From dc12567a53c88d7a91b9d71db3775782c7f35c84 Mon Sep 17 00:00:00 2001 From: Josh Kunz Date: Fri, 16 Aug 2019 16:34:22 -0700 Subject: [PATCH] linux-user: Support gdb 'qOffsets' query for ELF MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is needed to support debugging PIE ELF binaries running under QEMU user mode. Currently, `code_offset` and `data_offset` remain unset for all ELF binaries, so GDB is unable to correctly locate the position of the binary's text and data. The fields `code_offset`, and `data_offset` were originally added way back in 2006 to support debugging of bFMT executables (978efd6aac6), and support was just never added for ELF. Since non-PIE binaries are loaded at exactly the address specified in the binary, GDB does not need to relocate any symbols, so the buggy behavior is not normally observed. http://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html#index-qOffsets-packet Buglink: https://bugs.launchpad.net/qemu/+bug/1528239 Signed-off-by: Josh Kunz Reviewed-by: Laurent Vivier Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20190816233422.16715-1-jkz@google.com> [lv: added link to documentation] Signed-off-by: Laurent Vivier --- linux-user/elfload.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 43c16a846d..f6693e5760 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2403,6 +2403,8 @@ static void load_elf_image(const char *image_name, int image_fd, } info->load_bias = load_bias; + info->code_offset = load_bias; + info->data_offset = load_bias; info->load_addr = load_addr; info->entry = ehdr->e_entry + load_bias; info->start_code = -1;