtable.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 7d27194e3b45..238ca243ad31 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -627,6 +627,11 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+#ifdef _PAGE_HUGE
+#define pmd_leaf(pmd)	((pmd_val(pmd) & _PAGE_HUGE) != 0)
+#define pud_leaf(pud)	((pud_val(pud) & _PAGE_HUGE) != 0)
+#endif
+
 #define gup_fast_permitted(start, end)	(!cpu_has_dc_aliases)
 
 #include <asm-generic/pgtable.h>
-- 
2.20.1