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[v4,09/19] mm: Add generic p?d_large() macros

Message ID 20190306155031.4291-10-steven.price@arm.com (mailing list archive)
State New, archived
Headers show
Series Convert x86 & arm64 to use generic page walk | expand

Commit Message

Steven Price March 6, 2019, 3:50 p.m. UTC 
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(+)
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Patch

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 05e61e6c843f..f0de24100ac6 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 */