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Subject[PATCH 07/19] csky: Atomic operations
Date
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
---
arch/csky/kernel/atomic.S | 55 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
create mode 100644 arch/csky/kernel/atomic.S

diff --git a/arch/csky/kernel/atomic.S b/arch/csky/kernel/atomic.S
new file mode 100644
index 0000000..e6e9fd2
--- /dev/null
+++ b/arch/csky/kernel/atomic.S
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+#include <linux/linkage.h>
+#include <abi/entry.h>
+
+.text
+
+/*
+ * int csky_cmpxchg(int oldval, int newval, int *ptr)
+ *
+ * If *ptr != oldval && return 1,
+ * else *ptr = newval return 0.
+ */
+ENTRY(csky_cmpxchg)
+ USPTOKSP
+ mfcr a3, epc
+ INCTRAP a3
+
+ subi sp, 8
+ stw a3, (sp, 0)
+ mfcr a3, epsr
+ stw a3, (sp, 4)
+
+ psrset ee
+1:
+ ldw a3, (a2)
+ cmpne a0, a3
+ bt16 3f
+2:
+ stw a1, (a2)
+3:
+ mvc a0
+ ldw a3, (sp, 0)
+ mtcr a3, epc
+ ldw a3, (sp, 4)
+ mtcr a3, epsr
+ addi sp, 8
+ KSPTOUSP
+ rte
+END(csky_cmpxchg)
+
+/*
+ * Called from tlbmodified exception
+ */
+ENTRY(csky_cmpxchg_fixup)
+ mfcr a0, epc
+ lrw a1, 2b
+ cmpne a1, a0
+ bt 1f
+ subi a1, (2b - 1b)
+ stw a1, (sp, 0)
+1:
+ rts
+END(csky_cmpxchg_fixup)
+
--
2.7.4
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