diff options
Diffstat (limited to 'lib/libc/arm/aeabi/aeabi_unwind_exidx.c')
| -rw-r--r-- | lib/libc/arm/aeabi/aeabi_unwind_exidx.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/lib/libc/arm/aeabi/aeabi_unwind_exidx.c b/lib/libc/arm/aeabi/aeabi_unwind_exidx.c new file mode 100644 index 000000000000..cf61922d4304 --- /dev/null +++ b/lib/libc/arm/aeabi/aeabi_unwind_exidx.c @@ -0,0 +1,101 @@ +/*- + * Copyright (c) 2014 Ian Lepore <ian@freebsd.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/types.h> +#include <machine/elf.h> +#include <link.h> +#include <stddef.h> + +/* + * ARM EABI unwind helper. + * + * This finds the exidx section address and size associated with a given code + * address. There are separate implementations for static and dynamic code. + * + * GCC expects this function to exist as __gnu_Unwind_Find_exidx(), clang and + * BSD tools expect it to be dl_unwind_find_exidx(). Both have the same API, so + * we set up an alias for GCC. + */ +__strong_reference(dl_unwind_find_exidx, __gnu_Unwind_Find_exidx); + +/* + * Each entry in the exidx section is a pair of 32-bit words. We don't + * interpret the contents of the entries here; this typedef is just a local + * convenience for using sizeof() and doing pointer math. + */ +typedef struct exidx_entry { + uint32_t data[2]; +} exidx_entry; + +#ifdef __PIC__ + +/* + * Unwind helper for dynamically linked code. + * + * This finds the shared object that contains the given address, and returns the + * address of the exidx section in that shared object along with the number of + * entries in that section, or NULL if it wasn't found. + */ +void * +dl_unwind_find_exidx(const void *pc, int *pcount) +{ + const Elf_Phdr *hdr; + struct dl_phdr_info info; + int i; + + if (_rtld_addr_phdr(pc, &info)) { + hdr = info.dlpi_phdr; + for (i = 0; i < info.dlpi_phnum; i++, hdr++) { + if (hdr->p_type == PT_ARM_EXIDX) { + *pcount = hdr->p_memsz / sizeof(exidx_entry); + return ((void *)(info.dlpi_addr + hdr->p_vaddr)); + } + } + } + return (NULL); +} + +#else /* !__PIC__ */ + +/* + * Unwind helper for statically linked code. + * + * In a statically linked program, the linker populates a pair of symbols with + * the addresses of the start and end of the exidx table, so returning the + * address and count of elements is pretty straighforward. + */ +void * +dl_unwind_find_exidx(const void *pc, int *pcount) +{ + extern struct exidx_entry __exidx_start; + extern struct exidx_entry __exidx_end; + + *pcount = (int)(&__exidx_end - &__exidx_start); + return (&__exidx_start); +} + +#endif /* __PIC__ */ + |