Split the existing options into two groups: actions, which actually do
something; and options, which modify the actions in some way.
Also there's no need to have short flags for all the non-action options.
Reserve short flags for the more important actions.
While at it:
- change a few of the short flags to be more intuitive
- make option descriptions more consistently descriptive
- sort options in the source like they are when printed
- move options to a global struct
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/9dcaa752f83aca24b1b21f0b0eeb28a0c181c0b0.1650300597.git.jpoimboe@redhat.com
With IBT support in, objtool is now fully capable of following vmlinux
code flow in LTO mode. Start reporting unreachable warnings for Clang
LTO as well.
Fixes: ed53a0d971 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/7b12df54bceeb0761fe9fc8269ea0c00501214a9.1650300597.git.jpoimboe@redhat.com
The two commits
d8d2d38275 ("kbuild: remove PYTHON variable")
a8cccdd954 ("init: lto: ensure initcall ordering")
were applied in the same development cycle, into two different trees.
After they were merged together, this ${PYTHON} expands to an empty
string.
Therefore, ${srctree}/scripts/jobserver-exec is executed directly.
(it has the executable bit set)
This is working but let's fix the code into the intended form.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Objtool's --ibt option generates .ibt_endbr_seal which lists
superfluous ENDBR instructions. That is those instructions for which
the function is never indirectly called.
Overwrite these ENDBR instructions with a NOP4 such that these
function can never be indirect called, reducing the number of viable
ENDBR targets in the kernel.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org
In order to prepare for LTO like objtool runs for modules, rename the
duplicate argument to lto.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.172584233@infradead.org
- Add new kconfig target 'make mod2noconfig', which will be useful to
speed up the build and test iteration.
- Raise the minimum supported version of LLVM to 11.0.0
- Refactor certs/Makefile
- Change the format of include/config/auto.conf to stop double-quoting
string type CONFIG options.
- Fix ARCH=sh builds in dash
- Separate compression macros for general purposes (cmd_bzip2 etc.) and
the ones for decompressors (cmd_bzip2_with_size etc.)
- Misc Makefile cleanups
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Merge tag 'kbuild-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Add new kconfig target 'make mod2noconfig', which will be useful to
speed up the build and test iteration.
- Raise the minimum supported version of LLVM to 11.0.0
- Refactor certs/Makefile
- Change the format of include/config/auto.conf to stop double-quoting
string type CONFIG options.
- Fix ARCH=sh builds in dash
- Separate compression macros for general purposes (cmd_bzip2 etc.) and
the ones for decompressors (cmd_bzip2_with_size etc.)
- Misc Makefile cleanups
* tag 'kbuild-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
kbuild: add cmd_file_size
arch: decompressor: remove useless vmlinux.bin.all-y
kbuild: rename cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}
kbuild: drop $(size_append) from cmd_zstd
sh: rename suffix-y to suffix_y
doc: kbuild: fix default in `imply` table
microblaze: use built-in function to get CPU_{MAJOR,MINOR,REV}
certs: move scripts/extract-cert to certs/
kbuild: do not quote string values in include/config/auto.conf
kbuild: do not include include/config/auto.conf from shell scripts
certs: simplify $(srctree)/ handling and remove config_filename macro
kbuild: stop using config_filename in scripts/Makefile.modsign
certs: remove misleading comments about GCC PR
certs: refactor file cleaning
certs: remove unneeded -I$(srctree) option for system_certificates.o
certs: unify duplicated cmd_extract_certs and improve the log
certs: use $< and $@ to simplify the key generation rule
kbuild: remove headers_check stub
kbuild: move headers_check.pl to usr/include/
certs: use if_changed to re-generate the key when the key type is changed
...
New:
- The Real Time Linux Analysis (RTLA) tool is added to the tools directory.
- Can safely filter on user space pointers with: field.ustring ~ "match-string"
- eprobes can now be filtered like any other event.
- trace_marker(_raw) now uses stream_open() to allow multiple threads to safely
write to it. Note, this could possibly break existing user space, but we will
not know until we hear about it, and then can revert the change if need be.
- New field in events to display when bottom halfs are disabled.
- Sorting of the ftrace functions are now done at compile time instead of
at bootup.
Infrastructure changes to support future efforts:
- Added __rel_loc type for trace events. Similar to __data_loc but the offset
to the dynamic data is based off of the location of the descriptor and not
the beginning of the event. Needed for user defined events.
- Some simplification of event trigger code.
- Make synthetic events process its callback better to not hinder other
event callbacks that are registered. Needed for user defined events.
And other small fixes and clean ups.
-
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Merge tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New:
- The Real Time Linux Analysis (RTLA) tool is added to the tools
directory.
- Can safely filter on user space pointers with: field.ustring ~
"match-string"
- eprobes can now be filtered like any other event.
- trace_marker(_raw) now uses stream_open() to allow multiple threads
to safely write to it. Note, this could possibly break existing
user space, but we will not know until we hear about it, and then
can revert the change if need be.
- New field in events to display when bottom halfs are disabled.
- Sorting of the ftrace functions are now done at compile time
instead of at bootup.
Infrastructure changes to support future efforts:
- Added __rel_loc type for trace events. Similar to __data_loc but
the offset to the dynamic data is based off of the location of the
descriptor and not the beginning of the event. Needed for user
defined events.
- Some simplification of event trigger code.
- Make synthetic events process its callback better to not hinder
other event callbacks that are registered. Needed for user defined
events.
And other small fixes and cleanups"
* tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits)
tracing: Add ustring operation to filtering string pointers
rtla: Add rtla timerlat hist documentation
rtla: Add rtla timerlat top documentation
rtla: Add rtla timerlat documentation
rtla: Add rtla osnoise hist documentation
rtla: Add rtla osnoise top documentation
rtla: Add rtla osnoise man page
rtla: Add Documentation
rtla/timerlat: Add timerlat hist mode
rtla: Add timerlat tool and timelart top mode
rtla/osnoise: Add the hist mode
rtla/osnoise: Add osnoise top mode
rtla: Add osnoise tool
rtla: Helper functions for rtla
rtla: Real-Time Linux Analysis tool
tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails
tracing: Remove duplicate warnings when calling trace_create_file()
tracing/kprobes: 'nmissed' not showed correctly for kretprobe
tracing: Add test for user space strings when filtering on string pointers
tracing: Have syscall trace events use trace_event_buffer_lock_reserve()
...
