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2022-10-03kbuild: rebuild .vmlinux.export.o when its prerequisite is updatedMasahiro Yamada1-5/+0
When include/linux/export-internal.h is updated, .vmlinux.export.o must be rebuilt, but it does not happen because its rule is hidden behind scripts/link-vmlinux.sh. Move it out of the shell script, so that Make can see the dependency between vmlinux and .vmlinux.export.o. Move the vmlinux rule to scripts/Makefile.vmlinux. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-10-03kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_oMasahiro Yamada1-7/+0
Do not build modules.builtin(.modinfo) as a side-effect of vmlinux. There are no good reason to rebuild them just because any of vmlinux's prerequistes (vmlinux.lds, .vmlinux.export.c, etc.) has been updated. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-10-02kallsyms: take the input file instead of reading stdinMasahiro Yamada1-1/+1
This gets rid of the pipe operator connected with 'cat'. Also use getopt_long() to parse the command line. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-10-02kbuild: reuse mksysmap output for kallsymsMasahiro Yamada1-6/+5
scripts/mksysmap internally runs ${NM} (dropping some symbols). When CONFIG_KALLSYMS=y, mksysmap creates .tmp_System.map, but it is almost the same as the output from the ${NM} invocation in kallsyms(). It is true scripts/mksysmap drops some symbols, but scripts/kallsyms.c ignores more anyway. Keep the mksysmap output as *.syms, and reuse it for kallsyms and 'cmp -s'. It saves one ${NM} invocation. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-10-02kbuild: use obj-y instead extra-y for objects placed at the headMasahiro Yamada1-6/+4
The objects placed at the head of vmlinux need special treatments: - arch/$(SRCARCH)/Makefile adds them to head-y in order to place them before other archives in the linker command line. - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of obj-y to avoid them going into built-in.a. This commit gets rid of the latter. Create vmlinux.a to collect all the objects that are unconditionally linked to vmlinux. The objects listed in head-y are moved to the head of vmlinux.a by using 'ar m'. With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y for builtin objects. There is no *.o that is directly linked to vmlinux. Drop unneeded code in scripts/clang-tools/gen_compile_commands.py. $(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested by Nathan Chancellor [1]. [1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-09-29kbuild: unify two modpost invocationsMasahiro Yamada1-3/+0
Currently, modpost is executed twice; first for vmlinux, second for modules. This commit merges them. Current build flow ================== 1) build obj-y and obj-m objects 2) link vmlinux.o 3) modpost for vmlinux 4) link vmlinux 5) modpost for modules 6) link modules (*.ko) The build steps 1) through 6) are serialized, that is, modules are built after vmlinux. You do not get benefits of parallel builds when scripts/link-vmlinux.sh is being run. New build flow ============== 1) build obj-y and obj-m objects 2) link vmlinux.o 3) modpost for vmlinux and modules 4a) link vmlinux 4b) link modules (*.ko) In the new build flow, modpost is invoked just once. vmlinux and modules are built in parallel. One exception is CONFIG_DEBUG_INFO_BTF_MODULES=y, where modules depend on vmlinux. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-09-29kbuild: move vmlinux.o rule to the top MakefileMasahiro Yamada1-3/+0
Move the build rules of vmlinux.o out of scripts/link-vmlinux.sh to clearly separate 1) pre-modpost, 2) modpost, 3) post-modpost stages. This will make further refactoring possible. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-09-29kbuild: move .vmlinux.objs rule to Makefile.modpostMasahiro Yamada1-18/+0
.vmlinux.objs is used by modpost, so scripts/Makefile.modpost is a better place to generate it. It is used only when CONFIG_MODVERSIONS=y. It should be guarded by "ifdef CONFIG_MODVERSIONS". Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-09-29kbuild: build init/built-in.a just onceMasahiro Yamada1-13/+4
