diff options
Diffstat (limited to 'arch/arc/kernel')
| -rw-r--r-- | arch/arc/kernel/process.c | 47 |
1 files changed, 36 insertions, 11 deletions
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index 5ac3b547453f..4674541eba3f 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -47,7 +47,8 @@ SYSCALL_DEFINE0(arc_gettls) SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) { struct pt_regs *regs = current_pt_regs(); - int uval = -EFAULT; + u32 uval; + int ret; /* * This is only for old cores lacking LLOCK/SCOND, which by defintion @@ -60,23 +61,47 @@ SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) /* Z indicates to userspace if operation succeded */ regs->status32 &= ~STATUS_Z_MASK; - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) - return -EFAULT; + ret = access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr)); + if (!ret) + goto fail; +again: preempt_disable(); - if (__get_user(uval, uaddr)) - goto done; + ret = __get_user(uval, uaddr); + if (ret) + goto fault; - if (uval == expected) { - if (!__put_user(new, uaddr)) - regs->status32 |= STATUS_Z_MASK; - } + if (uval != expected) + goto out; -done: - preempt_enable(); + ret = __put_user(new, uaddr); + if (ret) + goto fault; + + regs->status32 |= STATUS_Z_MASK; +out: + preempt_enable(); return uval; + +fault: + preempt_enable(); + + if (unlikely(ret != -EFAULT)) + goto fail; + + down_read(¤t->mm->mmap_sem); + ret = fixup_user_fault(current, current->mm, (unsigned long) uaddr, + FAULT_FLAG_WRITE, NULL); + up_read(¤t->mm->mmap_sem); + + if (likely(!ret)) + goto again; + +fail: + force_sig(SIGSEGV, current); + return ret; } #ifdef CONFIG_ISA_ARCV2 |