For CONFIG_LTO_CLANG=y, the objtool processing is not possible at the
compilation, hence postponed by the link time.
Reuse $(cmd_objtool) for CONFIG_LTO_CLANG=y by defining objtool-enabled
properly.
For CONFIG_LTO_CLANG=y:
objtool-enabled is off for %.o compilation
objtool-enabled is on for %.lto link
For CONFIG_LTO_CLANG=n:
objtool-enabled is on for %.o compilation
(but, it depends on OBJECT_FILE_NON_STANDARD)
Set part-of-module := y for %.lto.o to avoid repeating --module.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Redo commit 8852c55240 ("kbuild: Fix objtool dependency for
'OBJECT_FILES_NON_STANDARD_<obj> := n'") to add the objtool
dependency in a cleaner way.
Using .SECONDEXPANSION ends up with unreadable code due to escaped
dollars. Also, it is not efficient because the second half of
Makefile.build is parsed twice every time.
Append the objtool dependency to the *.cmd files at the build time.
This is what fixdep and gen_ksymdeps.sh already do. So, following the
same pattern seems a natural solution.
This allows us to drop $$(objtool_dep) entirely.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
objtool_dep includes include/config/{ORC_UNWINDER,STACK_VALIDATION}
so that all the objects are rebuilt when CONFIG_ORC_UNWINDER or
CONFIG_STACK_VALIDATION is toggled.
BTW, the correct option name is not CONFIG_ORC_UNWINDER, but
CONFIG_UNWINDER_ORC. Commit 11af847446 ("x86/unwind: Rename
unwinder config options to 'CONFIG_UNWINDER_*'") missed to
adjust this part. So, this dependency has been broken for a
long time.
As you can see in 'objtool_args', there are more CONFIG options
that affect the objtool command line.
Adding more and more include/config/* is ugly and unmaintainable.
Another issue is that non-standard objects are needlessly rebuilt.
Objects specified as OBJECT_FILES_NON_STANDARD is not processed by
objtool, but they are rebuilt anyway when CONFIG_STACK_VALIDATION
is toggled. This is not a big deal, but better to fix.
A cleaner and more precise fix is to include the objtool command in
*.cmd files so any command change is naturally detected by if_change.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Rename __objtool_obj to objtool, and move it out of the
'ifndef CONFIG_LTO_CLANG' conditional, so it can be used for
cmd_cc_lto_link_modules as well.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Commit b1a1a1a09b ("kbuild: lto: postpone objtool") moved objtool_args
to Makefile.lib, so the arguments can be used in Makefile.modfinal as
well as Makefile.build.
With commit 850ded46c6 ("kbuild: Fix TRIM_UNUSED_KSYMS with
LTO_CLANG"), module LTO linking came back to scripts/Makefile.build
again.
So, there is no more reason to keep objtool_args in a separate file.
Get it back to the original place, close to the objtool command.
Remove the stale comment too.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Searching for symlinks is an expensive operation with the current
logic, as it is at the order of O(n^3). In practice, running the
check spends 2-3 minutes to check all symbols.
Fix it by storing the directory tree into a graph, and using
a Breadth First Search (BFS) to find the links for each sysfs node.
With such improvement, it can now report issues with ~11 seconds
on my machine.
It comes with a price, though: there are more symbols reported
as undefined after this change. I suspect it is due to some
sysfs circular loops that are dropped by BFS. Despite such
increase, it seems that the reports are now more coherent.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/f5c1e7b14a27132821c08f0459ba9aea3ed69028.1631957565.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The search algorithm used inside check_undefined_symbols
has an optimization: it seeks only whats that have the same
leave name. This helps not only to speedup the search, but
it also allows providing a hint about a partial match.
There's a drawback, however: when "what:" finishes with a
wildcard, the logic will skip the what, reporting it as
"not found".
