kernel/linux.git/tools/objtool/special.c, branch v5.12.2

objtool: Rework header include paths

2021-01-14T00:13:14+00:00

Currently objtool headers are being included either by their base name or included via ../ from a parent directory. In case of a base name usage: #include "warn.h" #include "arch_elf.h" it does not make it apparent from which directory the file comes from. To make it slightly better, and actually to avoid name clashes some arch specific files have "arch_" suffix. And files from an arch folder have to revert to including via ../ e.g: #include "../../elf.h" With additional architectures support and the code base growth there is a need for clearer headers naming scheme for multiple reasons: 1. to make it instantly obvious where these files come from (objtool itself / objtool arch|generic folders / some other external files), 2. to avoid name clashes of objtool arch specific headers, potential obtool arch generic headers and the system header files (there is /usr/include/elf.h already), 3. to avoid ../ includes and improve code readability. 4. to give a warm fuzzy feeling to developers who are mostly kernel developers and are accustomed to linux kernel headers arranging scheme. Doesn't this make it instantly obvious where are these files come from? #include #include And doesn't it look nicer to avoid ugly ../ includes? Which also guarantees this is elf.h from the objtool and not /usr/include/elf.h. #include This patch defines and implements new objtool headers arranging scheme. Which is: - all generic headers go to include/objtool (similar to include/linux) - all arch headers go to arch/$(SRCARCH)/include/arch (to get arch prefix). This is similar to linux arch specific "asm/*" headers but we are not abusing "asm" name and calling it what it is. This also helps to prevent name clashes (arch is not used in system headers or kernel exports). To bring objtool to this state the following things are done: 1. current top level tools/objtool/ headers are moved into include/objtool/ subdirectory, 2. arch specific headers, currently only arch/x86/include/ are moved into arch/x86/include/arch/ and were stripped of "arch_" suffix, 3. new -I$(srctree)/tools/objtool/include include path to make includes like possible, 4. rewriting file includes, 5. make git not to ignore include/objtool/ subdirectory. Signed-off-by: Vasily Gorbik Acked-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Signed-off-by: Josh Poimboeuf

objtool: Fix x86 orc generation on big endian cross-compiles

2021-01-14T00:13:13+00:00

Correct objtool orc generation endianness problems to enable fully functional x86 cross-compiles on big endian hardware. Introduce bswap_if_needed() macro, which does a byte swap if target endianness doesn't match the host, i.e. cross-compilation for little endian on big endian and vice versa. The macro is used for conversion of multi-byte values which are read from / about to be written to a target native endianness ELF file. Signed-off-by: Vasily Gorbik Acked-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Signed-off-by: Josh Poimboeuf

objtool: Abstract alternative special case handling

2020-09-10T15:43:13+00:00

Some alternatives associated with a specific feature need to be treated in a special way. Since the features and how to treat them vary from one architecture to another, move the special case handling to arch specific code. Reviewed-by: Miroslav Benes Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf

objtool: Move macros describing structures to arch-dependent code

2020-09-10T15:43:13+00:00

Some macros are defined to describe the size and layout of structures exception_table_entry, jump_entry and alt_instr. These values can vary from one architecture to another. Have the values be defined by arch specific code. Suggested-by: Raphael Gault Reviewed-by: Miroslav Benes Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf

objtool: Rename rela to reloc

2020-06-01T14:40:58+00:00

Before supporting additional relocation types rename the relevant types and functions from "rela" to "reloc". This work be done with the following regex: sed -e 's/struct rela/struct reloc/g' \ -e 's/$[_\*]$rela$s\{0,1\}$/\1reloc\2/g' \ -e 's/tmprela$s\{0,1\}$/tmpreloc\1/g' \ -e 's/relasec/relocsec/g' \ -e 's/rela_list/reloc_list/g' \ -e 's/rela_hash/reloc_hash/g' \ -e 's/add_rela/add_reloc/g' \ -e 's/rela->/reloc->/g' \ -e '/rela[,\.]/{ s/$[^\.>]$rela$[\.,]$/\1reloc\2/g ; }' \ -e 's/rela =/reloc =/g' \ -e 's/relas =/relocs =/g' \ -e 's/relas\[/relocs[/g' \ -e 's/relaname =/relocname =/g' \ -e 's/= rela\;/= reloc\;/g' \ -e 's/= relas\;/= relocs\;/g' \ -e 's/= relaname\;/= relocname\;/g' \ -e 's/, rela)/, reloc)/g' \ -e 's/$[ @]$rela$[ "]$/\1reloc\2/g' \ -e 's/ rela$/ reloc/g' \ -e 's/, relaname/, relocname/g' \ -e 's/sec->rela/sec->reloc/g' \ -e 's/($!\{0,1\}$rela/(\1reloc/g' \ -i \ arch.h \ arch/x86/decode.c \ check.c \ check.h \ elf.c \ elf.h \ orc_gen.c \ special.c Notable exceptions which complicate the regex include gelf_* library calls and standard/expected section names which still use "rela" because they encode the type of relocation expected. Also, keep "rela" in the struct because it encodes a specific type of relocation we currently expect. It will eventually turn into a member of an anonymous union when a susequent patch adds implicit addend, or "rel", relocation support. Signed-off-by: Matt Helsley Signed-off-by: Josh Poimboeuf

objtool: Optimize read_sections()

2020-03-25T17:28:30+00:00

Perf showed that __hash_init() is a significant portion of read_sections(), so instead of doing a per section rela_hash, use an elf-wide rela_hash. Statistics show us there are about 1.1 million relas, so size it accordingly. This reduces the objtool on vmlinux.o runtime to a third, from 15 to 5 seconds. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200324160924.739153726@infradead.org

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13

2019-05-21T09:28:45+00:00

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details [based] [from] [clk] [highbank] [c] you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 355 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Kate Stewart Reviewed-by: Jilayne Lovejoy Reviewed-by: Steve Winslow Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.de Signed-off-by: Greg Kroah-Hartman

objtool: Add UACCESS validation

2019-04-03T09:02:24+00:00

It is important that UACCESS regions are as small as possible; furthermore the UACCESS state is not scheduled, so doing anything that might directly call into the scheduler will cause random code to be ran with UACCESS enabled. Teach objtool too track UACCESS state and warn about any CALL made while UACCESS is enabled. This very much includes the __fentry__() and __preempt_schedule() calls. Note that exceptions _do_ save/restore the UACCESS state, and therefore they can drive preemption. This also means that all exception handlers must have an otherwise redundant UACCESS disable instruction; therefore ignore this warning for !STT_FUNC code (exception handlers are not normal functions). Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

x86/jump_table: Use relative references

2018-09-27T15:56:48+00:00

Similar to the arm64 case, 64-bit x86 can benefit from using relative references rather than absolute ones when emitting struct jump_entry instances. Not only does this reduce the memory footprint of the entries themselves by 33%, it also removes the need for carrying relocation metadata on relocatable builds (i.e., for KASLR) which saves a fair chunk of .init space as well (although the savings are not as dramatic as on arm64) Signed-off-by: Ard Biesheuvel Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: linux-arm-kernel@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: Arnd Bergmann Cc: Heiko Carstens Cc: Kees Cook Cc: Will Deacon Cc: Catalin Marinas Cc: Steven Rostedt Cc: Martin Schwidefsky Cc: Jessica Yu Link: https://lkml.kernel.org/r/20180919065144.25010-7-ard.biesheuvel@linaro.org

objtool: Implement stack validation 2.0

2017-06-30T08:19:19+00:00

This is a major rewrite of objtool. Instead of only tracking frame pointer changes, it now tracks all stack-related operations, including all register saves/restores. In addition to making stack validation more robust, this also paves the way for undwarf generation. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Jiri Slaby Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/678bd94c0566c6129bcc376cddb259c4c5633004.1498659915.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar