Omar Sandoval b9f174c811 x86/unwind/orc: Add ELF section with ORC version identifier ... Commits ffb1b4a410 ("x86/unwind/orc: Add 'signal' field to ORC metadata") and fb799447ae ("x86,objtool: Split UNWIND_HINT_EMPTY in two") changed the ORC format. Although ORC is internal to the kernel, it's the only way for external tools to get reliable kernel stack traces on x86-64. In particular, the drgn debugger [1] uses ORC for stack unwinding, and these format changes broke it [2]. As the drgn maintainer, I don't care how often or how much the kernel changes the ORC format as long as I have a way to detect the change. It suffices to store a version identifier in the vmlinux and kernel module ELF files (to use when parsing ORC sections from ELF), and in kernel memory (to use when parsing ORC from a core dump+symbol table). Rather than hard-coding a version number that needs to be manually bumped, Peterz suggested hashing the definitions from orc_types.h. If there is a format change that isn't caught by this, the hashing script can be updated. This patch adds an .orc_header allocated ELF section containing the 20-byte hash to vmlinux and kernel modules, along with the corresponding __start_orc_header and __stop_orc_header symbols in vmlinux. 1: https://github.com/osandov/drgn 2: https://github.com/osandov/drgn/issues/303 Fixes: ffb1b4a410 ("x86/unwind/orc: Add 'signal' field to ORC metadata") Fixes: fb799447ae ("x86,objtool: Split UNWIND_HINT_EMPTY in two") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lkml.kernel.org/r/aef9c8dc43915b886a8c48509a12ec1b006ca1ca.1686690801.git.osandov@osandov.com		2023-06-16 17:17:42 +02:00
..
.gitignore	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
devicetable-offsets.c	cdx: add the cdx bus driver	2023-03-29 12:26:32 +02:00
empty.c	Linux-2.6.12-rc2	2005-04-16 15:20:36 -07:00
file2alias.c	cdx: add the cdx bus driver	2023-03-29 12:26:32 +02:00
list.h	modpost: import include/linux/list.h	2022-05-08 03:17:00 +09:00
Makefile	scripts/mod: disable LTO for empty.c	2021-01-14 08:21:09 -08:00
mk_elfconfig.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
modpost.c	x86/unwind/orc: Add ELF section with ORC version identifier	2023-06-16 17:17:42 +02:00
modpost.h	modpost: refactor get_secindex()	2022-08-03 22:56:46 +09:00
sumversion.c	modpost: fix array_size.cocci warning	2022-11-21 10:18:39 +09:00