Fix it by grouping the remaining cases altogether, and
disabing any hints for such cases.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/79ba5139643355230e3bba136b20991cfc92020f.1631957565.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull Kbuild fixes from Masahiro Yamada:
- Fix bugs in checkkconfigsymbols.py
- Fix missing sys import in gen_compile_commands.py
- Fix missing FORCE warning for ARCH=sh builds
- Fix -Wignored-optimization-argument warnings for Clang builds
- Turn -Wignored-optimization-argument into an error in order to stop
building instead of sprinkling warnings
* tag 'kbuild-fixes-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: Add -Werror=ignored-optimization-argument to CLANG_FLAGS
x86/build: Do not add -falign flags unconditionally for clang
kbuild: Fix comment typo in scripts/Makefile.modpost
sh: Add missing FORCE prerequisites in Makefile
gen_compile_commands: fix missing 'sys' package
checkkconfigsymbols.py: Remove skipping of help lines in parse_kconfig_file
checkkconfigsymbols.py: Forbid passing 'HEAD' to --commit
Similar to commit 589834b3a0 ("kbuild: Add
-Werror=unknown-warning-option to CLANG_FLAGS").
Clang ignores certain GCC flags that it has not implemented, only
emitting a warning:
$ echo | clang -fsyntax-only -falign-jumps -x c -
clang-14: warning: optimization flag '-falign-jumps' is not supported
[-Wignored-optimization-argument]
When one of these flags gets added to KBUILD_CFLAGS unconditionally, all
subsequent cc-{disable-warning,option} calls fail because -Werror was
added to these invocations to turn the above warning and the equivalent
-W flag warning into errors.
To catch the presence of these flags earlier, turn
-Wignored-optimization-argument into an error so that the flags can
either be implemented or ignored via cc-option and there are no more
weird errors.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Change comment "create one <module>.mod.c file pr. module"
to "create one <module>.mod.c file per module"
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
We need to import the 'sys' package since the script has called
sys.exit() method.
Fixes: 6ad7cbc015 ("Makefile: Add clang-tidy and static analyzer support to makefile")
Signed-off-by: Kortan <kortanzh@gmail.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
When parsing Kconfig files to find symbol definitions and references,
lines after a 'help' line are skipped until a new config definition
starts.
However, Kconfig statements can actually be after a help section, as
long as these have shallower indentation. These are skipped by the
parser.
This means that symbols referenced in this kind of statements are
ignored by this function and thus are not considered undefined
references in case the symbol is not defined.
Remove the 'skip' logic entirely, as it is not needed if we just use the
STMT regex to find the end of help lines.
However, this means that keywords that appear as part of the help
message (i.e. with the same indentation as the help lines) it will be
considered as a reference/definition. This can happen now as well, but
only with REGEX_KCONFIG_DEF lines. Also, the keyword must have a SYMBOL
after it, which probably means that someone referenced a config in the
help so it seems like a bonus :)
The real solution is to keep track of the indentation when a the first
help line in encountered and then handle DEF and STMT lines only if the
indentation is shallower.
Signed-off-by: Ariel Marcovitch <arielmarcovitch@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
As opposed to the --diff option, --commit can get ref names instead of
commit hashes.
When using the --commit option, the script resets the working directory
to the commit before the given ref, by adding '~' to the end of the ref.
However, the 'HEAD' ref is relative, and so when the working directory
is reset to 'HEAD~', 'HEAD' points to what was 'HEAD~'. Then when the
script resets to 'HEAD' it actually stays in the same commit. In this
case, the script won't report any cases because there is no diff between
the cases of the two refs.
Prevent the user from using HEAD refs.
A better solution might be to resolve the refs before doing the
reset, but for now just disallow such refs.
Signed-off-by: Ariel Marcovitch <arielmarcovitch@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Merge patch series from Nick Desaulniers to update the minimum gcc
version to 5.1.
This is some of the left-overs from the merge window that I didn't want
to deal with yesterday, so it comes in after -rc1 but was sent before.
