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Diffstat (limited to 'include/asm-x86_64/futex.h')
-rw-r--r--include/asm-x86_64/futex.h98
1 files changed, 98 insertions, 0 deletions
diff --git a/include/asm-x86_64/futex.h b/include/asm-x86_64/futex.h
new file mode 100644
index 000000000000..8602c09bf89e
--- /dev/null
+++ b/include/asm-x86_64/futex.h
@@ -0,0 +1,98 @@
+#ifndef _ASM_FUTEX_H
+#define _ASM_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <asm/errno.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
+ __asm__ __volatile ( \
+"1: " insn "\n" \
+"2: .section .fixup,\"ax\"\n\
+3: mov %3, %1\n\
+ jmp 2b\n\
+ .previous\n\
+ .section __ex_table,\"a\"\n\
+ .align 8\n\
+ .quad 1b,3b\n\
+ .previous" \
+ : "=r" (oldval), "=r" (ret), "=m" (*uaddr) \
+ : "i" (-EFAULT), "m" (*uaddr), "0" (oparg), "1" (0))
+
+#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
+ __asm__ __volatile ( \
+"1: movl %2, %0\n\
+ movl %0, %3\n" \
+ insn "\n" \
+"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\
+ jnz 1b\n\
+3: .section .fixup,\"ax\"\n\
+4: mov %5, %1\n\
+ jmp 3b\n\
+ .previous\n\
+ .section __ex_table,\"a\"\n\
+ .align 8\n\
+ .quad 1b,4b,2b,4b\n\
+ .previous" \
+ : "=&a" (oldval), "=&r" (ret), "=m" (*uaddr), \
+ "=&r" (tem) \
+ : "r" (oparg), "i" (-EFAULT), "m" (*uaddr), "1" (0))
+
+static inline int
+futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
+{
+ int op = (encoded_op >> 28) & 7;
+ int cmp = (encoded_op >> 24) & 15;
+ int oparg = (encoded_op << 8) >> 20;
+ int cmparg = (encoded_op << 20) >> 20;
+ int oldval = 0, ret, tem;
+ if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+ oparg = 1 << oparg;
+
+ if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
+ return -EFAULT;
+
+ inc_preempt_count();
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ADD:
+ __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
+ uaddr, oparg);
+ break;
+ case FUTEX_OP_OR:
+ __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ANDN:
+ __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
+ break;
+ case FUTEX_OP_XOR:
+ __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ dec_preempt_count();
+
+ if (!ret) {
+ switch (cmp) {
+ case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
+ case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
+ case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
+ case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
+ case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
+ case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
+ default: ret = -ENOSYS;
+ }
+ }
+ return ret;
+}
+
+#endif
+#endif