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Subject[PATCH v1 1/5] mm: pagewalk: Fix walk for hugepage tables
Date
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.leroy@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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