ARM: LPAE: Page table maintenance for the 3-level format

This patch modifies the pgd/pmd/pte manipulation functions to support
the 3-level page table format. Since there is no need for an 'ext'
argument to cpu_set_pte_ext(), this patch conditionally defines a
different prototype for this function when CONFIG_ARM_LPAE.

The patch also introduces the L_PGD_SWAPPER flag to mark pgd entries
pointing to pmd tables pre-allocated in the swapper_pg_dir and avoid
trying to free them at run-time. This flag is 0 with the classic page
table format.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

3 files changed, 98 insertions, 0 deletions

diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
index 7418894a737f..943504f53f57 100644
--- a/arch/arm/include/asm/pgalloc.h
+++ b/arch/arm/include/asm/pgalloc.h
@@ -25,6 +25,26 @@
 #define _PAGE_USER_TABLE        (PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_USER))
 #define _PAGE_KERNEL_TABLE      (PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_KERNEL))
 
+#ifdef CONFIG_ARM_LPAE
+
+static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+        return (pmd_t *)get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
+}
+
+static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
+{
+        BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
+        free_page((unsigned long)pmd);
+}
+
+static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
+{
+        set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
+}
+
+#else   /* !CONFIG_ARM_LPAE */
+
 /*
  * Since we have only two-level page tables, these are trivial
  */
@@ -32,6 +52,8 @@
 #define pmd_free(mm, pmd)               do { } while (0)
 #define pud_populate(mm,pmd,pte)        BUG()
 
+#endif  /* CONFIG_ARM_LPAE */
+
 extern pgd_t *pgd_alloc(struct mm_struct *mm);
 extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
 
@@ -109,7 +131,9 @@ static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
 {
         pmdval_t pmdval = (pte + PTE_HWTABLE_OFF) | prot;
         pmdp[0] = __pmd(pmdval);
+#ifndef CONFIG_ARM_LPAE
         pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
+#endif
         flush_pmd_entry(pmdp);
 }
 
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 79bf0acc40db..759af70f9a0a 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -99,4 +99,57 @@
 #define L_PTE_MT_DEV_CACHED     (_AT(pteval_t, 3) << 2) /* normal inner write-back */
 #define L_PTE_MT_MASK           (_AT(pteval_t, 7) << 2)
 
+/*
+ * Software PGD flags.
+ */
+#define L_PGD_SWAPPER           (_AT(pgdval_t, 1) << 55)        /* swapper_pg_dir entry */
+
+#ifndef __ASSEMBLY__
+
+#define pud_none(pud)           (!pud_val(pud))
+#define pud_bad(pud)            (!(pud_val(pud) & 2))
+#define pud_present(pud)        (pud_val(pud))
+
+#define pud_clear(pudp)                 \
+        do {                            \
+                *pudp = __pud(0);       \
+                clean_pmd_entry(pudp);  \
+        } while (0)
+
+#define set_pud(pudp, pud)              \
+        do {                            \
+                *pudp = pud;            \
+                flush_pmd_entry(pudp);  \
+        } while (0)
+
+static inline pmd_t *pud_page_vaddr(pud_t pud)
+{
+        return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
+}
+
+/* Find an entry in the second-level page table.. */
+#define pmd_index(addr)         (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
+static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
+{
+        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
+}
+
+#define pmd_bad(pmd)            (!(pmd_val(pmd) & 2))
+
+#define copy_pmd(pmdpd,pmdps)           \
+        do {                            \
+                *pmdpd = *pmdps;        \
+                flush_pmd_entry(pmdpd); \
+        } while (0)
+
+#define pmd_clear(pmdp)                 \
+        do {                            \
+                *pmdp = __pmd(0);       \
+                clean_pmd_entry(pmdp);  \
+        } while (0)
+
+#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext)))
+
+#endif /* __ASSEMBLY__ */
+
 #endif /* _ASM_PGTABLE_3LEVEL_H */
diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 9e92cb205e65..f3628fb3d2b3 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -65,7 +65,11 @@ extern struct processor {
          * Set a possibly extended PTE.  Non-extended PTEs should
          * ignore 'ext'.
          */
+#ifdef CONFIG_ARM_LPAE
+        void (*set_pte_ext)(pte_t *ptep, pte_t pte);
+#else
         void (*set_pte_ext)(pte_t *ptep, pte_t pte, unsigned int ext);
+#endif
 
         /* Suspend/resume */
         unsigned int suspend_size;
@@ -79,7 +83,11 @@ extern void cpu_proc_fin(void);
 extern int cpu_do_idle(void);
 extern void cpu_dcache_clean_area(void *, int);
 extern void cpu_do_switch_mm(unsigned long pgd_phys, struct mm_struct *mm);
+#ifdef CONFIG_ARM_LPAE
+extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte);
+#else
 extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
+#endif
 extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
 
 /* These three are private to arch/arm/kernel/suspend.c */
@@ -107,6 +115,18 @@ extern void cpu_resume(void);
 
 #define cpu_switch_mm(pgd,mm) cpu_do_switch_mm(virt_to_phys(pgd),mm)
 
+#ifdef CONFIG_ARM_LPAE
+#define cpu_get_pgd()   \
+        ({                                              \
+                unsigned long pg, pg2;                  \
+                __asm__("mrrc   p15, 0, %0, %1, c2"     \
+                        : "=r" (pg), "=r" (pg2)         \
+                        :                               \
+                        : "cc");                        \
+                pg &= ~(PTRS_PER_PGD*sizeof(pgd_t)-1);  \
+                (pgd_t *)phys_to_virt(pg);              \
+        })
+#else
 #define cpu_get_pgd()   \
         ({                                              \
                 unsigned long pg;                       \
@@ -115,6 +135,7 @@ extern void cpu_resume(void);
                 pg &= ~0x3fff;                          \
                 (pgd_t *)phys_to_virt(pg);              \
         })
+#endif
 
 #endif