Pagewalk ignores hugepd entries and walk down the tables
as if it was traditionnal entries, leading to crazy result.

Add walk_hugepd_range() and use it to walk hugepage tables.

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
 mm/pagewalk.c | 54 +++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 48 insertions(+), 6 deletions(-)

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index e81640d9f177..410a9d8f7572 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -58,6 +58,32 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, 
unsigned long end,
        return err;
 }
 
+static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
+                            unsigned long end, struct mm_walk *walk, int 
pdshift)
+{
+       int err = 0;
+#ifdef CONFIG_ARCH_HAS_HUGEPD
+       const struct mm_walk_ops *ops = walk->ops;
+       int shift = hugepd_shift(*phpd);
+       int page_size = 1 << shift;
+
+       if (addr & (page_size - 1))
+               return 0;
+
+       for (;;) {
+               pte_t *pte = hugepte_offset(*phpd, addr, pdshift);
+
+               err = ops->pte_entry(pte, addr, addr + page_size, walk);
+               if (err)
+                       break;
+               if (addr >= end - page_size)
+                       break;
+               addr += page_size;
+       }
+#endif
+       return err;
+}
+
 static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
                          struct mm_walk *walk)
 {
@@ -108,7 +134,10 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, 
unsigned long end,
                                goto again;
                }
 
-               err = walk_pte_range(pmd, addr, next, walk);
+               if (is_hugepd(__hugepd(pmd_val(*pmd))))
+                       err = walk_hugepd_range((hugepd_t *)pmd, addr, next, 
walk, PMD_SHIFT);
+               else
+                       err = walk_pte_range(pmd, addr, next, walk);
                if (err)
                        break;
        } while (pmd++, addr = next, addr != end);
@@ -157,7 +186,10 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, 
unsigned long end,
                if (pud_none(*pud))
                        goto again;
 
-               err = walk_pmd_range(pud, addr, next, walk);
+               if (is_hugepd(__hugepd(pud_val(*pud))))
+                       err = walk_hugepd_range((hugepd_t *)pud, addr, next, 
walk, PUD_SHIFT);
+               else
+                       err = walk_pmd_range(pud, addr, next, walk);
                if (err)
                        break;
        } while (pud++, addr = next, addr != end);
@@ -189,8 +221,13 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, 
unsigned long end,
                        if (err)
                                break;
                }
-               if (ops->pud_entry || ops->pmd_entry || ops->pte_entry)
-                       err = walk_pud_range(p4d, addr, next, walk);
+               if (ops->pud_entry || ops->pmd_entry || ops->pte_entry) {
+                       if (is_hugepd(__hugepd(p4d_val(*p4d))))
+                               err = walk_hugepd_range((hugepd_t *)p4d, addr, 
next, walk,
+                                                       P4D_SHIFT);
+                       else
+                               err = walk_pud_range(p4d, addr, next, walk);
+               }
                if (err)
                        break;
        } while (p4d++, addr = next, addr != end);
@@ -225,8 +262,13 @@ static int walk_pgd_range(unsigned long addr, unsigned 
long end,
                                break;
                }
                if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry ||
-                   ops->pte_entry)
-                       err = walk_p4d_range(pgd, addr, next, walk);
+                   ops->pte_entry) {
+                       if (is_hugepd(__hugepd(pgd_val(*pgd))))
+                               err = walk_hugepd_range((hugepd_t *)pgd, addr, 
next, walk,
+                                                       PGDIR_SHIFT);
+                       else
+                               err = walk_p4d_range(pgd, addr, next, walk);
+               }
                if (err)
                        break;
        } while (pgd++, addr = next, addr != end);
-- 
2.25.0

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