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Subject[PATCH v6 14/36] nds32: Atomic operations
Date
From: Greentime Hu <greentime@andestech.com>

This patch includes the atomic and futex operations. Many atomic operations use
the load-lock word(llw) and store-condition word(scw) operations.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
---
arch/nds32/include/asm/barrier.h | 15 ++++++
arch/nds32/include/asm/futex.h | 103 ++++++++++++++++++++++++++++++++++++++
2 files changed, 118 insertions(+)
create mode 100644 arch/nds32/include/asm/barrier.h
create mode 100644 arch/nds32/include/asm/futex.h

diff --git a/arch/nds32/include/asm/barrier.h b/arch/nds32/include/asm/barrier.h
new file mode 100644
index 0000000..faafc37
--- /dev/null
+++ b/arch/nds32/include/asm/barrier.h
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __NDS32_ASM_BARRIER_H
+#define __NDS32_ASM_BARRIER_H
+
+#ifndef __ASSEMBLY__
+#define mb() asm volatile("msync all":::"memory")
+#define rmb() asm volatile("msync all":::"memory")
+#define wmb() asm volatile("msync store":::"memory")
+#include <asm-generic/barrier.h>
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __NDS32_ASM_BARRIER_H */
diff --git a/arch/nds32/include/asm/futex.h b/arch/nds32/include/asm/futex.h
new file mode 100644
index 0000000..eab5e84
--- /dev/null
+++ b/arch/nds32/include/asm/futex.h
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#ifndef __NDS32_FUTEX_H__
+#define __NDS32_FUTEX_H__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+
+#define __futex_atomic_ex_table(err_reg) \
+ " .pushsection __ex_table,\"a\"\n" \
+ " .align 3\n" \
+ " .long 1b, 4f\n" \
+ " .long 2b, 4f\n" \
+ " .popsection\n" \
+ " .pushsection .fixup,\"ax\"\n" \
+ "4: move %0, " err_reg "\n" \
+ " j 3b\n" \
+ " .popsection"
+
+#define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
+ smp_mb(); \
+ asm volatile( \
+ " movi $ta, #0\n" \
+ "1: llw %1, [%2+$ta]\n" \
+ " " insn "\n" \
+ "2: scw %0, [%2+$ta]\n" \
+ " beqz %0, 1b\n" \
+ " movi %0, #0\n" \
+ "3:\n" \
+ __futex_atomic_ex_table("%4") \
+ : "=&r" (ret), "=&r" (oldval) \
+ : "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
+ : "cc", "memory")
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 * uval, u32 __user * uaddr,
+ u32 oldval, u32 newval)
+{
+ int ret = 0;
+ u32 val, tmp, flags;
+
+ if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+ return -EFAULT;
+
+ smp_mb();
+ asm volatile (" movi $ta, #0\n"
+ "1: llw %1, [%6 + $ta]\n"
+ " sub %3, %1, %4\n"
+ " cmovz %2, %5, %3\n"
+ " cmovn %2, %1, %3\n"
+ "2: scw %2, [%6 + $ta]\n"
+ " beqz %2, 1b\n"
+ "3:\n " __futex_atomic_ex_table("%7")
+ :"+&r"(ret), "=&r"(val), "=&r"(tmp), "=&r"(flags)
+ :"r"(oldval), "r"(newval), "r"(uaddr), "i"(-EFAULT)
+ :"$ta", "memory");
+ smp_mb();
+
+ *uval = val;
+ return ret;
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+ int oldval = 0, ret;
+
+
+ pagefault_disable();
+ switch (op) {
+ case FUTEX_OP_SET:
+ __futex_atomic_op("move %0, %3", ret, oldval, tmp, uaddr,
+ oparg);
+ break;
+ case FUTEX_OP_ADD:
+ __futex_atomic_op("add %0, %1, %3", ret, oldval, tmp, uaddr,
+ oparg);
+ break;
+ case FUTEX_OP_OR:
+ __futex_atomic_op("or %0, %1, %3", ret, oldval, tmp, uaddr,
+ oparg);
+ break;
+ case FUTEX_OP_ANDN:
+ __futex_atomic_op("and %0, %1, %3", ret, oldval, tmp, uaddr,
+ ~oparg);
+ break;
+ case FUTEX_OP_XOR:
+ __futex_atomic_op("xor %0, %1, %3", ret, oldval, tmp, uaddr,
+ oparg);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ pagefault_enable();
+
+ if (!ret)
+ *oval = oldval;
+
+ return ret;
+}
+#endif /* __NDS32_FUTEX_H__ */
--
1.7.9.5
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