[PATCH v8 10/20] mm: Add generic p?d_large() macros

From: Steven Price <steven.price@arm.com>
To: 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.deacon@arm.com>,
	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>,
	"Andrew Morton" <akpm@linux-foundation.org>
Subject: [PATCH v8 10/20] mm: Add generic p?d_large() macros
Date: Wed,  3 Apr 2019 15:16:17 +0100	[thread overview]
Message-ID: <20190403141627.11664-11-steven.price@arm.com> (raw)
In-Reply-To: <20190403141627.11664-1-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 p?d_large() macros, provide generic
does nothing defaults.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 include/asm-generic/pgtable.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index fa782fba51ee..9c5d0f73db67 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1186,4 +1186,23 @@ static inline bool arch_has_pfn_modify_check(void)
 #define mm_pmd_folded(mm)	__is_defined(__PAGETABLE_PMD_FOLDED)
 #endif
 
+/*
+ * p?d_large() - 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.
+ */
+#ifndef pgd_large
+#define pgd_large(x)	0
+#endif
+#ifndef p4d_large
+#define p4d_large(x)	0
+#endif
+#ifndef pud_large
+#define pud_large(x)	0
+#endif
+#ifndef pmd_large
+#define pmd_large(x)	0
+#endif
+
 #endif /* _ASM_GENERIC_PGTABLE_H */
-- 
2.20.1

