diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-12-18 16:24:34 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-01-20 13:48:30 +0000 |
| commit | 56dd47098abe1fdde598a8d8b7c04d775506f456 (patch) | |
| tree | 5eda8a531087c9c068702aa426db8479a77147f8 /arch/arm | |
| parent | f8a85f1164a33e3eb5b421b137ced793ed53ee33 (diff) | |
ARM: make_coherent: fix problems with highpte, part 1
update_mmu_cache() is called with a page table already mapped. We
call make_coherent(), which then calls adjust_pte() which wants to
map other page tables. This causes kmap_atomic() to BUG() because
the slot its trying to use is already taken.
Since do_adjust_pte() modifies the page tables, we are also missing
any form of locking, so we're risking corrupting the page tables.
Fix this by using pte_offset_map_nested(), and taking the pte page
table lock around do_adjust_pte().
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mm/fault-armv.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c index 7a8efe1b37d..8e9bc517132 100644 --- a/arch/arm/mm/fault-armv.c +++ b/arch/arm/mm/fault-armv.c @@ -67,6 +67,7 @@ static int do_adjust_pte(struct vm_area_struct *vma, unsigned long address, static int adjust_pte(struct vm_area_struct *vma, unsigned long address) { + spinlock_t *ptl; pgd_t *pgd; pmd_t *pmd; pte_t *pte; @@ -80,11 +81,19 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address) if (pmd_none_or_clear_bad(pmd)) return 0; - pte = pte_offset_map(pmd, address); + /* + * This is called while another page table is mapped, so we + * must use the nested version. This also means we need to + * open-code the spin-locking. + */ + ptl = pte_lockptr(vma->vm_mm, pmd); + pte = pte_offset_map_nested(pmd, address); + spin_lock(ptl); ret = do_adjust_pte(vma, address, pte); - pte_unmap(pte); + spin_unlock(ptl); + pte_unmap_nested(pte); return ret; } |