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@xxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
---
v3:
- Rebased on next-20210624 (no change since v2)
- Added Steven's Reviewed-by
- Sent as standalone for merge via mm
v2:
- Add a guard for NULL ops->pte_entry
- Take mm->page_table_lock when walking hugepage table, as suggested by follow_huge_pd()
---
mm/pagewalk.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 53 insertions(+), 5 deletions(-)
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index e81640d9f177..9b3db11a4d1d 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -58,6 +58,45 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
return err;
}
+#ifdef CONFIG_ARCH_HAS_HUGEPD
+static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
+ unsigned long end, struct mm_walk *walk, int pdshift)
+{
+ int err = 0;
+ const struct mm_walk_ops *ops = walk->ops;
+ int shift = hugepd_shift(*phpd);
+ int page_size = 1 << shift;
+
+ if (!ops->pte_entry)
+ return 0;
+
+ if (addr & (page_size - 1))
+ return 0;
+
+ for (;;) {
+ pte_t *pte;
+
+ spin_lock(&walk->mm->page_table_lock);
+ pte = hugepte_offset(*phpd, addr, pdshift);
+ err = ops->pte_entry(pte, addr, addr + page_size, walk);
+ spin_unlock(&walk->mm->page_table_lock);
+
+ if (err)
+ break;
+ if (addr >= end - page_size)
+ break;
+ addr += page_size;
+ }
+ return err;
+}
+#else
+static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
+ unsigned long end, struct mm_walk *walk, int pdshift)
+{
+ return 0;
+}
+#endif
+
static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
@@ -108,7 +147,10 @@ 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 +199,10 @@ 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);
@@ -189,7 +234,9 @@ 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)
+ if (is_hugepd(__hugepd(p4d_val(*p4d))))
+ err = walk_hugepd_range((hugepd_t *)p4d, addr, next, walk, P4D_SHIFT);
+ else if (ops->pud_entry || ops->pmd_entry || ops->pte_entry)
err = walk_pud_range(p4d, addr, next, walk);
if (err)
break;
@@ -224,8 +271,9 @@ static int walk_pgd_range(unsigned long addr, unsigned long end,
if (err)
break;
}
- if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry ||
- ops->pte_entry)
+ if (is_hugepd(__hugepd(pgd_val(*pgd))))
+ err = walk_hugepd_range((hugepd_t *)pgd, addr, next, walk, PGDIR_SHIFT);
+ else if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || ops->pte_entry)
err = walk_p4d_range(pgd, addr, next, walk);
if (err)
break;
--
2.25.0
