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| author | Jonathan Corbet <corbet@lwn.net> | 2016-12-27 12:53:44 -0700 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2016-12-27 12:53:44 -0700 |
| commit | 54ab6db0909061ab7ee07233d3cab86d29f86e6c (patch) | |
| tree | a7650ab5c0fa3a6a3841de8e8693041b3e009054 /arch/arc/kernel/process.c | |
| parent | 217e2bfab22e740227df09f22165e834cddd8a3b (diff) | |
| parent | 7ce7d89f48834cefece7804d38fc5d85382edf77 (diff) | |
Merge tag 'v4.10-rc1' into docs-next
Linux 4.10-rc1
Diffstat (limited to 'arch/arc/kernel/process.c')
| -rw-r--r-- | arch/arc/kernel/process.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index 59aa43cb146e..a41a79a4f4fe 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -43,8 +43,8 @@ SYSCALL_DEFINE0(arc_gettls) SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) { - int uval; - int ret; + struct pt_regs *regs = current_pt_regs(); + int uval = -EFAULT; /* * This is only for old cores lacking LLOCK/SCOND, which by defintion @@ -54,24 +54,26 @@ SYSCALL_DEFINE3(arc_usr_cmpxchg, int *, uaddr, int, expected, int, new) */ WARN_ON_ONCE(IS_ENABLED(CONFIG_SMP)); + /* Z indicates to userspace if operation succeded */ + regs->status32 &= ~STATUS_Z_MASK; + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; preempt_disable(); - ret = __get_user(uval, uaddr); - if (ret) + if (__get_user(uval, uaddr)) goto done; - if (uval != expected) - ret = -EAGAIN; - else - ret = __put_user(new, uaddr); + if (uval == expected) { + if (!__put_user(new, uaddr)) + regs->status32 |= STATUS_Z_MASK; + } done: preempt_enable(); - return ret; + return uval; } void arch_cpu_idle(void) |