Kbuild builds init/built-in.a twice; first during the ordinary directory descending, second from scripts/link-vmlinux.sh. We do this because UTS_VERSION contains the build version and the timestamp. We cannot update it during the normal directory traversal since we do not yet know if we need to update vmlinux. UTS_VERSION is temporarily calculated, but omitted from the update check. Otherwise, vmlinux would be rebuilt every time. When Kbuild results in running link-vmlinux.sh, it increments the version number in the .version file and takes the timestamp at that time to really fix UTS_VERSION. However, updating the same file twice is a footgun. To avoid nasty timestamp issues, all build artifacts that depend on init/built-in.a are atomically generated in link-vmlinux.sh, where some of them do not need rebuilding. To fix this issue, this commit changes as follows: [1] Split UTS_VERSION out to include/generated/utsversion.h from include/generated/compile.h include/generated/utsversion.h is generated just before the vmlinux link. It is generated under include/generated/ because some decompressors (s390, x86) use UTS_VERSION. [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c from init/version.c init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary directory descending, they are compiled with __weak and used to determine if vmlinux needs relinking. Just before the vmlinux link, they are compiled without __weak to embed the real version and timestamp. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-06-05kbuild: factor out the common objtool argumentsMasahiro Yamada1-71/+0
scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups for the objtool arguments. It was difficult to factor out them because all the vmlinux build rules were written in a shell script. It is somewhat tedious to touch the two files every time a new objtool option is supported. To reduce the code duplication, move the objtool for vmlinux.o into scripts/Makefile.vmlinux_o. Then, move the common macros to Makefile.lib so they are shared between Makefile.build and Makefile.vmlinux_o. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-06-05kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_oMasahiro Yamada1-40/+1
This is a preparation for moving the objtool rule in the next commit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-06-05kbuild: clean .tmp_* pattern by make cleanMasahiro Yamada1-3/+0
Change the "make clean" rule to remove all the .tmp_* files. .tmp_objdiff is the only exception, which should be removed by "make mrproper". Rename the record directory of objdiff, .tmp_objdiff to .objdiff to avoid the removal by "make clean". Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-06-01kbuild: remove redundant cleanups in scripts/link-vmlinux.shMasahiro Yamada1-2/+0
These are cleaned by the top Makefile. vmlinux.o and .vmlinux.d matches the '*.[aios]' and '.*.d' patterns respectively. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-29kbuild: do not try to parse *.cmd files for objects provided by compilerMasahiro Yamada1-1/+8
Guenter Roeck reported the build breakage for parisc and csky. I confirmed nios2 and openrisc are broken as well. The reason is that they borrow libgcc.a from the toolchains. For example, see this line in arch/parisc/Makefile: LIBGCC := $(shell $(CC) -print-libgcc-file-name) Some objects in libgcc.a are linked to vmlinux.o, but they do not have .*.cmd files. Obviously, there is no EXPORT_SYMBOL in external objects. Ignore them. (Most of the architectures import library code into the kernel tree. Perhaps those 4 architectures can do similar, but I do not know how challenging it is.) Fixes: f292d875d0dc ("modpost: extract symbol versions from *.cmd files") Link: https://lore.kernel.org/linux-kbuild/20220528224745.GA2501857@roeck-us.net/T/#mac65c20c71c3e272db0350ecfba53fcd8905b0a0 Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Guenter Roeck <linux@roeck-us.net>
2022-05-26Merge tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuildLinus Torvalds1-20/+20
Pull Kbuild updates from Masahiro Yamada: - Add HOSTPKG_CONFIG env variable to allow users to override pkg-config - Support W=e as a shorthand for KCFLAGS=-Werror - Fix CONFIG_IKHEADERS build to support toybox cpio - Add scripts/dummy-tools/pahole to ease distro packagers' life - Suppress false-positive warnings from checksyscalls.sh for W=2 build - Factor out the common code of arch/*/boot/install.sh into scripts/install.sh - Support 'kernel-install' tool in scripts/prune-kernel - Refactor module-versioning to link the symbol versions at the final link of vmlinux and modules - Remove CONFIG_MODULE_REL_CRCS because module-versioning now works in an arch-agnostic way - Refactor modpost, Makefiles * tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (56 commits) genksyms: adjust the output format to modpost kbuild: stop merging *.symversions kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS modpost: extract symbol versions from *.cmd files modpost: add sym_find_with_module() helper modpost: change the license of EXPORT_SYMBOL to bool type modpost: remove left-over cross_compile declaration kbuild: record symbol versions in *.cmd files kbuild: generate a list of objects in vmlinux modpost: move *.mod.c generation to write_mod_c_files() modpost: merge add_{intree_flag,retpoline,staging_flag} to add_header scripts/prune-kernel: Use kernel-install if available kbuild: factor out the common installation code into scripts/install.sh modpost: split new_symbol() to symbol allocation and hash table addition modpost: make sym_add_exported() always allocate a new symbol modpost: make multiple export error modpost: dump Module.symvers in the same order of modules.order modpost: traverse the namespace_list in order modpost: use doubly linked list for dump_lists modpost: traverse unresolved symbols in order ...
2022-05-24Merge tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-23/+39
Pull objtool updates from Ingo Molnar: - Comprehensive interface overhaul: ================================= Objtool's interface has some issues: - Several features are done unconditionally, without any way to turn them off. Some of them might be surprising. This makes objtool tricky to use, and prevents porting individual features to other arches. - The config dependencies are too coarse-grained. Objtool enablement is tied to CONFIG_STACK_VALIDATION, but it has several other features independent of that. - The objtool subcmds ("check" and "orc") are clumsy: "check" is really a subset of "orc", so it has all the same options. The subcmd model has never really worked for objtool, as it only has a single purpose: "do some combination of things on an object file". - The '--lto' and '--vmlinux' options are nonsensical and have surprising behavior. Overhaul the interface: - get rid of subcmds - make all features individually selectable - remove and/or clarify confusing/obsolete options - update the documentation - fix some bugs found along the way - Fix x32 regression - Fix Kbuild cleanup bugs - Add scripts/objdump-func helper script to disassemble a single function from an object file. - Rewrite scripts/faddr2line to be section-aware, by basing it on 'readelf', moving it away from 'nm', which doesn't handle multiple sections well, which can result in decoding failure. - Rewrite & fix symbol handling - which had a number of bugs wrt. object files that don't have global symbols - which is rare but possible. Also fix a bunch of symbol handling bugs found along the way. * tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) objtool: Fix objtool regression on x32 systems objtool: Fix symbol creation scripts/faddr2line: Fix overlapping text section failures scripts: Create objdump-func helper script objtool: Remove libsubcmd.a when make clean objtool: Remove inat-tables.c when make clean objtool: Update documentation objtool: Remove --lto and --vmlinux in favor of --link objtool: Add HAVE_NOINSTR_VALIDATION objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION" objtool: Make noinstr hacks optional objtool: Make jump label hack optional objtool: Make static call annotation optional objtool: Make stack validation frame-pointer-specific objtool: Add CONFIG_OBJTOOL objtool: Extricate sls from stack validation objtool: Rework ibt and extricate from stack validation objtool: Make stack validation optional objtool: Add option to print section addresses objtool: Don't print parentheses in function addresses ...
