[PATCH] mm: Fix pud_alloc_track()

From: Joerg Roedel
Date: Thu Jun 04 2020 - 03:44:53 EST


From: Joerg Roedel <jroedel@xxxxxxx>

The pud_alloc_track() needs to do different checks based on whether
__ARCH_HAS_5LEVEL_HACK is defined, like it already does in
pud_alloc(). Otherwise it causes boot failures on PowerPC.

Provide the correct implementations for both possible settings of
__ARCH_HAS_5LEVEL_HACK to fix the boot problems.

Reported-by: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx>
Tested-by: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx>
Tested-by: Satheesh Rajendran <sathnaga@xxxxxxxxxxxxxxxxxx>
Fixes: d8626138009b ("mm: add functions to track page directory modifications")
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
include/asm-generic/5level-fixup.h | 5 +++++
include/linux/mm.h | 26 +++++++++++++-------------
2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
index 58046ddc08d0..afbab31fbd7e 100644
--- a/include/asm-generic/5level-fixup.h
+++ b/include/asm-generic/5level-fixup.h
@@ -17,6 +17,11 @@
((unlikely(pgd_none(*(p4d))) && __pud_alloc(mm, p4d, address)) ? \
NULL : pud_offset(p4d, address))

+#define pud_alloc_track(mm, p4d, address, mask) \
+ ((unlikely(pgd_none(*(p4d))) && \
+ (__pud_alloc(mm, p4d, address) || ({*(mask)|=PGTBL_P4D_MODIFIED;0;})))? \
+ NULL : pud_offset(p4d, address))
+
#define p4d_alloc(mm, pgd, address) (pgd)
#define p4d_alloc_track(mm, pgd, address, mask) (pgd)
#define p4d_offset(pgd, start) (pgd)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 66e0977f970a..ad3b31c5bcc3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2088,35 +2088,35 @@ static inline pud_t *pud_alloc(struct mm_struct *mm, p4d_t *p4d,
NULL : pud_offset(p4d, address);
}

-static inline p4d_t *p4d_alloc_track(struct mm_struct *mm, pgd_t *pgd,
+static inline pud_t *pud_alloc_track(struct mm_struct *mm, p4d_t *p4d,
unsigned long address,
pgtbl_mod_mask *mod_mask)
-
{
- if (unlikely(pgd_none(*pgd))) {
- if (__p4d_alloc(mm, pgd, address))
+ if (unlikely(p4d_none(*p4d))) {
+ if (__pud_alloc(mm, p4d, address))
return NULL;
- *mod_mask |= PGTBL_PGD_MODIFIED;
+ *mod_mask |= PGTBL_P4D_MODIFIED;
}

- return p4d_offset(pgd, address);
+ return pud_offset(p4d, address);
}

-#endif /* !__ARCH_HAS_5LEVEL_HACK */
-
-static inline pud_t *pud_alloc_track(struct mm_struct *mm, p4d_t *p4d,
+static inline p4d_t *p4d_alloc_track(struct mm_struct *mm, pgd_t *pgd,
unsigned long address,
pgtbl_mod_mask *mod_mask)
+
{
- if (unlikely(p4d_none(*p4d))) {
- if (__pud_alloc(mm, p4d, address))
+ if (unlikely(pgd_none(*pgd))) {
+ if (__p4d_alloc(mm, pgd, address))
return NULL;
- *mod_mask |= PGTBL_P4D_MODIFIED;
+ *mod_mask |= PGTBL_PGD_MODIFIED;
}

- return pud_offset(p4d, address);
+ return p4d_offset(pgd, address);
}

+#endif /* !__ARCH_HAS_5LEVEL_HACK */
+
static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
{
return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
--
2.26.2