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-rw-r--r--arch/arc/include/asm/arcregs.h2
-rw-r--r--arch/arc/kernel/process.c20
2 files changed, 13 insertions, 9 deletions
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 7f3f9f63708c..1bd24ec3e350 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -43,12 +43,14 @@
#define STATUS_AE_BIT 5 /* Exception active */
#define STATUS_DE_BIT 6 /* PC is in delay slot */
#define STATUS_U_BIT 7 /* User/Kernel mode */
+#define STATUS_Z_BIT 11
#define STATUS_L_BIT 12 /* Loop inhibit */
/* These masks correspond to the status word(STATUS_32) bits */
#define STATUS_AE_MASK (1<<STATUS_AE_BIT)
#define STATUS_DE_MASK (1<<STATUS_DE_BIT)
#define STATUS_U_MASK (1<<STATUS_U_BIT)
+#define STATUS_Z_MASK (1<<STATUS_Z_BIT)
#define STATUS_L_MASK (1<<STATUS_L_BIT)
/*
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)