11573Srgrimes/*- 21573Srgrimes * Copyright (c) 2014 Ian Lepore <ian@freebsd.org> 31573Srgrimes * All rights reserved. 41573Srgrimes * 51573Srgrimes * Redistribution and use in source and binary forms, with or without 61573Srgrimes * modification, are permitted provided that the following conditions 71573Srgrimes * are met: 81573Srgrimes * 1. Redistributions of source code must retain the above copyright 91573Srgrimes * notice, this list of conditions and the following disclaimer. 101573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111573Srgrimes * notice, this list of conditions and the following disclaimer in the 121573Srgrimes * documentation and/or other materials provided with the distribution. 131573Srgrimes * 141573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 151573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16249808Semaste * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 171573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 181573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 191573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 201573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 211573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 221573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 231573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 241573Srgrimes * SUCH DAMAGE. 251573Srgrimes */ 261573Srgrimes 271573Srgrimes#include <sys/cdefs.h> 281573Srgrimes__FBSDID("$FreeBSD: releng/10.3/lib/libc/arm/aeabi/aeabi_unwind_exidx.c 269792 2014-08-10 22:26:29Z ian $"); 291573Srgrimes 301573Srgrimes#include <sys/types.h> 311573Srgrimes#include <machine/elf.h> 321573Srgrimes#include <link.h> 331573Srgrimes#include <stddef.h> 341573Srgrimes 351573Srgrimes/* 3692986Sobrien * ARM EABI unwind helper. 3792986Sobrien * 381573Srgrimes * This finds the exidx section address and size associated with a given code 3971579Sdeischen * address. There are separate implementations for static and dynamic code. 401573Srgrimes * 4171579Sdeischen * GCC expects this function to exist as __gnu_Unwind_Find_exidx(), clang and 42101776Stjr * BSD tools expect it to be dl_unwind_find_exidx(). Both have the same API, so 4335129Sjb * we set up an alias for GCC. 441573Srgrimes */ 4513545Sjulian__strong_reference(dl_unwind_find_exidx, __gnu_Unwind_Find_exidx); 46249810Semaste 471573Srgrimes/* 4813545Sjulian * Each entry in the exidx section is a pair of 32-bit words. We don't 4935129Sjb * interpret the contents of the entries here; this typedef is just a local 50127198Stjr * convenience for using sizeof() and doing pointer math. 51127198Stjr */ 52126806Stjrtypedef struct exidx_entry { 5335129Sjb uint32_t data[2]; 5413545Sjulian} exidx_entry; 551573Srgrimes 56#ifdef __PIC__ 57 58/* 59 * Unwind helper for dynamically linked code. 60 * 61 * This finds the shared object that contains the given address, and returns the 62 * address of the exidx section in that shared object along with the number of 63 * entries in that section, or NULL if it wasn't found. 64 */ 65void * 66dl_unwind_find_exidx(const void *pc, int *pcount) 67{ 68 const Elf_Phdr *hdr; 69 struct dl_phdr_info info; 70 int i; 71 72 if (_rtld_addr_phdr(pc, &info)) { 73 hdr = info.dlpi_phdr; 74 for (i = 0; i < info.dlpi_phnum; i++, hdr++) { 75 if (hdr->p_type == PT_ARM_EXIDX) { 76 *pcount = hdr->p_memsz / sizeof(exidx_entry); 77 return ((void *)(info.dlpi_addr + hdr->p_vaddr)); 78 } 79 } 80 } 81 return (NULL); 82} 83 84#else /* !__PIC__ */ 85 86/* 87 * Unwind helper for statically linked code. 88 * 89 * In a statically linked program, the linker populates a pair of symbols with 90 * the addresses of the start and end of the exidx table, so returning the 91 * address and count of elements is pretty straighforward. 92 */ 93void * 94dl_unwind_find_exidx(const void *pc, int *pcount) 95{ 96 extern struct exidx_entry __exidx_start; 97 extern struct exidx_entry __exidx_end; 98 99 *pcount = (int)(&__exidx_end - &__exidx_start); 100 return (&__exidx_start); 101} 102 103#endif /* __PIC__ */ 104 105