When the kernel starts, the initialization of ftrace takes
up a portion of the time (approximately 6~8ms) to sort mcount
addresses. We can save this time by moving mcount-sorting to
compile time.
Link: https://lkml.kernel.org/r/20211212113358.34208-2-yinan@linux.alibaba.com
Signed-off-by: Yinan Liu <yinan@linux.alibaba.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Richard Weinberger pointed out the risk of sourcing the kernel config
from shell scripts [1], and proposed some patches [2], [3]. It is a good
point, but it took a long time because I was wondering how to fix this.
This commit goes with simple grep approach because there are only a few
scripts including the kernel configuration.
scripts/link_vmlinux.sh has references to a bunch of CONFIG options,
all of which are boolean. I added is_enabled() helper as
scripts/package/{mkdebian,builddeb} do.
scripts/gen_autoksyms.sh uses 'eval', stating "to expand the whitelist
path". I removed it since it is the issue we are trying to fix.
I was a bit worried about the cost of invoking the grep command over
again. I extracted the grep parts from it, and measured the cost. It
was approximately 0.03 sec, which I hope is acceptable.
[test code]
$ cat test-grep.sh
#!/bin/sh
is_enabled() {
grep -q "^$1=y" include/config/auto.conf
}
is_enabled CONFIG_LTO_CLANG
is_enabled CONFIG_LTO_CLANG
is_enabled CONFIG_STACK_VALIDATION
is_enabled CONFIG_UNWINDER_ORC
is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
is_enabled CONFIG_VMLINUX_VALIDATION
is_enabled CONFIG_FRAME_POINTER
is_enabled CONFIG_GCOV_KERNEL
is_enabled CONFIG_LTO_CLANG
is_enabled CONFIG_RETPOLINE
is_enabled CONFIG_X86_SMAP
is_enabled CONFIG_LTO_CLANG
is_enabled CONFIG_VMLINUX_MAP
is_enabled CONFIG_KALLSYMS_ALL
is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU
is_enabled CONFIG_KALLSYMS_BASE_RELATIVE
is_enabled CONFIG_DEBUG_INFO_BTF
is_enabled CONFIG_KALLSYMS
is_enabled CONFIG_DEBUG_INFO_BTF
is_enabled CONFIG_BPF
is_enabled CONFIG_BUILDTIME_TABLE_SORT
is_enabled CONFIG_KALLSYMS
$ time ./test-grep.sh
real 0m0.036s
user 0m0.027s
sys m0.009s
[1]: https://lore.kernel.org/all/1919455.eZKeABUfgV@blindfold/
[2]: https://lore.kernel.org/all/20180219092245.26404-1-richard@nod.at/
[3]: https://lore.kernel.org/all/20210920213957.1064-2-richard@nod.at/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
- Remove the global -isystem compiler flag, which was made possible by
the introduction of <linux/stdarg.h>
- Improve the Kconfig help to print the location in the top menu level
- Fix "FORCE prerequisite is missing" build warning for sparc
- Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which generate
a zstd-compressed tarball
- Prevent gen_init_cpio tool from generating a corrupted cpio when
KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later
- Misc cleanups
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Merge tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Remove the global -isystem compiler flag, which was made possible by
the introduction of <linux/stdarg.h>
- Improve the Kconfig help to print the location in the top menu level
- Fix "FORCE prerequisite is missing" build warning for sparc
- Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which
generate a zstd-compressed tarball
- Prevent gen_init_cpio tool from generating a corrupted cpio when
KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later
- Misc cleanups
* tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
kbuild: use more subdir- for visiting subdirectories while cleaning
sh: remove meaningless archclean line
initramfs: Check timestamp to prevent broken cpio archive
kbuild: split DEBUG_CFLAGS out to scripts/Makefile.debug
gen_init_cpio: add static const qualifiers
kbuild: Add make tarzst-pkg build option
scripts: update the comments of kallsyms support
sparc: Add missing "FORCE" target when using if_changed
kconfig: refactor conf_touch_dep()
kconfig: refactor conf_write_dep()
kconfig: refactor conf_write_autoconf()
kconfig: add conf_get_autoheader_name()
kconfig: move sym_escape_string_value() to confdata.c
kconfig: refactor listnewconfig code
kconfig: refactor conf_write_symbol()
kconfig: refactor conf_write_heading()
kconfig: remove 'const' from the return type of sym_escape_string_value()
kconfig: rename a variable in the lexer to a clearer name
kconfig: narrow the scope of variables in the lexer
kconfig: Create links to main menu items in search
...
Using new PAHOLE_FLAGS variable to pass extra arguments to
pahole for both vmlinux and modules BTF data generation.
Adding new scripts/pahole-flags.sh script that detect and
prints pahole options.
[ fixed issues found by kernel test robot ]
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211029125729.70002-1-jolsa@kernel.org
update the comments of kallsyms support.
Fixes: af73d78bd3 ("kbuild: Remove debug info from kallsyms linking")
Signed-off-by: Hui Su <suhui_kernel@163.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
For ARCH=um, ${CC} is used as the linker driver. Hence, the linker
options are prefixed with -Wl, .
Merge the similar code.
I replaced the -T option with the long option --script= so that it
works well with/without ${wl}.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
arch/um/Makefile passes the -f option to the ln command:
linux: vmlinux
@echo ' LINK $@'
$(Q)ln -f $< $@
So, the hard link is always re-created, and the old one is removed
anyway.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
When Clang LTO is enabled, vmlinux_link() reuses vmlinux.o instead of
re-linking ${KBUILD_VMLINUX_OBJS} and ${KBUILD_VMLINUX_LIBS}.
That is the only difference here, so merge the similar code.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
- Increase the -falign-functions alignment for the debug option.
- Remove ugly libelf checks from the top Makefile.
- Make the silent build (-s) more silent.
- Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.
- Various script cleanups
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Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Increase the -falign-functions alignment for the debug option.