Gcc-4.9 support has been an annoyance for some time, and with -Werror I
had the choice of applying a fairly big patch from Kees Cook to remove a
fair number of initializer warnings (still leaving some), or this patch
series from Nick that just removes the source of the problem.
The initializer cleanups might still be worth it regardless, but
honestly, I preferred just tackling the problem with gcc-4.9 head-on.
We've been more aggressiuve about no longer having to care about
compilers that were released a long time ago, and I think it's been a
good thing.
I added a couple of patches on top to sort out a few left-overs now that
we no longer support gcc-4.x.
As noted by Arnd, as a result of this minimum compiler version upgrade
we can probably change our use of '--std=gnu89' to '--std=gnu11', and
finally start using local loop declarations etc. But this series does
_not_ yet do that.
Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/
Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/
Link: https://github.com/ClangBuiltLinux/linux/issues/1438
* emailed patches from Nick Desaulniers <ndesaulniers@google.com>:
Drop some straggling mentions of gcc-4.9 as being stale
compiler_attributes.h: drop __has_attribute() support for gcc4
vmlinux.lds.h: remove old check for GCC 4.9
compiler-gcc.h: drop checks for older GCC versions
Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround
arm64: remove GCC version check for ARCH_SUPPORTS_INT128
powerpc: remove GCC version check for UPD_CONSTR
riscv: remove Kconfig check for GCC version for ARCH_RV64I
Kconfig.debug: drop GCC 5+ version check for DWARF5
mm/ksm: remove old GCC 4.9+ check
compiler.h: drop fallback overflow checkers
Documentation: raise minimum supported version of GCC to 5.1
commit fad7cd3310 ("nbd: add the check to prevent overflow in
__nbd_ioctl()") raised an issue from the fallback helpers added in
commit f0907827a8 ("compiler.h: enable builtin overflow checkers and
add fallback code")
Specifically, the helpers for checking whether the results of a
multiplication overflowed (__unsigned_mul_overflow,
__signed_add_overflow) use the division operator when
!COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW. This is problematic for 64b
operands on 32b hosts.
Also, because the macro is type agnostic, it is very difficult to write
a similarly type generic macro that dispatches to one of:
* div64_s64
* div64_u64
* div_s64
* div_u64
Raising the minimum supported versions allows us to remove all of the
fallback helpers for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW, instead
dispatching the compiler builtins.
arm64 has already raised the minimum supported GCC version to 5.1, do
this for all targets now. See the link below for the previous
discussion.
Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/
Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/
Link: https://github.com/ClangBuiltLinux/linux/issues/1438
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The exception table entries contain the instruction address, the fixup
address and the handler address. All addresses are relative. Storing the
handler address has a few downsides:
1) Most handlers need to be exported
2) Handlers can be defined everywhere and there is no overview about the
handler types
3) MCE needs to check the handler type to decide whether an in kernel #MC
can be recovered. The functionality of the handler itself is not in any
way special, but for these checks there need to be separate functions
which in the worst case have to be exported.
Some of these 'recoverable' exception fixups are pretty obscure and
just reuse some other handler to spare code. That obfuscates e.g. the
#MC safe copy functions. Cleaning that up would require more handlers
and exports
Rework the exception fixup mechanics by storing a fixup type number instead
of the handler address and invoke the proper handler for each fixup
type. Also teach the extable sort to leave the type field alone.
This makes most handlers static except for special cases like the MCE
MSR fixup and the BPF fixup. This allows to add more types for cleaning up
the obscure places without adding more handler code and exports.
There is a marginal code size reduction for a production config and it
removes _eight_ exported symbols.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lkml.kernel.org/r/20210908132525.211958725@linutronix.de
Mauro Carvalho Chehab
Masahiro Yamada
Rob Herring
Linus Torvalds
Nathan Chancellor
Ramji Jiyani
Kortan
Ariel Marcovitch
Philip K. Gisslow
Nick Desaulniers
Thomas Gleixner