x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 140 insertions, 0 deletions

diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
new file mode 100644
index 000000000000..06b924ef6fa5
--- /dev/null
+++ b/arch/x86/include/asm/futex.h
@@ -0,0 +1,140 @@
+#ifndef ASM_X86__FUTEX_H
+#define ASM_X86__FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+
+#include <asm/asm.h>
+#include <asm/errno.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+
+#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg)     \
+        asm volatile("1:\t" insn "\n"                           \
+                     "2:\t.section .fixup,\"ax\"\n"             \
+                     "3:\tmov\t%3, %1\n"                        \
+                     "\tjmp\t2b\n"                              \
+                     "\t.previous\n"                            \
+                     _ASM_EXTABLE(1b, 3b)                       \
+                     : "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
+                     : "i" (-EFAULT), "0" (oparg), "1" (0))
+
+#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg)     \
+        asm volatile("1:\tmovl  %2, %0\n"                       \
+                     "\tmovl\t%0, %3\n"                         \
+                     "\t" insn "\n"                             \
+                     "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n"     \
+                     "\tjnz\t1b\n"                              \
+                     "3:\t.section .fixup,\"ax\"\n"             \
+                     "4:\tmov\t%5, %1\n"                        \
+                     "\tjmp\t3b\n"                              \
+                     "\t.previous\n"                            \
+                     _ASM_EXTABLE(1b, 4b)                       \
+                     _ASM_EXTABLE(2b, 4b)                       \
+                     : "=&a" (oldval), "=&r" (ret),             \
+                       "+m" (*uaddr), "=&r" (tem)               \
+                     : "r" (oparg), "i" (-EFAULT), "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;
+
+#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
+        /* Real i386 machines can only support FUTEX_OP_SET */
+        if (op != FUTEX_OP_SET && boot_cpu_data.x86 == 3)
+                return -ENOSYS;
+#endif
+
+        pagefault_disable();
+
+        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;
+        }
+
+        pagefault_enable();
+
+        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;
+}
+
+static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
+                                                int newval)
+{
+
+#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_BSWAP)
+        /* Real i386 machines have no cmpxchg instruction */
+        if (boot_cpu_data.x86 == 3)
+                return -ENOSYS;
+#endif
+
+        if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+                return -EFAULT;
+
+        asm volatile("1:\t" LOCK_PREFIX "cmpxchgl %3, %1\n"
+                     "2:\t.section .fixup, \"ax\"\n"
+                     "3:\tmov     %2, %0\n"
+                     "\tjmp     2b\n"
+                     "\t.previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : "=a" (oldval), "+m" (*uaddr)
+                     : "i" (-EFAULT), "r" (newval), "0" (oldval)
+                     : "memory"
+        );
+
+        return oldval;
+}
+
+#endif
+#endif /* ASM_X86__FUTEX_H */