- Remove ugly libelf checks from the top Makefile.
- Make the silent build (-s) more silent.
- Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.
- Various script cleanups
* tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits)
scripts: add generic syscallnr.sh
scripts: check duplicated syscall number in syscall table
sparc: syscalls: use pattern rules to generate syscall headers
parisc: syscalls: use pattern rules to generate syscall headers
nds32: add arch/nds32/boot/.gitignore
kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
kbuild: modpost: Explicitly warn about unprototyped symbols
kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
kconfig.h: explain IS_MODULE(), IS_ENABLED()
kconfig: constify long_opts
scripts/setlocalversion: simplify the short version part
scripts/setlocalversion: factor out 12-chars hash construction
scripts/setlocalversion: add more comments to -dirty flag detection
scripts/setlocalversion: remove workaround for old make-kpkg
scripts/setlocalversion: remove mercurial, svn and git-svn supports
kbuild: clean up ${quiet} checks in shell scripts
kbuild: sink stdout from cmd for silent build
init: use $(call cmd,) for generating include/generated/compile.h
kbuild: merge scripts/mkmakefile to top Makefile
sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild
...
Commit "mm/page_alloc: convert per-cpu list protection to local_lock" will
introduce a zero-sized per-CPU variable, which causes pahole to generate
invalid BTF. Only pahole versions 1.18 through 1.21 are impacted, as
before 1.18 pahole doesn't know anything about per-CPU variables, and 1.22
contains the proper fix for the issue.
Luckily, pahole 1.18 got --skip_encoding_btf_vars option disabling BTF
generation for per-CPU variables in anticipation of some unanticipated
problems. So use this escape hatch to disable per-CPU var BTF info on
those problematic pahole versions. Users relying on availability of
per-CPU var BTFs would need to upgrade to pahole 1.22+, but everyone won't
notice any regressions.
Link: https://lkml.kernel.org/r/20210530002536.3193829-1-andrii@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ccache tool can be used to speed up cross-compilation, by calling the
compiler and binutils through ccache. For example, following should work:
$ export ARCH=arm64 CROSS_COMPILE="ccache aarch64-linux-gnu-"
$ make M=drivers/gpu/drm/rockchip/
but pahole fails to extract the BTF info from DWARF, breaking the build:
CC [M] drivers/gpu/drm/rockchip//rockchipdrm.mod.o
LD [M] drivers/gpu/drm/rockchip//rockchipdrm.ko
BTF [M] drivers/gpu/drm/rockchip//rockchipdrm.ko
aarch64-linux-gnu-objcopy: invalid option -- 'J'
Usage: aarch64-linux-gnu-objcopy [option(s)] in-file [out-file]
Copies a binary file, possibly transforming it in the process
...
make[1]: *** [scripts/Makefile.modpost:156: __modpost] Error 2
make: *** [Makefile:1866: modules] Error 2
this fails because OBJCOPY is set to "ccache aarch64-linux-gnu-copy" and
later pahole is executed with the following command line:
LLVM_OBJCOPY=$(OBJCOPY) $(PAHOLE) -J --btf_base vmlinux $@
which gets expanded to:
LLVM_OBJCOPY=ccache aarch64-linux-gnu-objcopy pahole -J ...
instead of:
LLVM_OBJCOPY="ccache aarch64-linux-gnu-objcopy" pahole -J ...
Fixes: 5f9ae91f7c ("kbuild: Build kernel module BTFs if BTF is enabled and pahole supports it")
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/bpf/20210526215228.3729875-1-javierm@redhat.com
There were efforts to make 'make -s' really silent when it is a
warning-free build.
The conventional way was to let a shell script check ${quiet}, and if
it is 'silent_', suppress the stdout by itself.
With the previous commit, the 'cmd' takes care of it now. The 'cmd' is
also invoked from if_changed, if_changed_dep, and if_changed_rule.
You can omit ${quiet} checks in shell scripts when they are invoked
from the 'cmd' macro.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Keep them around until they are cleaned up by make clean. This
uses a bit more disk space, but makes it easier to debug any
problems with the kernel link process.
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
- Evaluate $(call cc-option,...) etc. only for build targets
- Add CONFIG_VMLINUX_MAP to generate .map file when linking vmlinux
- Remove unnecessary --gcc-toolchains Clang flag because the --prefix
flag finds the toolchains
- Do not pass Clang's --prefix flag when using the integrated as
- Check the assembler version in Kconfig time
- Add new CONFIG options, AS_VERSION, AS_IS_GNU, AS_IS_LLVM to clean up
some dependencies in Kconfig
- Fix invalid Module.symvers creation when building only modules without
vmlinux
- Fix false-positive modpost warnings when CONFIG_TRIM_UNUSED_KSYMS is
set, but there is no module to build
- Refactor module installation Makefile
- Support zstd for module compression
- Convert alpha and ia64 to use generic shell scripts to generate the
syscall headers
- Add a new elfnote to indicate if the kernel was built with LTO, which
will be used by pahole
- Flatten the directory structure under include/config/ so CONFIG options
and filenames match
- Change the deb source package name from linux-$(KERNELRELEASE) to
linux-upstream
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Merge tag 'kbuild-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Evaluate $(call cc-option,...) etc. only for build targets
- Add CONFIG_VMLINUX_MAP to generate .map file when linking vmlinux
- Remove unnecessary --gcc-toolchains Clang flag because the --prefix
flag finds the toolchains
- Do not pass Clang's --prefix flag when using the integrated as
- Check the assembler version in Kconfig time
- Add new CONFIG options, AS_VERSION, AS_IS_GNU, AS_IS_LLVM to clean up
some dependencies in Kconfig
- Fix invalid Module.symvers creation when building only modules
without vmlinux
- Fix false-positive modpost warnings when CONFIG_TRIM_UNUSED_KSYMS is
set, but there is no module to build
- Refactor module installation Makefile
- Support zstd for module compression
- Convert alpha and ia64 to use generic shell scripts to generate the
syscall headers
- Add a new elfnote to indicate if the kernel was built with LTO, which
will be used by pahole
- Flatten the directory structure under include/config/ so CONFIG
options and filenames match
- Change the deb source package name from linux-$(KERNELRELEASE) to
linux-upstream
* tag 'kbuild-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (42 commits)
kbuild: Add $(KBUILD_HOSTLDFLAGS) to 'has_libelf' test
kbuild: deb-pkg: change the source package name to linux-upstream
tools: do not include scripts/Kbuild.include
kbuild: redo fake deps at include/config/*.h
kbuild: remove TMPO from try-run
MAINTAINERS: add pattern for dummy-tools
kbuild: add an elfnote for whether vmlinux is built with lto
ia64: syscalls: switch to generic syscallhdr.sh
ia64: syscalls: switch to generic syscalltbl.sh
alpha: syscalls: switch to generic syscallhdr.sh
alpha: syscalls: switch to generic syscalltbl.sh
sysctl: use min() helper for namecmp()
kbuild: add support for zstd compressed modules
kbuild: remove CONFIG_MODULE_COMPRESS
kbuild: merge scripts/Makefile.modsign to scripts/Makefile.modinst
kbuild: move module strip/compression code into scripts/Makefile.modinst
kbuild: refactor scripts/Makefile.modinst
kbuild: rename extmod-prefix to extmod_prefix
kbuild: check module name conflict for external modules as well
kbuild: show the target directory for depmod log
...
