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From: Nicholas Piggin <npiggin@gmail.com>
To: linux-mm@kvack.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Steven Price <steven.price@arm.com>
Subject: [PATCH 1/3] arm64: mm: Add p?d_large() definitions
Date: Sun, 23 Jun 2019 19:44:44 +1000
Message-ID: <20190623094446.28722-2-npiggin@gmail.com> (raw)
In-Reply-To: <20190623094446.28722-1-npiggin@gmail.com>

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 will be provided by the
p?d_large() functions/macros.

For arm64, we already have p?d_sect() macros which we can reuse for
p?d_large().

pud_sect() is defined as a dummy function when CONFIG_PGTABLE_LEVELS < 3
or CONFIG_ARM64_64K_PAGES is defined. However when the kernel is
configured this way then architecturally it isn't allowed to have a
large page that this level, and any code using these page walking macros
is implicitly relying on the page size/number of levels being the same as
the kernel. So it is safe to reuse this for p?d_large() as it is an
architectural restriction.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
This patch is taken from arm64 but is required if this series is not
build together with arm64 tree.

 arch/arm64/include/asm/pgtable.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index fca26759081a..0e973201bc16 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -417,6 +417,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 				 PMD_TYPE_TABLE)
 #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 				 PMD_TYPE_SECT)
+#define pmd_large(pmd)		pmd_sect(pmd)
 
 #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3
 #define pud_sect(pud)		(0)
@@ -499,6 +500,7 @@ static inline void pte_unmap(pte_t *pte) { }
 #define pud_none(pud)		(!pud_val(pud))
 #define pud_bad(pud)		(!(pud_val(pud) & PUD_TABLE_BIT))
 #define pud_present(pud)	pte_present(pud_pte(pud))
+#define pud_large(pud)		pud_sect(pud)
 #define pud_valid(pud)		pte_valid(pud_pte(pud))
 
 static inline void set_pud(pud_t *pudp, pud_t pud)
-- 
2.20.1


  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-23  9:44 [PATCH 0/3] fix vmalloc_to_page for huge vmap mappings Nicholas Piggin
2019-06-23  9:44 ` Nicholas Piggin [this message]
2019-07-01  9:27   ` [PATCH 1/3] arm64: mm: Add p?d_large() definitions Will Deacon
2019-07-01 10:03     ` Steven Price
2019-07-01 10:15       ` Will Deacon
2019-07-02  3:07         ` Nicholas Piggin
2019-07-02 10:46           ` Will Deacon
2019-06-23  9:44 ` [PATCH 2/3] powerpc/64s: Add p?d_large definitions Nicholas Piggin
2019-06-23  9:44 ` [PATCH 3/3] mm/vmalloc: fix vmalloc_to_page for huge vmap mappings Nicholas Piggin
2019-06-24  6:52   ` Anshuman Khandual
2019-06-25  0:20     ` Nicholas Piggin
2019-06-24  5:52 ` [PATCH 0/3] " Anshuman Khandual

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