65 lines
2.5 KiB
C
65 lines
2.5 KiB
C
/* $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:39 joerg Exp $ */
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/*-
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* Copyright (c) 2018 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _SPARC_ELF_SUPPORT_H
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#define _SPARC_ELF_SUPPORT_H
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static inline void
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sparc_write_branch(void *where_, void *target)
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{
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const unsigned int BAA = 0x30800000U; /* ba,a (offset / 4) */
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const unsigned int SETHI = 0x03000000U; /* sethi %hi(0), %g1 */
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const unsigned int JMP = 0x81c06000U; /* jmpl %g1+%lo(0), %g0 */
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unsigned int *where = (unsigned int *)where_;
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unsigned long value = (unsigned long)target;
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unsigned long offset = value - (unsigned long)where;
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#define HIVAL(v, s) (((v) >> (s)) & 0x003fffffU)
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#define LOVAL(v, s) (((v) >> (s)) & 0x000003ffU)
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if (offset + 0x800000 <= 0x7ffffc) {
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/* Displacement is within 8MB, use a direct branch. */
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where[0] = BAA | ((offset >> 2) & 0x3fffff);
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__asm volatile("iflush %0+0" : : "r" (where));
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return;
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}
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/*
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* The absolute address is a 32bit value.
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* This can be encoded as:
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* sethi %hi(value), %g1
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* jmp %g1+%lo(value)
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*/
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where[1] = JMP | LOVAL(value, 0);
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__asm volatile("iflush %0+4" : : "r" (where));
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where[0] = SETHI | HIVAL(value, 10);
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__asm volatile("iflush %0+0" : : "r" (where));
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#undef HIVAL
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#undef LOVAL
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}
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#endif
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