The patch adding CONFIG_VMLINUX_MAP revealed a small defect in the
build system: link-vmlinux.sh takes decisions based on CONFIG_*
options, but changing one of those does not always lead to vmlinux
being linked again.
For most of the CONFIG_* knobs referenced previously, this has
probably been hidden by those knobs also affecting some object file,
hence indirectly also vmlinux.
But CONFIG_VMLINUX_MAP is only handled inside link-vmlinux.sh, and
changing CONFIG_VMLINUX_MAP=n to CONFIG_VMLINUX_MAP=y does not cause
the build system to re-link (and hence have vmlinux.map
emitted). Since that map file is mostly a debugging aid, this is
merely a nuisance which is easily worked around by just deleting
vmlinux and building again.
But one could imagine other (possibly future) CONFIG options that
actually do affect the vmlinux binary but which are not captured
through some object file dependency.
To fix this, make link-vmlinux.sh emit a .vmlinux.d file in the same
format as the dependency files generated by gcc, and apply the fixdep
logic to that. I've tested that this correctly works with both in-tree
and out-of-tree builds.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
It can be quite useful to have ld emit a link map file, in order to
debug or verify that special sections end up where they are supposed
to, and to see what LD_DEAD_CODE_DATA_ELIMINATION manages to get rid
of.
The only reason I'm not just adding this unconditionally is that the
.map file can be rather large (several MB), and that's a waste of
space when one isn't interested in these things. Also make it depend
on CONFIG_EXPERT.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
pahole v1.21 supports the --btf_gen_floats flag, which makes it
generate the information about the floating-point types [1].
Adjust link-vmlinux.sh to pass this flag to pahole in case it's
supported, which is determined using a simple version check.
[1] https://lore.kernel.org/dwarves/YHRiXNX1JUF2Az0A@kernel.org/
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210413190043.21918-1-iii@linux.ibm.com
With LTO, LLVM bitcode won't be compiled into native code until
modpost_link, or modfinal for modules. This change postpones calls
to objtool until after these steps, and moves objtool_args to
Makefile.lib, so the arguments can be reused in Makefile.modfinal.
As we didn't have objects to process earlier, we use --duplicate
when processing vmlinux.o. This change also disables unreachable
instruction warnings with LTO to avoid warnings about the int3
padding between functions.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
This change adds a --noinstr flag to objtool to allow us to specify
that we're processing vmlinux.o without also enabling noinstr
validation. This is needed to avoid false positives with LTO when we
run objtool on vmlinux.o without CONFIG_DEBUG_ENTRY.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
With LTO, we run objtool on vmlinux.o, but don't want noinstr
validation. This change requires --vmlinux to be passed to objtool
explicitly.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
With LTO, the compiler doesn't necessarily obey the link order for
initcalls, and initcall variables need globally unique names to avoid
collisions at link time.
This change exports __KBUILD_MODNAME and adds the initcall_id() macro,
which uses it together with __COUNTER__ and __LINE__ to help ensure
these variables have unique names, and moves each variable to its own
section when LTO is enabled, so the correct order can be specified using
a linker script.
The generate_initcall_ordering.pl script uses nm to find initcalls from
the object files passed to the linker, and generates a linker script
that specifies the same order for initcalls that we would have without
LTO. With LTO enabled, the script is called in link-vmlinux.sh through
jobserver-exec to limit the number of jobs spawned.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-8-samitolvanen@google.com
With CONFIG_MODVERSIONS, version information is linked into each
compilation unit that exports symbols. With LTO, we cannot use this
method as all C code is compiled into LLVM bitcode instead. This
change collects symbol versions into .symversions files and merges
them in link-vmlinux.sh where they are all linked into vmlinux.o at
the same time.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-4-samitolvanen@google.com
This change adds build system support for Clang's Link Time
Optimization (LTO). With -flto, instead of ELF object files, Clang
produces LLVM bitcode, which is compiled into native code at link
time, allowing the final binary to be optimized globally. For more
details, see:
https://llvm.org/docs/LinkTimeOptimization.html
The Kconfig option CONFIG_LTO_CLANG is implemented as a choice,
which defaults to LTO being disabled. To use LTO, the architecture
must select ARCH_SUPPORTS_LTO_CLANG and support:
- compiling with Clang,
- compiling all assembly code with Clang's integrated assembler,
- and linking with LLD.
