1 /* $NetBSD: h_r_rel.c,v 1.1 2025/05/02 03:26:26 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2025 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 29 #include <sys/cdefs.h> 30 __RCSID("$NetBSD: h_r_rel.c,v 1.1 2025/05/02 03:26:26 riastradh Exp $"); 31 32 #include <stdio.h> 33 34 /* 35 * When built as position-independent executable, the value of foop and 36 * foopp should be computed either via R_*_RELATIVE or R_*_REL32 or 37 * similar, which -- ports that support it -- may be compressed into a 38 * SHT_RELR section. 39 * 40 * One pointer indirection is enough to produce this effect, but we use 41 * two pointer indirections to increase the probability of a crash in 42 * case the relocations are done wrong. 43 */ 44 static int foo = 0x5f4d7635; 45 static int *volatile foop = &foo; 46 static int *volatile *volatile foopp = &foop; 47 48 /* 49 * The RELR section compresses relocations for adjacent addresses into 50 * bitmaps of 31 or 63 bits apiece. Create a bunch of consecutive 51 * addresses to relocate, punctuated by the occasional non-relocated 52 * address (null), to check for fencepost errors in the bitmap 53 * iteration. 54 */ 55 static int bar[] = { 56 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 57 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 58 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 59 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 60 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 61 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 62 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 63 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 64 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 65 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 66 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 67 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 68 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 69 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 70 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 71 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 72 }; 73 74 static int *volatile barp[] = { 75 &bar[0x00], &bar[0x01], &bar[0x02], &bar[0x03], 76 &bar[0x04], &bar[0x05], &bar[0x06], &bar[0x07], 77 &bar[0x08], &bar[0x09], &bar[0x0a], &bar[0x0b], 78 &bar[0x0c], &bar[0x0d], &bar[0x0e], &bar[0x0f], 79 &bar[0x10], &bar[0x11], &bar[0x12], &bar[0x13], 80 &bar[0x14], &bar[0x15], &bar[0x16], &bar[0x17], 81 &bar[0x18], &bar[0x19], &bar[0x1a], &bar[0x1b], 82 &bar[0x1c], &bar[0x1d], &bar[0x1e], &bar[0x1f], 83 &bar[0x20], &bar[0x21], &bar[0x22], &bar[0x23], 84 &bar[0x24], &bar[0x25], &bar[0x26], &bar[0x27], 85 &bar[0x28], &bar[0x29], &bar[0x2a], &bar[0x2b], 86 &bar[0x2c], &bar[0x2d], &bar[0x2e], &bar[0x2f], 87 &bar[0x30], &bar[0x31], &bar[0x32], &bar[0x33], 88 &bar[0x34], &bar[0x35], &bar[0x36], &bar[0x37], 89 &bar[0x38], &bar[0x39], &bar[0x3a], &bar[0x3b], 90 &bar[0x3c], &bar[0x3d], &bar[0x3e], &bar[0x3f], 91 NULL, &bar[0x41], &bar[0x42], &bar[0x43], /* test a clear bit */ 92 &bar[0x44], &bar[0x45], &bar[0x46], &bar[0x47], 93 &bar[0x48], &bar[0x49], &bar[0x4a], &bar[0x4b], 94 &bar[0x4c], &bar[0x4d], &bar[0x4e], &bar[0x4f], 95 &bar[0x50], &bar[0x51], &bar[0x52], &bar[0x53], 96 &bar[0x54], &bar[0x55], &bar[0x56], &bar[0x57], 97 &bar[0x58], &bar[0x59], &bar[0x5a], &bar[0x5b], 98 &bar[0x5c], &bar[0x5d], &bar[0x5e], &bar[0x5f], 99 &bar[0x60], &bar[0x61], &bar[0x62], &bar[0x63], 100 &bar[0x64], &bar[0x65], &bar[0x66], &bar[0x67], 101 &bar[0x68], &bar[0x69], &bar[0x6a], &bar[0x6b], 102 &bar[0x6c], &bar[0x6d], &bar[0x6e], &bar[0x6f], 103 &bar[0x70], &bar[0x71], &bar[0x72], &bar[0x73], 104 &bar[0x74], &bar[0x75], &bar[0x76], &bar[0x77], 105 &bar[0x78], &bar[0x79], &bar[0x7a], &bar[0x7b], 106 &bar[0x7c], &bar[0x7d], &bar[0x7e], &bar[0x7f], 107 NULL, /* confirm we stop at the end */ 108 }; 109 110 static int baz = -0x1adbd477; 111 static int *volatile bazp = &baz; 112 113 int 114 main(void) 115 { 116 int i, result = 0; 117 118 if (**foopp != 0x5f4d7635) { 119 fprintf(stderr, "foo @ %p, foop = %p, *foop = %p," 120 " **foopp = 0x%x\n", 121 &foo, foop, *foopp, **foopp); 122 result |= 1; 123 } 124 for (i = 0; i < (int)__arraycount(barp); i++) { 125 if (i == 0x40 || i == 0x80) { 126 if (barp[i] != NULL) { 127 fprintf(stderr, "barp[%u] = %p\n", 128 i, barp[i]); 129 } 130 } else { 131 if (*barp[i] != i) { 132 fprintf(stderr, "bar[%u] @ %p, barp[%u] = %p," 133 " *barp[%u] = %u\n", 134 i, &bar[i], i, barp[i], i, *barp[i]); 135 result |= 1; 136 } 137 } 138 } 139 if (*bazp != -0x1adbd477) { 140 fprintf(stderr, "baz @ %p, bazp = %p, *bazp = 0x%x\n", 141 &baz, bazp, *bazp); 142 result |= 1; 143 } 144 145 return result; 146 } 147
Indexes created Sat Sep 20 22:09:52 GMT 2025