kernel/tools/objtool/check.h, branch linux-rolling-stable

objtool: Rework header include paths

2021-01-14T00:13:14Z

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: Refactor jump table code to support other architectures

2020-09-10T15:43:13Z

The way to identify jump tables and retrieve all the data necessary to handle the different execution branches is not the same on all architectures. In order to be able to add other architecture support, define an arch-dependent function to process jump-tables. Reviewed-by: Miroslav Benes Signed-off-by: Raphael Gault [J.T.: Move arm64 bits out of this patch, Have only one function to find the start of the jump table, for now assume that the jump table format will be the same as x86] Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf

objtool: Make relocation in alternative handling arch dependent

2020-09-10T15:43:13Z

As pointed out by the comment in handle_group_alt(), support of relocation for instructions in an alternative group depends on whether arch specific kernel code handles it. So, let objtool arch specific code decide whether a relocation for the alternative section should be accepted. Reviewed-by: Miroslav Benes Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf

objtool: Define 'struct orc_entry' only when needed

2020-09-01T22:19:12Z

Implementation of ORC requires some definitions that are currently provided by the target architecture headers. Do not depend on these definitions when the orc subcommand is not implemented. This avoid requiring arches with no orc implementation to provide dummy orc definitions. Signed-off-by: Julien Thierry Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf

x86/static_call: Add inline static call implementation for x86-64

2020-09-01T07:58:05Z

Add the inline static call implementation for x86-64. The generated code is identical to the out-of-line case, except we move the trampoline into it's own section. Objtool uses the trampoline naming convention to detect all the call sites. It then annotates those call sites in the .static_call_sites section. During boot (and module init), the call sites are patched to call directly into the destination function. The temporary trampoline is then no longer used. [peterz: merged trampolines, put trampoline in section] Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/20200818135804.864271425@infradead.org

objtool: Rename rela to reloc

2020-06-01T14:40:58Z

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: Enable compilation of objtool for all architectures

2020-05-20T14:17:28Z

Objtool currently only compiles for x86 architectures. This is fine as it presently does not support tooling for other architectures. However, we would like to be able to convert other kernel tools to run as objtool sub commands because they too process ELF object files. This will allow us to convert tools such as recordmcount to use objtool's ELF code. Since much of recordmcount's ELF code is copy-paste code to/from a variety of other kernel tools (look at modpost for example) this means that if we can convert recordmcount we can convert more. We define weak definitions for subcommand entry functions and other weak definitions for shared functions critical to building existing subcommands. These return 127 when the command is missing which signify tools that do not exist on all architectures. In this case the "check" and "orc" tools do not exist on all architectures so we only add them for x86. Future changes adding support for "check", to arm64 for example, can then modify the SUBCMD_CHECK variable when building for arm64. Objtool is not currently wired in to KConfig to be built for other architectures because it's not needed for those architectures and there are no commands it supports other than those for x86. As more command support is enabled on various architectures the necessary KConfig changes can be made (e.g. adding "STACK_VALIDATION") to trigger building objtool. [ jpoimboe: remove aliases, add __weak macro, add error messages ] Cc: Julien Thierry Signed-off-by: Matt Helsley Signed-off-by: Josh Poimboeuf

objtool: Move struct objtool_file into arch-independent header

2020-05-20T13:35:20Z

The objtool_file structure describes the files objtool works on, is used by the check subcommand, and the check.h header is included by the orc subcommands so it's presently used by all subcommands. Since the structure will be useful in all subcommands besides check, and some subcommands may not want to include check.h to get the definition, split the structure out into a new header meant for use by all objtool subcommands. Signed-off-by: Matt Helsley Reviewed-by: Julien Thierry Signed-off-by: Josh Poimboeuf

objtool: Uniquely identify alternative instruction groups

2020-04-30T18:14:31Z

Assign a unique identifier to every alternative instruction group in order to be able to tell which instructions belong to what alternative. [peterz: extracted from a larger patch] Signed-off-by: Alexandre Chartre Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes

objtool: Implement noinstr validation

2020-04-22T08:53:50Z

Validate that any call out of .noinstr.text is in between instr_begin() and instr_end() annotations. This annotation is useful to ensure correct behaviour wrt tracing sensitive code like entry/exit and idle code. When we run code in a sensitive context we want a guarantee no unknown code is ran. Since this validation relies on knowing the section of call destination symbols, we must run it on vmlinux.o instead of on individual object files. Add two options: -d/--duplicate "duplicate validation for vmlinux" -l/--vmlinux "vmlinux.o validation" Where the latter auto-detects when objname ends with "vmlinux.o" and the former will force all validations, also those already done on !vmlinux object files. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Reviewed-by: Alexandre Chartre Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200416115119.106268040@infradead.org Signed-off-by: Ingo Molnar