While using CONFIG_LTO_CLANG_FULL results in the best runtime
performance, the compilation is not scalable in time or
memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows
parallel optimization and faster incremental builds. ThinLTO is
used by default if the architecture also selects
ARCH_SUPPORTS_LTO_CLANG_THIN:
https://clang.llvm.org/docs/ThinLTO.html
To enable LTO, LLVM tools must be used to handle bitcode files, by
passing LLVM=1 and LLVM_IAS=1 options to make:
$ make LLVM=1 LLVM_IAS=1 defconfig
$ scripts/config -e LTO_CLANG_THIN
$ make LLVM=1 LLVM_IAS=1
To prepare for LTO support with other compilers, common parts are
gated behind the CONFIG_LTO option, and LTO can be disabled for
specific files by filtering out CC_FLAGS_LTO.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
- Support 'make compile_commands.json' to generate the compilation
database more easily, avoiding stale entries
- Support 'make clang-analyzer' and 'make clang-tidy' for static checks
using clang-tidy
- Preprocess scripts/modules.lds.S to allow CONFIG options in the module
linker script
- Drop cc-option tests from compiler flags supported by our minimal
GCC/Clang versions
- Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y
- Use sha1 build id for both BFD linker and LLD
- Improve deb-pkg for reproducible builds and rootless builds
- Remove stale, useless scripts/namespace.pl
- Turn -Wreturn-type warning into error
- Fix build error of deb-pkg when CONFIG_MODULES=n
- Replace 'hostname' command with more portable 'uname -n'
- Various Makefile cleanups
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Merge tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Support 'make compile_commands.json' to generate the compilation
database more easily, avoiding stale entries
- Support 'make clang-analyzer' and 'make clang-tidy' for static checks
using clang-tidy
- Preprocess scripts/modules.lds.S to allow CONFIG options in the
module linker script
- Drop cc-option tests from compiler flags supported by our minimal
GCC/Clang versions
- Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y
- Use sha1 build id for both BFD linker and LLD
- Improve deb-pkg for reproducible builds and rootless builds
- Remove stale, useless scripts/namespace.pl
- Turn -Wreturn-type warning into error
- Fix build error of deb-pkg when CONFIG_MODULES=n
- Replace 'hostname' command with more portable 'uname -n'
- Various Makefile cleanups
* tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
kbuild: Use uname for LINUX_COMPILE_HOST detection
kbuild: Only add -fno-var-tracking-assignments for old GCC versions
kbuild: remove leftover comment for filechk utility
treewide: remove DISABLE_LTO
kbuild: deb-pkg: clean up package name variables
kbuild: deb-pkg: do not build linux-headers package if CONFIG_MODULES=n
kbuild: enforce -Werror=return-type
scripts: remove namespace.pl
builddeb: Add support for all required debian/rules targets
builddeb: Enable rootless builds
builddeb: Pass -n to gzip for reproducible packages
kbuild: split the build log of kallsyms
kbuild: explicitly specify the build id style
scripts/setlocalversion: make git describe output more reliable
kbuild: remove cc-option test of -Werror=date-time
kbuild: remove cc-option test of -fno-stack-check
kbuild: remove cc-option test of -fno-strict-overflow
kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles
kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan
kbuild: do not create built-in objects for external module builds
...
Currently, the build log shows KSYM + object name.
Precisely speaking, kallsyms generates a .S file and then the compiler
compiles it into a .o file. Split the build log into two.
[Before]
GEN modules.builtin
LD .tmp_vmlinux.kallsyms1
KSYM .tmp_vmlinux.kallsyms1.o
LD .tmp_vmlinux.kallsyms2
KSYM .tmp_vmlinux.kallsyms2.o
LD vmlinux
[After]
GEN modules.builtin
LD .tmp_vmlinux.kallsyms1
KSYMS .tmp_vmlinux.kallsyms1.S
AS .tmp_vmlinux.kallsyms1.o
LD .tmp_vmlinux.kallsyms2
KSYMS .tmp_vmlinux.kallsyms2.S
AS .tmp_vmlinux.kallsyms2.o
LD vmlinux
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Currently all the resolve_btfids 'users' are under CONFIG_BPF
code, so if we have CONFIG_BPF disabled, resolve_btfids will
fail, because there's no data to resolve.
Disabling resolve_btfids if there's CONFIG_BPF disabled,
so we won't fail such builds.
Suggested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200923185735.3048198-1-jolsa@kernel.org
- run the checker (e.g. sparse) after the compiler
- remove unneeded cc-option tests for old compiler flags
- fix tar-pkg to install dtbs
- introduce ccflags-remove-y and asflags-remove-y syntax
- allow to trace functions in sub-directories of lib/
- introduce hostprogs-always-y and userprogs-always-y syntax
- various Makefile cleanups
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Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- run the checker (e.g. sparse) after the compiler
- remove unneeded cc-option tests for old compiler flags
- fix tar-pkg to install dtbs
- introduce ccflags-remove-y and asflags-remove-y syntax
- allow to trace functions in sub-directories of lib/
- introduce hostprogs-always-y and userprogs-always-y syntax
- various Makefile cleanups
* tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base
kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled
kbuild: introduce hostprogs-always-y and userprogs-always-y
kbuild: sort hostprogs before passing it to ifneq
kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
kbuild: Replace HTTP links with HTTPS ones
kbuild: trace functions in subdirectories of lib/
kbuild: introduce ccflags-remove-y and asflags-remove-y
kbuild: do not export LDFLAGS_vmlinux
kbuild: always create directories of targets
powerpc/boot: add DTB to 'targets'
kbuild: buildtar: add dtbs support
kbuild: remove cc-option test of -ffreestanding
kbuild: remove cc-option test of -fno-stack-protector
Revert "kbuild: Create directory for target DTB"
kbuild: run the checker after the compiler
When you clean the build tree for ARCH=arm, you may see the following
error message from 'nm' command:
$ make -j24 ARCH=arm clean
CLEAN arch/arm/crypto
CLEAN arch/arm/kernel
CLEAN arch/arm/mach-at91
CLEAN arch/arm/mach-omap2
CLEAN arch/arm/vdso
CLEAN certs
CLEAN lib
CLEAN usr
CLEAN net/wireless
CLEAN drivers/firmware/efi/libstub
nm: 'arch/arm/boot/compressed/../../../../vmlinux': No such file
/bin/sh: 1: arithmetic expression: expecting primary: " "
CLEAN arch/arm/boot/compressed
CLEAN drivers/scsi
CLEAN drivers/tty/vt
CLEAN arch/arm/boot
CLEAN vmlinux.symvers modules.builtin modules.builtin.modinfo
Even if you rerun the same command, the error message will not be
shown despite vmlinux is already gone.
