148 lines
3.2 KiB
C
148 lines
3.2 KiB
C
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/*
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* Atomic futex routines
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*
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* Based on the PowerPC implementataion
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Copyright (C) 2013 TangoTec Ltd.
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*
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* Baruch Siach <baruch@tkos.co.il>
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*/
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#ifndef _ASM_XTENSA_FUTEX_H
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#define _ASM_XTENSA_FUTEX_H
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#ifdef __KERNEL__
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#include <linux/futex.h>
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#include <linux/uaccess.h>
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#include <linux/errno.h>
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#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
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__asm__ __volatile( \
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"1: l32i %0, %2, 0\n" \
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insn "\n" \
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" wsr %0, scompare1\n" \
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"2: s32c1i %1, %2, 0\n" \
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" bne %1, %0, 1b\n" \
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" movi %1, 0\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .align 4\n" \
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"4: .long 3b\n" \
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"5: l32r %0, 4b\n" \
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" movi %1, %3\n" \
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" jx %0\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .long 1b,5b,2b,5b\n" \
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" .previous\n" \
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: "=&r" (oldval), "=&r" (ret) \
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: "r" (uaddr), "I" (-EFAULT), "r" (oparg) \
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: "memory")
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static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
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{
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int op = (encoded_op >> 28) & 7;
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int cmp = (encoded_op >> 24) & 15;
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int oparg = (encoded_op << 8) >> 20;
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int cmparg = (encoded_op << 20) >> 20;
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int oldval = 0, ret;
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if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
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oparg = 1 << oparg;
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if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
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return -EFAULT;
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#if !XCHAL_HAVE_S32C1I
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return -ENOSYS;
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#endif
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pagefault_disable();
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switch (op) {
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case FUTEX_OP_SET:
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__futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ADD:
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__futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
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oparg);
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break;
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case FUTEX_OP_OR:
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__futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
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oparg);
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break;
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case FUTEX_OP_ANDN:
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__futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
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~oparg);
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break;
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case FUTEX_OP_XOR:
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__futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
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oparg);
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break;
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default:
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ret = -ENOSYS;
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}
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pagefault_enable();
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if (ret)
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return ret;
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switch (cmp) {
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case FUTEX_OP_CMP_EQ: return (oldval == cmparg);
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case FUTEX_OP_CMP_NE: return (oldval != cmparg);
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case FUTEX_OP_CMP_LT: return (oldval < cmparg);
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case FUTEX_OP_CMP_GE: return (oldval >= cmparg);
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case FUTEX_OP_CMP_LE: return (oldval <= cmparg);
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case FUTEX_OP_CMP_GT: return (oldval > cmparg);
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}
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return -ENOSYS;
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}
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static inline int
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futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
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u32 oldval, u32 newval)
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{
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int ret = 0;
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u32 prev;
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if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
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return -EFAULT;
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#if !XCHAL_HAVE_S32C1I
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return -ENOSYS;
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#endif
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__asm__ __volatile__ (
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" # futex_atomic_cmpxchg_inatomic\n"
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"1: l32i %1, %3, 0\n"
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" mov %0, %5\n"
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" wsr %1, scompare1\n"
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"2: s32c1i %0, %3, 0\n"
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"3:\n"
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" .section .fixup,\"ax\"\n"
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" .align 4\n"
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"4: .long 3b\n"
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"5: l32r %1, 4b\n"
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" movi %0, %6\n"
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" jx %1\n"
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" .previous\n"
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" .section __ex_table,\"a\"\n"
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" .long 1b,5b,2b,5b\n"
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" .previous\n"
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: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
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: "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT)
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: "memory");
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*uval = prev;
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return ret;
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}
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#endif /* __KERNEL__ */
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#endif /* _ASM_XTENSA_FUTEX_H */
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