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* [patch 049/158] arm64: mm: add p?d_leaf() definitions
@ 2019-12-01  1:51 akpm
  0 siblings, 0 replies; only message in thread
From: akpm @ 2019-12-01  1:51 UTC (permalink / raw)
  To: akpm, alex, aou, ard.biesheuvel, arnd, aryabinin, benh,
	borntraeger, bp, catalin.marinas, dave.hansen, dave.jiang, davem,
	dvyukov, glider, gor, heiko.carstens, hpa, james.morse, jhogan,
	kan.liang, linux-mm, linux, luto, mark.rutland, mawilcox, mingo,
	mm-commits, mpe, n-horiguchi, palmer, paul.burton, paul.walmsley,
	paulus, peterz, ralf, shashim, steven.price, tglx, torvalds,
	vgupta, will, zong.li

From: Steven Price <steven.price@arm.com>
Subject: arm64: 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 will be provided by the
p?d_leaf() functions/macros.

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

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 at 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_leaf() as it is an
architectural restriction.

Link: http://lkml.kernel.org/r/20191028135910.33253-5-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Shiraz Hashim <shashim@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/arch/arm64/include/asm/pgtable.h~arm64-mm-add-pd_leaf-definitions
+++ a/arch/arm64/include/asm/pgtable.h
@@ -445,6 +445,7 @@ extern pgprot_t phys_mem_access_prot(str
 				 PMD_TYPE_TABLE)
 #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 				 PMD_TYPE_SECT)
+#define pmd_leaf(pmd)		pmd_sect(pmd)
 
 #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3
 static inline bool pud_sect(pud_t pud) { return false; }
@@ -529,6 +530,7 @@ 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_leaf(pud)		pud_sect(pud)
 #define pud_valid(pud)		pte_valid(pud_pte(pud))
 
 static inline void set_pud(pud_t *pudp, pud_t pud)
_


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2019-12-01  1:51 [patch 049/158] arm64: mm: add p?d_leaf() definitions akpm

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