To reproduce it, the parallel option -j is needed. Single thread
cleaning always executes 'archclean', 'vmlinuxclean' in this order,
so vmlinux still exists when arch/arm/boot/compressed/ is cleaned.
Looking at arch/arm/boot/compressed/Makefile does not help understand
the reason of the error message. Both KBSS_SZ and LDFLAGS_vmlinux are
assigned with '=' operator, hence, they are not expanded unless used.
Obviously, 'make clean' does not use them.
In fact, the root cause exists in the top Makefile:
export LDFLAGS_vmlinux
Since LDFLAGS_vmlinux is an exported variable, LDFLAGS_vmlinux in
arch/arm/boot/compressed/Makefile is expanded when scripts/Makefile.clean
has a command to execute. This is why the error message shows up only
when there exist build artifacts in arch/arm/boot/compressed/.
Adding 'unexport LDFLAGS_vmlinux' to arch/arm/boot/compressed/Makefile
will fix it as far as ARCH=arm is concerned, but I think the proper fix
is to get rid of 'export LDFLAGS_vmlinux' from the top Makefile.
LDFLAGS_vmlinux in the top Makefile contains linker flags for the top
vmlinux. LDFLAGS_vmlinux in arch/arm/boot/compressed/Makefile is for
arch/arm/boot/compressed/vmlinux. They just happen to have the same
variable name, but are used for different purposes. Stop shadowing
LDFLAGS_vmlinux.
This commit passes LDFLAGS_vmlinux to scripts/link-vmlinux.sh via a
command line parameter instead of via an environment variable. LD and
KBUILD_LDFLAGS are exported, but I did the same for consistency. Anyway,
they must be included in cmd_link-vmlinux to allow if_changed to detect
the changes in LD or KBUILD_LDFLAGS.
The following Makefiles are not affected:
arch/arm/boot/compressed/Makefile
arch/h8300/boot/compressed/Makefile
arch/nios2/boot/compressed/Makefile
arch/parisc/boot/compressed/Makefile
arch/s390/boot/compressed/Makefile
arch/sh/boot/compressed/Makefile
arch/sh/boot/romimage/Makefile
arch/x86/boot/compressed/Makefile
They use ':=' or '=' to clear the LDFLAGS_vmlinux inherited from the
top Makefile.
We need to take a closer look at the impact to unicore32 and xtensa.
arch/unicore32/boot/compressed/Makefile only uses '+=' operator for
LDFLAGS_vmlinux. So, the decompressor previously inherited the linker
flags from the top Makefile.
However, commit 70fac51fea ("unicore32 additional architecture files:
boot process") was merged before commit 1f2bfbd00e ("kbuild: link of
vmlinux moved to a script"). So, I rather consider this is a bug fix of
1f2bfbd00e.
arch/xtensa/boot/boot-elf/Makefile is also affected, but this is also
considered a fix for the same reason. It did not inherit LDFLAGS_vmlinux
when commit 4bedea9454 ("[PATCH] xtensa: Architecture support for
Tensilica Xtensa Part 2") was merged. I deleted $(LDFLAGS_vmlinux),
which is now empty.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Using BTF_ID_LIST macro to define lists for several helpers
using BTF arguments.
And running resolve_btfids on vmlinux elf object during linking,
so the .BTF_ids section gets the IDs resolved.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-5-jolsa@kernel.org
Alexei Starovoitov says:
====================
pull-request: bpf 2020-06-12
The following pull-request contains BPF updates for your *net* tree.
We've added 26 non-merge commits during the last 10 day(s) which contain
a total of 27 files changed, 348 insertions(+), 93 deletions(-).
The main changes are:
1) sock_hash accounting fix, from Andrey.
2) libbpf fix and probe_mem sanitizing, from Andrii.
3) sock_hash fixes, from Jakub.
4) devmap_val fix, from Jesper.
5) load_bytes_relative fix, from YiFei.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
bpf_iter requires the kernel BTF to be generated with
pahole >= 1.16, since otherwise the function definitions
that the iterator attaches to are not included.
This failure mode is indistiguishable from trying to attach
to an iterator that really doesn't exist.
Since it's really easy to miss this requirement, bump the
pahole version check used at build time to at least 1.16.
Fixes: 15d83c4d7c ("bpf: Allow loading of a bpf_iter program")
Suggested-by: Ivan Babrou <ivan@cloudflare.com>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200608094257.47366-1-lmb@cloudflare.com
- fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32
- ensure to rebuild all objects when the compiler is upgraded
- exclude system headers from dependency tracking and fixdep processing
- fix potential bit-size mismatch between the kernel and BPF user-mode
helper
- add the new syntax 'userprogs' to build user-space programs for the
target architecture (the same arch as the kernel)
- compile user-space sample code under samples/ for the target arch
instead of the host arch
- make headers_install fail if a CONFIG option is leaked to user-space
- sanitize the output format of scripts/checkstack.pl
- handle ARM 'push' instruction in scripts/checkstack.pl
- error out before modpost if a module name conflict is found
- error out when multiple directories are passed to M= because this
feature is broken for a long time
- add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info
- a lot of cleanups of modpost
- dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
second pass of modpost
- do not run the second pass of modpost if nothing in modules is updated
- install modules.builtin(.modinfo) by 'make install' as well as by
'make modules_install' because it is useful even when CONFIG_MODULES=n
- add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
to allow users to use alternatives such as pigz, pbzip2, etc.
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Merge tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32
- ensure to rebuild all objects when the compiler is upgraded
- exclude system headers from dependency tracking and fixdep processing
- fix potential bit-size mismatch between the kernel and BPF user-mode
helper
- add the new syntax 'userprogs' to build user-space programs for the
target architecture (the same arch as the kernel)
- compile user-space sample code under samples/ for the target arch
instead of the host arch
- make headers_install fail if a CONFIG option is leaked to user-space
- sanitize the output format of scripts/checkstack.pl
- handle ARM 'push' instruction in scripts/checkstack.pl
- error out before modpost if a module name conflict is found
- error out when multiple directories are passed to M= because this
feature is broken for a long time
- add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info
- a lot of cleanups of modpost
- dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
second pass of modpost
- do not run the second pass of modpost if nothing in modules is
updated
- install modules.builtin(.modinfo) by 'make install' as well as by
'make modules_install' because it is useful even when
CONFIG_MODULES=n
- add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
to allow users to use alternatives such as pigz, pbzip2, etc.
* tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits)
kbuild: add variables for compression tools
Makefile: install modules.builtin even if CONFIG_MODULES=n
mksysmap: Fix the mismatch of '.L' symbols in System.map
kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS
modpost: change elf_info->size to size_t
modpost: remove is_vmlinux() helper
modpost: strip .o from modname before calling new_module()
modpost: set have_vmlinux in new_module()
modpost: remove mod->skip struct member
modpost: add mod->is_vmlinux struct member
modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()
modpost: remove mod->is_dot_o struct member
modpost: move -d option in scripts/Makefile.modpost
modpost: remove -s option
modpost: remove get_next_text() and make {grab,release_}file static
modpost: use read_text_file() and get_line() for reading text files
modpost: avoid false-positive file open error
modpost: fix potential mmap'ed file overrun in get_src_version()
modpost: add read_text_file() and get_line() helpers
modpost: do not call get_modinfo() for vmlinux(.o)
...
The full build runs modpost twice, first for vmlinux.o and second for
modules.
The first pass dumps all the vmlinux symbols into Module.symvers, but
the second pass parses vmlinux again instead of reusing the dump file,
presumably because it needs to avoid accumulating stale symbols.
Loading symbol info from a dump file is faster than parsing an ELF object.
Besides, modpost deals with various issues to parse vmlinux in the second
pass.
A solution is to make the first pass dumps symbols into a separate file,
vmlinux.symvers. The second pass reads it, and parses module .o files.
The merged symbol information is dumped into Module.symvers in the same
way as before.
This makes further modpost cleanups possible.
Also, it fixes the problem of 'make vmlinux', which previously overwrote
Module.symvers, throwing away module symbols.
I slightly touched scripts/link-vmlinux.sh so that vmlinux is re-linked
when you cross this commit. Otherwise, vmlinux.symvers would not be
generated.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Now that objtool is capable of processing vmlinux.o and actually has
something useful to do there, (conditionally) add it to the final link
pass.
This will increase build time by a few seconds.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200416115119.287494491@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Simplify gen_btf logic to make it work with llvm-objcopy. The existing
'file format' and 'architecture' parsing logic is brittle and does not
work with llvm-objcopy/llvm-objdump.
'file format' output of llvm-objdump>=11 will match GNU objdump, but
'architecture' (bfdarch) may not.
.BTF in .tmp_vmlinux.btf is non-SHF_ALLOC. Add the SHF_ALLOC flag
because it is part of vmlinux image used for introspection. C code
can reference the section via linker script defined __start_BTF and
__stop_BTF. This fixes a small problem that previous .BTF had the
SHF_WRITE flag (objcopy -I binary -O elf* synthesized .data).
Additionally, `objcopy -I binary` synthesized symbols
_binary__btf_vmlinux_bin_start and _binary__btf_vmlinux_bin_stop (not
used elsewhere) are replaced with more commonplace __start_BTF and
__stop_BTF.
Add 2>/dev/null because GNU objcopy (but not llvm-objcopy) warns
"empty loadable segment detected at vaddr=0xffffffff81000000, is this intentional?"
We use a dd command to change the e_type field in the ELF header from
ET_EXEC to ET_REL so that lld will accept .btf.vmlinux.bin.o. Accepting
ET_EXEC as an input file is an extremely rare GNU ld feature that lld
does not intend to support, because this is error-prone.
The output section description .BTF in include/asm-generic/vmlinux.lds.h
avoids potential subtle orphan section placement issues and suppresses
--orphan-handling=warn warnings.
Fixes: df786c9b94 ("bpf: Force .BTF section start to zero when dumping from vmlinux")
Fixes: cb0cc635c7 ("powerpc: Include .BTF section")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Stanislav Fomichev <sdf@google.com>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://github.com/ClangBuiltLinux/linux/issues/871
Link: https://lore.kernel.org/bpf/20200318222746.173648-1-maskray@google.com
When CONFIG_DEBUG_INFO is enabled, the two kallsyms linking steps spend
time collecting and writing the dwarf sections to the temporary output
files. kallsyms does not need this information, and leaving it off
halves their linking time. This is especially noticeable without
CONFIG_DEBUG_INFO_REDUCED. The BTF linking stage, however, does still
need those details.
Refactor the BTF and kallsyms generation stages slightly for more
regularized temporary names. Skip debug during kallsyms links.
Additionally move "info BTF" to the correct place since commit
8959e39272 ("kbuild: Parameterize kallsyms generation and correct
reporting"), which added "info LD ..." to vmlinux_link calls.
For a full debug info build with BTF, my link time goes from 1m06s to
0m54s, saving about 12 seconds, or 18%.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/202003031814.4AEA3351@keescook
Since commit 56d5893615 ("kbuild: do not create orphan built-in.a or
obj-y objects"), scripts/link-vmlinux.sh does nothing when descending
into init/.
Once the version number becomes out of sync between .version and
include/generated/compile.h, it is not self-healing.
[How to reproduce]
$ echo 100 > .version
$ make
You will see the number in the .version is always bigger than that in
compile.h by one. After this, every time you run 'make', the vmlinux is
re-linked even when none of source files is updated.
