diff options
| -rw-r--r-- | arch/arm/include/asm/pgtable-2level.h | 7 | ||||
| -rw-r--r-- | arch/arm/include/asm/pgtable-3level.h | 3 | ||||
| -rw-r--r-- | arch/arm/lib/uaccess_with_memcpy.c | 41 |
3 files changed, 48 insertions, 3 deletions
diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h index f97ee02386ee..86a659a19526 100644 --- a/arch/arm/include/asm/pgtable-2level.h +++ b/arch/arm/include/asm/pgtable-2level.h @@ -181,6 +181,13 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr) #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,pte,ext) +/* + * We don't have huge page support for short descriptors, for the moment + * define empty stubs for use by pin_page_for_write. + */ +#define pmd_hugewillfault(pmd) (0) +#define pmd_thp_or_huge(pmd) (0) + #endif /* __ASSEMBLY__ */ #endif /* _ASM_PGTABLE_2LEVEL_H */ diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index 5689c18c85f5..39c54cfa03e9 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -206,6 +206,9 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr) #define __HAVE_ARCH_PMD_WRITE #define pmd_write(pmd) (!(pmd_val(pmd) & PMD_SECT_RDONLY)) +#define pmd_hugewillfault(pmd) (!pmd_young(pmd) || !pmd_write(pmd)) +#define pmd_thp_or_huge(pmd) (pmd_huge(pmd) || pmd_trans_huge(pmd)) + #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define pmd_trans_huge(pmd) (pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT)) #define pmd_trans_splitting(pmd) (pmd_val(pmd) & PMD_SECT_SPLITTING) diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c index 025f742dd4df..3e58d710013c 100644 --- a/arch/arm/lib/uaccess_with_memcpy.c +++ b/arch/arm/lib/uaccess_with_memcpy.c @@ -18,6 +18,7 @@ #include <linux/hardirq.h> /* for in_atomic() */ #include <linux/gfp.h> #include <linux/highmem.h> +#include <linux/hugetlb.h> #include <asm/current.h> #include <asm/page.h> @@ -40,7 +41,35 @@ pin_page_for_write(const void __user *_addr, pte_t **ptep, spinlock_t **ptlp) return 0; pmd = pmd_offset(pud, addr); - if (unlikely(pmd_none(*pmd) || pmd_bad(*pmd))) + if (unlikely(pmd_none(*pmd))) + return 0; + + /* + * A pmd can be bad if it refers to a HugeTLB or THP page. + * + * Both THP and HugeTLB pages have the same pmd layout + * and should not be manipulated by the pte functions. + * + * Lock the page table for the destination and check + * to see that it's still huge and whether or not we will + * need to fault on write, or if we have a splitting THP. + */ + if (unlikely(pmd_thp_or_huge(*pmd))) { + ptl = ¤t->mm->page_table_lock; + spin_lock(ptl); + if (unlikely(!pmd_thp_or_huge(*pmd) + || pmd_hugewillfault(*pmd) + || pmd_trans_splitting(*pmd))) { + spin_unlock(ptl); + return 0; + } + + *ptep = NULL; + *ptlp = ptl; + return 1; + } + + if (unlikely(pmd_bad(*pmd))) return 0; pte = pte_offset_map_lock(current->mm, pmd, addr, &ptl); @@ -94,7 +123,10 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n) from += tocopy; n -= tocopy; - pte_unmap_unlock(pte, ptl); + if (pte) + pte_unmap_unlock(pte, ptl); + else + spin_unlock(ptl); } if (!atomic) up_read(¤t->mm->mmap_sem); @@ -147,7 +179,10 @@ __clear_user_memset(void __user *addr, unsigned long n) addr += tocopy; n -= tocopy; - pte_unmap_unlock(pte, ptl); + if (pte) + pte_unmap_unlock(pte, ptl); + else + spin_unlock(ptl); } up_read(¤t->mm->mmap_sem); |