[PATCHv3 5/7] x86/mm: Add basic defines/helpers for CONFIG_X86_5LEVEL

[Kirill A. Shutemov]

Extends pagetable headers to support new paging mode.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 arch/x86/include/asm/pgtable_64.h       | 11 +++++++++++
 arch/x86/include/asm/pgtable_64_types.h | 20 ++++++++++++++++++++
 arch/x86/include/asm/pgtable_types.h    | 10 +++++++++-
 arch/x86/mm/pgtable.c                   | 32 +++++++++++++++++++++++++++++++-
 4 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64.h 
b/arch/x86/include/asm/pgtable_64.h
index 0593a1ae7573..12ea31274eb6 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -35,6 +35,13 @@ extern void paging_init(void);
 #define pud_ERROR(e)                                   \
        pr_err("%s:%d: bad pud %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), pud_val(e))
+
+#if CONFIG_PGTABLE_LEVELS >= 5
+#define p4d_ERROR(e)                                   \
+       pr_err("%s:%d: bad p4d %p(%016lx)\n",           \
+              __FILE__, __LINE__, &(e), p4d_val(e))
+#endif
+
 #define pgd_ERROR(e)                                   \
        pr_err("%s:%d: bad pgd %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), pgd_val(e))
@@ -128,7 +135,11 @@ static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d)
 
 static inline void native_p4d_clear(p4d_t *p4d)
 {
+#ifdef CONFIG_X86_5LEVEL
+       native_set_p4d(p4d, native_make_p4d(0));
+#else
        native_set_p4d(p4d, (p4d_t) { .pgd = native_make_pgd(0)});
+#endif
 }
 
 static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
diff --git a/arch/x86/include/asm/pgtable_64_types.h 
b/arch/x86/include/asm/pgtable_64_types.h
index 4edc97917382..adc3e7b107ee 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -23,12 +23,32 @@ typedef struct { pteval_t pte; } pte_t;
 
 #define SHARED_KERNEL_PMD      0
 
+#ifdef CONFIG_X86_5LEVEL
+
+/*
+ * PGDIR_SHIFT determines what a top-level page table entry can map
+ */
+#define PGDIR_SHIFT    48
+#define PTRS_PER_PGD   512
+
+/*
+ * 4th level page in 5-level paging case
+ */
+#define P4D_SHIFT      39
+#define PTRS_PER_P4D   512
+#define P4D_SIZE       (_AC(1, UL) << P4D_SHIFT)
+#define P4D_MASK       (~(P4D_SIZE - 1))
+
+#else /* CONFIG_X86_5LEVEL */
+
 /*
  * PGDIR_SHIFT determines what a top-level page table entry can map
  */
 #define PGDIR_SHIFT    39
 #define PTRS_PER_PGD   512
 
+#endif /* CONFIG_X86_5LEVEL */
+
 /*
  * 3rd level page
  */
diff --git a/arch/x86/include/asm/pgtable_types.h 
b/arch/x86/include/asm/pgtable_types.h
index 4930afe9df0a..bf9638e1ee42 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -273,9 +273,17 @@ static inline pgdval_t pgd_flags(pgd_t pgd)
 }
 
 #if CONFIG_PGTABLE_LEVELS > 4
+typedef struct { p4dval_t p4d; } p4d_t;
 
-#error FIXME
+static inline p4d_t native_make_p4d(pudval_t val)
+{
+       return (p4d_t) { val };
+}
 
+static inline p4dval_t native_p4d_val(p4d_t p4d)
+{
+       return p4d.p4d;
+}
 #else
 #include <asm-generic/pgtable-nop4d.h>
 
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 38b6daf72deb..508a708eb9a6 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -81,6 +81,14 @@ void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
        paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
        tlb_remove_page(tlb, virt_to_page(pud));
 }
+
+#if CONFIG_PGTABLE_LEVELS > 4
+void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
+{
+       paravirt_release_p4d(__pa(p4d) >> PAGE_SHIFT);
+       tlb_remove_page(tlb, virt_to_page(p4d));
+}
+#endif /* CONFIG_PGTABLE_LEVELS > 4 */
 #endif /* CONFIG_PGTABLE_LEVELS > 3 */
 #endif /* CONFIG_PGTABLE_LEVELS > 2 */
 
@@ -120,7 +128,7 @@ static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
           references from swapper_pg_dir. */
        if (CONFIG_PGTABLE_LEVELS == 2 ||
            (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) ||
-           CONFIG_PGTABLE_LEVELS == 4) {
+           CONFIG_PGTABLE_LEVELS >= 4) {
                clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
                                swapper_pg_dir + KERNEL_PGD_BOUNDARY,
                                KERNEL_PGD_PTRS);
@@ -582,6 +590,28 @@ void native_set_fixmap(enum fixed_addresses idx, 
phys_addr_t phys,
 }
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+#ifdef CONFIG_X86_5LEVEL
+/**
+ * p4d_set_huge - setup kernel P4D mapping
+ *
+ * No 512GB pages yet -- always return 0
+ */
+int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
+{
+       return 0;
+}
+
+/**
+ * p4d_clear_huge - clear kernel P4D mapping when it is set
+ *
+ * No 512GB pages yet -- always return 0
+ */
+int p4d_clear_huge(p4d_t *p4d)
+{
+       return 0;
+}
+#endif
+
 /**
  * pud_set_huge - setup kernel PUD mapping
  *
-- 
2.11.0