[PATCH v3 24/34] mm: Add generic p?d_large() macros

[Steven Price]

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).

Where levels are folded we need to provide the appropriate stub
implementation of p?d_large().

For x86 move the existing definitions of p?d_large() so that they are
only defined when the corresponding levels are not folded.

Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
 arch/x86/include/asm/pgtable.h           | 21 ++++++++-------------
 include/asm-generic/4level-fixup.h       |  1 +
 include/asm-generic/5level-fixup.h       |  1 +
 include/asm-generic/pgtable-nop4d-hack.h |  1 +
 include/asm-generic/pgtable-nop4d.h      |  1 +
 include/asm-generic/pgtable-nopmd.h      |  1 +
 include/asm-generic/pgtable-nopud.h      |  1 +
 7 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23..1b854c64cc7d 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -222,12 +222,6 @@ static inline unsigned long pgd_pfn(pgd_t pgd)
 	return (pgd_val(pgd) & PTE_PFN_MASK) >> PAGE_SHIFT;
 }
 
-static inline int p4d_large(p4d_t p4d)
-{
-	/* No 512 GiB pages yet */
-	return 0;
-}
-
 #define pte_page(pte)	pfn_to_page(pte_pfn(pte))
 
 static inline int pmd_large(pmd_t pte)
@@ -867,11 +861,6 @@ static inline int pud_bad(pud_t pud)
 {
 	return (pud_flags(pud) & ~(_KERNPG_TABLE | _PAGE_USER)) != 0;
 }
-#else
-static inline int pud_large(pud_t pud)
-{
-	return 0;
-}
 #endif	/* CONFIG_PGTABLE_LEVELS > 2 */
 
 static inline unsigned long pud_index(unsigned long address)
@@ -890,6 +879,12 @@ static inline int p4d_present(p4d_t p4d)
 	return p4d_flags(p4d) & _PAGE_PRESENT;
 }
 
+static inline int p4d_large(p4d_t p4d)
+{
+	/* No 512 GiB pages yet */
+	return 0;
+}
+
 static inline unsigned long p4d_page_vaddr(p4d_t p4d)
 {
 	return (unsigned long)__va(p4d_val(p4d) & p4d_pfn_mask(p4d));
@@ -931,6 +926,8 @@ static inline int pgd_present(pgd_t pgd)
 	return pgd_flags(pgd) & _PAGE_PRESENT;
 }
 
+static inline int pgd_large(pgd_t pgd) { return 0; }
+
 static inline unsigned long pgd_page_vaddr(pgd_t pgd)
 {
 	return (unsigned long)__va((unsigned long)pgd_val(pgd) & PTE_PFN_MASK);
@@ -1213,8 +1210,6 @@ static inline bool pgdp_maps_userspace(void *__ptr)
 	return (((ptr & ~PAGE_MASK) / sizeof(pgd_t)) < PGD_KERNEL_START);
 }
 
-static inline int pgd_large(pgd_t pgd) { return 0; }
-
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
 /*
  * All top-level PAGE_TABLE_ISOLATION page tables are order-1 pages
diff --git a/include/asm-generic/4level-fixup.h b/include/asm-generic/4level-fixup.h
index e3667c9a33a5..3cc65a4dd093 100644
--- a/include/asm-generic/4level-fixup.h
+++ b/include/asm-generic/4level-fixup.h
@@ -20,6 +20,7 @@
 #define pud_none(pud)			0
 #define pud_bad(pud)			0
 #define pud_present(pud)		1
+#define pud_large(pud)			0
 #define pud_ERROR(pud)			do { } while (0)
 #define pud_clear(pud)			pgd_clear(pud)
 #define pud_val(pud)			pgd_val(pud)
diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
index bb6cb347018c..c4377db09a4f 100644
--- a/include/asm-generic/5level-fixup.h
+++ b/include/asm-generic/5level-fixup.h
@@ -22,6 +22,7 @@
 #define p4d_none(p4d)			0
 #define p4d_bad(p4d)			0
 #define p4d_present(p4d)		1
+#define p4d_large(p4d)			0
 #define p4d_ERROR(p4d)			do { } while (0)
 #define p4d_clear(p4d)			pgd_clear(p4d)
 #define p4d_val(p4d)			pgd_val(p4d)
diff --git a/include/asm-generic/pgtable-nop4d-hack.h b/include/asm-generic/pgtable-nop4d-hack.h
index 829bdb0d6327..d3967560d123 100644
--- a/include/asm-generic/pgtable-nop4d-hack.h
+++ b/include/asm-generic/pgtable-nop4d-hack.h
@@ -27,6 +27,7 @@ typedef struct { pgd_t pgd; } pud_t;
 static inline int pgd_none(pgd_t pgd)		{ return 0; }
 static inline int pgd_bad(pgd_t pgd)		{ return 0; }
 static inline int pgd_present(pgd_t pgd)	{ return 1; }
+static inline int pgd_large(pgd_t pgd)		{ return 0; }
 static inline void pgd_clear(pgd_t *pgd)	{ }
 #define pud_ERROR(pud)				(pgd_ERROR((pud).pgd))
 
diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
index aebab905e6cd..5d5dde24a8ca 100644
--- a/include/asm-generic/pgtable-nop4d.h
+++ b/include/asm-generic/pgtable-nop4d.h
@@ -22,6 +22,7 @@ typedef struct { pgd_t pgd; } p4d_t;
 static inline int pgd_none(pgd_t pgd)		{ return 0; }
 static inline int pgd_bad(pgd_t pgd)		{ return 0; }
 static inline int pgd_present(pgd_t pgd)	{ return 1; }
+static inline int pgd_large(pgd_t pgd)		{ return 0; }
 static inline void pgd_clear(pgd_t *pgd)	{ }
 #define p4d_ERROR(p4d)				(pgd_ERROR((p4d).pgd))
 
diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h
index b85b8271a73d..beeb8f375d4d 100644
--- a/include/asm-generic/pgtable-nopmd.h
+++ b/include/asm-generic/pgtable-nopmd.h
@@ -30,6 +30,7 @@ typedef struct { pud_t pud; } pmd_t;
 static inline int pud_none(pud_t pud)		{ return 0; }
 static inline int pud_bad(pud_t pud)		{ return 0; }
 static inline int pud_present(pud_t pud)	{ return 1; }
+static inline int pud_large(pud_t pud)		{ return 0; }
 static inline void pud_clear(pud_t *pud)	{ }
 #define pmd_ERROR(pmd)				(pud_ERROR((pmd).pud))
 
diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h
index c77a1d301155..b3ba496965d3 100644
--- a/include/asm-generic/pgtable-nopud.h
+++ b/include/asm-generic/pgtable-nopud.h
@@ -31,6 +31,7 @@ typedef struct { p4d_t p4d; } pud_t;
 static inline int p4d_none(p4d_t p4d)		{ return 0; }
 static inline int p4d_bad(p4d_t p4d)		{ return 0; }
 static inline int p4d_present(p4d_t p4d)	{ return 1; }
+static inline int p4d_large(p4d_t p4d)		{ return 0; }
 static inline void p4d_clear(p4d_t *p4d)	{ }
 #define pud_ERROR(pud)				(p4d_ERROR((pud).p4d))
 
-- 
2.20.1