Merge tag 'arc-4.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC fixes from Vineet Gupta:

 - mmap handler for dma ops as generic handler no longer works for us
   [Alexey]

 - Fixes for EZChip platform [Noam]

 - Fix RTC clocksource driver build issue

 - ARC IRQ handling fixes [Yuriy]

 - Revert a recent makefile change which doesn't go well with oldish
   tools out in the wild

* tag 'arc-4.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARCv2: MCIP: Use IDU_M_DISTRI_DEST mode if there is only 1 destination core
  ARC: IRQ: Do not use hwirq as virq and vice versa
  ARC: [plat-eznps] set default baud for early console
  ARC: [plat-eznps] remove IPI clear from SMP operations
  Revert "ARC: build: retire old toggles"
  ARC: timer: rtc: implement read loop in "C" vs. inline asm
  ARC: change return value of userspace cmpxchg assist syscall
  arc: Implement arch-specific dma_map_ops.mmap
  ARC: [SMP] avoid overriding present cpumask
  ARC: Enable PERF_EVENTS in nSIM driven platforms

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)