Fixes: 56d5893615 ("kbuild: do not create orphan built-in.a or obj-y objects")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
- detect missing include guard in UAPI headers
- do not create orphan built-in.a or obj-y objects
- generate modules.builtin more simply, and drop tristate.conf
- simplify built-in initramfs creation
- make linux-headers deb package thinner
- optimize the deb package build script
- misc cleanups
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Merge tag 'kbuild-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- detect missing include guard in UAPI headers
- do not create orphan built-in.a or obj-y objects
- generate modules.builtin more simply, and drop tristate.conf
- simplify built-in initramfs creation
- make linux-headers deb package thinner
- optimize the deb package build script
- misc cleanups
* tag 'kbuild-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
builddeb: split libc headers deployment out into a function
builddeb: split kernel headers deployment out into a function
builddeb: remove redundant make for ARCH=um
builddeb: avoid invoking sub-shells where possible
builddeb: remove redundant $objtree/
builddeb: match temporary directory name to the package name
builddeb: remove unneeded files in hdrobjfiles for headers package
kbuild: use -S instead of -E for precise cc-option test in Kconfig
builddeb: allow selection of .deb compressor
kbuild: remove 'Building modules, stage 2.' log
kbuild: remove *.tmp file when filechk fails
kbuild: remove PYTHON2 variable
modpost: assume STT_SPARC_REGISTER is defined
gen_initramfs.sh: remove intermediate cpio_list on errors
initramfs: refactor the initramfs build rules
gen_initramfs.sh: always output cpio even without -o option
initramfs: add default_cpio_list, and delete -d option support
initramfs: generate dependency list and cpio at the same time
initramfs: specify $(src)/gen_initramfs.sh as a prerequisite in Makefile
initramfs: make initramfs compression choice non-optional
...
Pull networking updates from David Miller:
1) Add WireGuard
2) Add HE and TWT support to ath11k driver, from John Crispin.
3) Add ESP in TCP encapsulation support, from Sabrina Dubroca.
4) Add variable window congestion control to TIPC, from Jon Maloy.
5) Add BCM84881 PHY driver, from Russell King.
6) Start adding netlink support for ethtool operations, from Michal
Kubecek.
7) Add XDP drop and TX action support to ena driver, from Sameeh
Jubran.
8) Add new ipv4 route notifications so that mlxsw driver does not have
to handle identical routes itself. From Ido Schimmel.
9) Add BPF dynamic program extensions, from Alexei Starovoitov.
10) Support RX and TX timestamping in igc, from Vinicius Costa Gomes.
11) Add support for macsec HW offloading, from Antoine Tenart.
12) Add initial support for MPTCP protocol, from Christoph Paasch,
Matthieu Baerts, Florian Westphal, Peter Krystad, and many others.
13) Add Octeontx2 PF support, from Sunil Goutham, Geetha sowjanya, Linu
Cherian, and others.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1469 commits)
net: phy: add default ARCH_BCM_IPROC for MDIO_BCM_IPROC
udp: segment looped gso packets correctly
netem: change mailing list
qed: FW 8.42.2.0 debug features
qed: rt init valid initialization changed
qed: Debug feature: ilt and mdump
qed: FW 8.42.2.0 Add fw overlay feature
qed: FW 8.42.2.0 HSI changes
qed: FW 8.42.2.0 iscsi/fcoe changes
qed: Add abstraction for different hsi values per chip
qed: FW 8.42.2.0 Additional ll2 type
qed: Use dmae to write to widebus registers in fw_funcs
qed: FW 8.42.2.0 Parser offsets modified
qed: FW 8.42.2.0 Queue Manager changes
qed: FW 8.42.2.0 Expose new registers and change windows
qed: FW 8.42.2.0 Internal ram offsets modifications
MAINTAINERS: Add entry for Marvell OcteonTX2 Physical Function driver
Documentation: net: octeontx2: Add RVU HW and drivers overview
octeontx2-pf: ethtool RSS config support
octeontx2-pf: Add basic ethtool support
...
When trying to compile with CONFIG_DEBUG_INFO_BTF enabled, I got this
error:
% make -s
Failed to generate BTF for vmlinux
Try to disable CONFIG_DEBUG_INFO_BTF
make[3]: *** [vmlinux] Error 1
Compiling again without -s shows the true error (that pahole is
missing), but since this is fatal, we should show the error
unconditionally on stderr as well, not silence it using the `info`
function. With this patch:
% make -s
BTF: .tmp_vmlinux.btf: pahole (pahole) is not available
Failed to generate BTF for vmlinux
Try to disable CONFIG_DEBUG_INFO_BTF
make[3]: *** [vmlinux] Error 1
Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200122000110.GA310073@chrisdown.name
Commit bc081dd6e9 ("kbuild: generate modules.builtin") added
infrastructure to generate modules.builtin, the list of all
builtin modules.
Basically, it works like this:
- Kconfig generates include/config/tristate.conf, the list of
tristate CONFIG options with a value in a capital letter.
- scripts/Makefile.modbuiltin makes Kbuild descend into
directories to collect the information of builtin modules.
I am not a big fan of it because Kbuild ends up with traversing
the source tree twice.
I am not sure how perfectly it should work, but this approach cannot
avoid false positives; even if the relevant CONFIG option is tristate,
some Makefiles forces obj-m to obj-y.
Some examples are:
arch/powerpc/platforms/powermac/Makefile:
obj-$(CONFIG_NVRAM:m=y) += nvram.o
net/ipv6/Makefile:
obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
net/netlabel/Makefile:
obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o
Nobody has complained about (or noticed) it, so it is probably fine to
have false positives in modules.builtin.
This commit simplifies the implementation. Let's exploit the fact
that every module has MODULE_LICENSE(). (modpost shows a warning if
MODULE_LICENSE is missing. If so, 0-day bot would already have blocked
such a module.)
I added MODULE_FILE to <linux/module.h>. When the code is being compiled
as builtin, it will be filled with the file path of the module, and
collected into modules.builtin.info. Then, scripts/link-vmlinux.sh
extracts the list of builtin modules out of it.
This new approach fixes the false-positives above, but adds another
type of false-positives; non-modular code may have MODULE_LICENSE()
by mistake. This is not a big deal, it is just the code is always
orphan. We can clean it up if we like. You can see cleanup examples by:
$ git log --grep='make.* explicitly non-modular'
To sum up, this commits deletes lots of code, but still produces almost
equivalent results. Please note it does not increase the vmlinux size at
all. As you can see in include/asm-generic/vmlinux.lds.h, the .modinfo
section is discarded in the link stage.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Now that the orc_unwind and orc_unwind_ip tables are sorted at build time,
remove the boot time sorting pass.
No change in functionality.
[ mingo: Rewrote the changelog and code comments. ]
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-8-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
