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From: Steven Price <steven.price@arm.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Cc: "Steven Price" <steven.price@arm.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
	"Arnd Bergmann" <arnd@arndb.de>, "Borislav Petkov" <bp@alien8.de>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"James Morse" <james.morse@arm.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Will Deacon" <will@kernel.org>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	"Mark Rutland" <Mark.Rutland@arm.com>,
	"Liang, Kan" <kan.liang@linux.intel.com>,
	"Mark Rutland" <mark.rutland@arm.com>
Subject: [PATCH v15 01/23] mm: Add generic p?d_leaf() macros
Date: Fri,  1 Nov 2019 14:09:20 +0000
Message-ID: <20191101140942.51554-2-steven.price@arm.com> (raw)
In-Reply-To: <20191101140942.51554-1-steven.price@arm.com>

Exposing the pud/pgd levels of the page tables to walk_page_range() means
we may come across the exotic large mappings that come with large areas
of contiguous memory (such as the kernel's linear map).

For architectures that don't provide all p?d_leaf() macros, provide
generic do nothing default that are suitable where there cannot be leaf
pages at that level. Futher patches will add implementations for
individual architectures.

The name p?d_leaf() is chosen to minimize the confusion with existing
uses of "large" pages and "huge" pages which do not necessary mean that
the entry is a leaf (for example it may be a set of contiguous entries
that only take 1 TLB slot). For the purpose of walking the page tables
we don't need to know how it will be represented in the TLB, but we do
need to know for sure if it is a leaf of the tree.

Signed-off-by: Steven Price <steven.price@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
---
 include/asm-generic/pgtable.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 818691846c90..7f9eced287b7 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1187,4 +1187,24 @@ static inline bool arch_has_pfn_modify_check(void)
 #define mm_pmd_folded(mm)	__is_defined(__PAGETABLE_PMD_FOLDED)
 #endif
 
+/*
+ * p?d_leaf() - true if this entry is a final mapping to a physical address.
+ * This differs from p?d_huge() by the fact that they are always available (if
+ * the architecture supports large pages at the appropriate level) even
+ * if CONFIG_HUGETLB_PAGE is not defined.
+ * Only meaningful when called on a valid entry.
+ */
+#ifndef pgd_leaf
+#define pgd_leaf(x)	0
+#endif
+#ifndef p4d_leaf
+#define p4d_leaf(x)	0
+#endif
+#ifndef pud_leaf
+#define pud_leaf(x)	0
+#endif
+#ifndef pmd_leaf
+#define pmd_leaf(x)	0
+#endif
+
 #endif /* _ASM_GENERIC_PGTABLE_H */
-- 
2.20.1



  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-01 14:09 [PATCH v15 00/23] Generic page walk and ptdump Steven Price
2019-11-01 14:09 ` Steven Price [this message]
2019-11-01 14:09 ` [PATCH v15 02/23] arc: mm: Add p?d_leaf() definitions Steven Price
2019-11-01 14:09 ` [PATCH v15 03/23] arm: " Steven Price
2019-11-01 14:09 ` [PATCH v15 04/23] arm64: " Steven Price
2019-11-01 14:09 ` [PATCH v15 05/23] mips: " Steven Price
2019-11-01 14:09 ` [PATCH v15 06/23] powerpc: " Steven Price
2019-11-01 14:09 ` [PATCH v15 07/23] riscv: " Steven Price
2019-11-01 14:09 ` [PATCH v15 08/23] s390: " Steven Price
2019-11-01 14:09 ` [PATCH v15 09/23] sparc: " Steven Price
2019-11-01 14:09 ` [PATCH v15 10/23] x86: " Steven Price
2019-11-01 14:09 ` [PATCH v15 11/23] mm: pagewalk: Add p4d_entry() and pgd_entry() Steven Price
2019-11-01 14:09 ` [PATCH v15 12/23] mm: pagewalk: Allow walking without vma Steven Price
2019-11-01 14:09 ` [PATCH v15 13/23] mm: pagewalk: Add test_p?d callbacks Steven Price
2019-11-01 14:09 ` [PATCH v15 14/23] mm: pagewalk: Add 'depth' parameter to pte_hole Steven Price
2019-11-01 14:09 ` [PATCH v15 15/23] x86: mm: Point to struct seq_file from struct pg_state Steven Price
2019-11-01 14:09 ` [PATCH v15 16/23] x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct Steven Price
2019-11-01 14:09 ` [PATCH v15 17/23] x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct Steven Price
2019-11-01 14:09 ` [PATCH v15 18/23] x86: mm: Convert ptdump_walk_pgd_level_core() " Steven Price
2019-11-01 14:09 ` [PATCH v15 19/23] mm: Add generic ptdump Steven Price
2019-11-01 14:09 ` [PATCH v15 20/23] x86: mm: Convert dump_pagetables to use walk_page_range Steven Price
2019-11-01 14:09 ` [PATCH v15 21/23] arm64: mm: Convert mm/dump.c to use walk_page_range() Steven Price
2019-11-01 14:09 ` [PATCH v15 22/23] arm64: mm: Display non-present entries in ptdump Steven Price
2019-11-01 14:09 ` [PATCH v15 23/23] mm: ptdump: Reduce level numbers by 1 in note_page() Steven Price
2019-11-04 19:35 ` [PATCH v15 00/23] Generic page walk and ptdump Qian Cai
2019-11-06 13:31   ` Qian Cai
2019-11-06 15:05     ` Steven Price
2019-12-03 11:02       ` David Hildenbrand
2019-12-04 14:54         ` Qian Cai
2019-12-04 14:56           ` David Hildenbrand
2019-12-04 16:32             ` Steven Price
2019-12-04 17:51               ` Thomas Hellstrom
2019-12-05 13:15               ` Qian Cai
2019-12-05 14:32                 ` Thomas Hellstrom
2019-12-05 14:38                   ` Qian Cai

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