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Diffstat (limited to 'arch/arm/kernel/traps.c')
-rw-r--r--arch/arm/kernel/traps.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index baa09601a64..66e5a0516f2 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -483,29 +483,33 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
unsigned long addr = regs->ARM_r2;
struct mm_struct *mm = current->mm;
pgd_t *pgd; pmd_t *pmd; pte_t *pte;
+ spinlock_t *ptl;
regs->ARM_cpsr &= ~PSR_C_BIT;
- spin_lock(&mm->page_table_lock);
+ down_read(&mm->mmap_sem);
pgd = pgd_offset(mm, addr);
if (!pgd_present(*pgd))
goto bad_access;
pmd = pmd_offset(pgd, addr);
if (!pmd_present(*pmd))
goto bad_access;
- pte = pte_offset_map(pmd, addr);
- if (!pte_present(*pte) || !pte_write(*pte))
+ pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ if (!pte_present(*pte) || !pte_write(*pte)) {
+ pte_unmap_unlock(pte, ptl);
goto bad_access;
+ }
val = *(unsigned long *)addr;
val -= regs->ARM_r0;
if (val == 0) {
*(unsigned long *)addr = regs->ARM_r1;
regs->ARM_cpsr |= PSR_C_BIT;
}
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(pte, ptl);
+ up_read(&mm->mmap_sem);
return val;
bad_access:
- spin_unlock(&mm->page_table_lock);
+ up_read(&mm->mmap_sem);
/* simulate a write access fault */
do_DataAbort(addr, 15 + (1 << 11), regs);
return -1;