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| /*
| * Atomic futex routines
| *
| * Based on the PowerPC implementataion
| *
| * 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.
| *
| * Copyright (C) 2013 TangoTec Ltd.
| *
| * Baruch Siach <baruch@tkos.co.il>
| */
|
| #ifndef _ASM_XTENSA_FUTEX_H
| #define _ASM_XTENSA_FUTEX_H
|
| #ifdef __KERNEL__
|
| #include <linux/futex.h>
| #include <linux/uaccess.h>
| #include <linux/errno.h>
|
| #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
| __asm__ __volatile( \
| "1: l32i %0, %2, 0\n" \
| insn "\n" \
| " wsr %0, scompare1\n" \
| "2: s32c1i %1, %2, 0\n" \
| " bne %1, %0, 1b\n" \
| " movi %1, 0\n" \
| "3:\n" \
| " .section .fixup,\"ax\"\n" \
| " .align 4\n" \
| "4: .long 3b\n" \
| "5: l32r %0, 4b\n" \
| " movi %1, %3\n" \
| " jx %0\n" \
| " .previous\n" \
| " .section __ex_table,\"a\"\n" \
| " .long 1b,5b,2b,5b\n" \
| " .previous\n" \
| : "=&r" (oldval), "=&r" (ret) \
| : "r" (uaddr), "I" (-EFAULT), "r" (oparg) \
| : "memory")
|
| static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
| u32 __user *uaddr)
| {
| int oldval = 0, ret;
|
| #if !XCHAL_HAVE_S32C1I
| return -ENOSYS;
| #endif
|
| pagefault_disable();
|
| switch (op) {
| case FUTEX_OP_SET:
| __futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
| break;
| case FUTEX_OP_ADD:
| __futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
| oparg);
| break;
| case FUTEX_OP_OR:
| __futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
| oparg);
| break;
| case FUTEX_OP_ANDN:
| __futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
| ~oparg);
| break;
| case FUTEX_OP_XOR:
| __futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
| oparg);
| break;
| default:
| ret = -ENOSYS;
| }
|
| pagefault_enable();
|
| if (!ret)
| *oval = oldval;
|
| return ret;
| }
|
| static inline int
| futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
| u32 oldval, u32 newval)
| {
| int ret = 0;
|
| if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
| return -EFAULT;
|
| #if !XCHAL_HAVE_S32C1I
| return -ENOSYS;
| #endif
|
| __asm__ __volatile__ (
| " # futex_atomic_cmpxchg_inatomic\n"
| " wsr %5, scompare1\n"
| "1: s32c1i %1, %4, 0\n"
| " s32i %1, %6, 0\n"
| "2:\n"
| " .section .fixup,\"ax\"\n"
| " .align 4\n"
| "3: .long 2b\n"
| "4: l32r %1, 3b\n"
| " movi %0, %7\n"
| " jx %1\n"
| " .previous\n"
| " .section __ex_table,\"a\"\n"
| " .long 1b,4b\n"
| " .previous\n"
| : "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval)
| : "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT)
| : "memory");
|
| return ret;
| }
|
| #endif /* __KERNEL__ */
| #endif /* _ASM_XTENSA_FUTEX_H */
|
|
