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authorVineet Gupta <vgupta@synopsys.com>2013-01-18 13:42:16 +0400
committerVineet Gupta <vgupta@synopsys.com>2013-02-11 18:30:30 +0400
commit14e968bad788de922a755a84b92cb29f8c1342e4 (patch)
tree5d1a38b177e2b63466ce00ee0165d04f04a2bceb /arch/arc/include/asm/smp.h
parentac4c244d4e5d914f9a5642cdcc03b18780e55dbc (diff)
downloadlinux-14e968bad788de922a755a84b92cb29f8c1342e4.tar.xz
ARC: Atomic/bitops/cmpxchg/barriers
This covers the UP / SMP (with no hardware assist for atomic r-m-w) as well as ARC700 LLOCK/SCOND insns based. Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc/include/asm/smp.h')
-rw-r--r--arch/arc/include/asm/smp.h34
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/arc/include/asm/smp.h b/arch/arc/include/asm/smp.h
new file mode 100644
index 000000000000..4341f3ba7d92
--- /dev/null
+++ b/arch/arc/include/asm/smp.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ASM_ARC_SMP_H
+#define __ASM_ARC_SMP_H
+
+/*
+ * ARC700 doesn't support atomic Read-Modify-Write ops.
+ * Originally Interrupts had to be disabled around code to gaurantee atomicity.
+ * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops
+ * based on retry-if-irq-in-atomic (with hardware assist).
+ * However despite these, we provide the IRQ disabling variant
+ *
+ * (1) These insn were introduced only in 4.10 release. So for older released
+ * support needed.
+ */
+#ifndef CONFIG_ARC_HAS_LLSC
+
+#include <linux/irqflags.h>
+
+#define atomic_ops_lock(flags) local_irq_save(flags)
+#define atomic_ops_unlock(flags) local_irq_restore(flags)
+
+#define bitops_lock(flags) local_irq_save(flags)
+#define bitops_unlock(flags) local_irq_restore(flags)
+
+#endif /* !CONFIG_ARC_HAS_LLSC */
+
+#endif