1 /* $NetBSD: elf_support.h,v 1.1 2018/03/29 13:23:39 joerg Exp $ */ 2 3 /*- 4 * Copyright (c) 2018 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 #ifndef _SPARC_ELF_SUPPORT_H 29 #define _SPARC_ELF_SUPPORT_H 30 31 static inline void 32 sparc_write_branch(void *where_, void *target) 33 { 34 const unsigned int BAA = 0x30800000U; /* ba,a (offset / 4) */ 35 const unsigned int SETHI = 0x03000000U; /* sethi %hi(0), %g1 */ 36 const unsigned int JMP = 0x81c06000U; /* jmpl %g1+%lo(0), %g0 */ 37 38 unsigned int *where = (unsigned int *)where_; 39 unsigned long value = (unsigned long)target; 40 unsigned long offset = value - (unsigned long)where; 41 42 #define HIVAL(v, s) (((v) >> (s)) & 0x003fffffU) 43 #define LOVAL(v, s) (((v) >> (s)) & 0x000003ffU) 44 if (offset + 0x800000 <= 0x7ffffc) { 45 /* Displacement is within 8MB, use a direct branch. */ 46 where[0] = BAA | ((offset >> 2) & 0x3fffff); 47 __asm volatile("iflush %0+0" : : "r" (where)); 48 return; 49 } 50 51 /* 52 * The absolute address is a 32bit value. 53 * This can be encoded as: 54 * sethi %hi(value), %g1 55 * jmp %g1+%lo(value) 56 */ 57 where[1] = JMP | LOVAL(value, 0); 58 __asm volatile("iflush %0+4" : : "r" (where)); 59 where[0] = SETHI | HIVAL(value, 10); 60 __asm volatile("iflush %0+0" : : "r" (where)); 61 #undef HIVAL 62 #undef LOVAL 63 } 64 #endif 65