[PATCH 02/13] x86/mm: Add p?d_large() definitions

Steven Price
2019-02-15T17:03:16Z

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).

Expose p?d_large() from each architecture to detect these large mappings.

x86 already has these defined as inline functions, add a macro of the
same name so we don't end up with the generic version too.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/x86/include/asm/pgtable.h | 3 +++
arch/x86/mm/dump_pagetables.c | 2 ++
2 files changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23..3695f6acb6af 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -234,6 +234,7 @@ static inline int pmd_large(pmd_t pte)
{
return pmd_flags(pte) & _PAGE_PSE;
}
+#define pmd_large(x) pmd_large(x)

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pmd_trans_huge(pmd_t pmd)
@@ -873,6 +874,7 @@ static inline int pud_large(pud_t pud)
return 0;
}
#endif /* CONFIG_PGTABLE_LEVELS > 2 */
+#define pud_large(x) pud_large(x)

static inline unsigned long pud_index(unsigned long address)
{
@@ -1214,6 +1216,7 @@ static inline bool pgdp_maps_userspace(void *__ptr)
}

static inline int pgd_large(pgd_t pgd) { return 0; }
+#define pgd_large(x) pgd_large(x)

#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index e3cdc85ce5b6..695647dc9cb9 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -432,6 +432,7 @@ static void walk_pmd_level(struct seq_file *m, struct pg_state *st, pud_t addr,

#else
#define walk_pmd_level(m,s,a,e,p) walk_pte_level(m,s,__pmd(pud_val(a)),e,p)
+#undef pud_large
#define pud_large(a) pmd_large(__pmd(pud_val(a)))
#define pud_none(a) pmd_none(__pmd(pud_val(a)))
#endif
@@ -503,6 +504,7 @@ static void walk_p4d_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
}
}

+#undef pgd_large
#define pgd_large(a) (pgtable_l5_enabled() ? pgd_large(a) : p4d_large(__p4d(pgd_val(a))))
#define pgd_none(a) (pgtable_l5_enabled() ? pgd_none(a) : p4d_none(__p4d(pgd_val(a))))

--
2.20.1