2022-05-24kbuild: stop merging *.symversionsMasahiro Yamada1-19/+0
Now modpost reads symbol versions from .*.cmd files. The merged *.symversions are no longer needed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-24kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCSMasahiro Yamada1-1/+9
include/{linux,asm-generic}/export.h defines a weak symbol, __crc_* as a placeholder. Genksyms writes the version CRCs into the linker script, which will be used for filling the __crc_* symbols. The linker script format depends on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset to the reference of CRC. It is time to get rid of this complexity. Now that modpost parses text files (.*.cmd) to collect all the CRCs, it can generate C code that will be linked to the vmlinux or modules. Generate a new C file, .vmlinux.export.c, which contains the CRCs of symbols exported by vmlinux. It is compiled and linked to vmlinux in scripts/link-vmlinux.sh. Put the CRCs of symbols exported by modules into the existing *.mod.c files. No additional build step is needed for modules. As before, *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal. No linker magic is used here. The new C implementation works in the same way, whether CONFIG_RELOCATABLE is enabled or not. CONFIG_MODULE_REL_CRCS is no longer needed. Previously, Kbuild invoked additional $(LD) to update the CRCs in objects, but this step is unneeded too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-05-23Merge tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-3/+3
Pull x86 CPU feature updates from Borislav Petkov: - Remove a bunch of chicken bit options to turn off CPU features which are not really needed anymore - Misc fixes and cleanups * tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/speculation: Add missing prototype for unpriv_ebpf_notify() x86/pm: Fix false positive kmemleak report in msr_build_context() x86/speculation/srbds: Do not try to turn mitigation off when not supported x86/cpu: Remove "noclflush" x86/cpu: Remove "noexec" x86/cpu: Remove "nosmep" x86/cpu: Remove CONFIG_X86_SMAP and "nosmap" x86/cpu: Remove "nosep" x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid=
2022-05-11kbuild: generate a list of objects in vmlinuxMasahiro Yamada1-0/+11
A *.mod file lists the member objects of a module, but vmlinux does not have such a file. Generate this list to allow modpost to know all the member objects. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2022-04-22objtool: Remove --lto and --vmlinux in favor of --linkJosh Poimboeuf1-5/+3
The '--lto' option is a confusing way of telling objtool to do stack validation despite it being a linked object. It's no longer needed now that an explicit '--stackval' option exists. The '--vmlinux' option is also redundant. Remove both options in favor of a straightforward '--link' option which identifies a linked object. Also, implicitly set '--link' with a warning if the user forgets to do so and we can tell that it's a linked object. This makes it easier for manual vmlinux runs. 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/dcd3ceffd15a54822c6183e5766d21ad06082b45.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION"Josh Poimboeuf1-1/+1
CONFIG_VMLINUX_VALIDATION is just the validation of the "noinstr" rules. That name is a misnomer, because now objtool actually does vmlinux validation for other reasons. Rename CONFIG_VMLINUX_VALIDATION to CONFIG_NOINSTR_VALIDATION. 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/173f07e2d6d1afc0874aed975a61783207c6a531.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Make noinstr hacks optionalJosh Poimboeuf1-0/+4
Objtool has some hacks in place to workaround toolchain limitations which otherwise would break no-instrumentation rules. Make the hacks explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. 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/b326eeb9c33231b9dfbb925f194ed7ee40edcd7c.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Make jump label hack optionalJosh Poimboeuf1-0/+4
Objtool secretly does a jump label hack to overcome the limitations of the toolchain. Make the hack explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. 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/3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Make static call annotation optionalJosh Poimboeuf1-1/+4
As part of making objtool more modular, put the existing static call code behind a new '--static-call' option. 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/d59ac57ef3d6d8380cdce20322314c9e2e556750.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Make stack validation frame-pointer-specificJosh Poimboeuf1-4/+0
Now that CONFIG_STACK_VALIDATION is frame-pointer specific, do the same for the '--stackval' option. Now the '--no-fp' option is redundant and can be removed. 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/f563fa064b3b63d528de250c72012d49e14742a3.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Add CONFIG_OBJTOOLJosh Poimboeuf1-14/+18
Now that stack validation is an optional feature of objtool, add CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with it. CONFIG_STACK_VALIDATION can now be considered to be frame-pointer specific. CONFIG_UNWINDER_ORC is already inherently valid for live patching, so no need to "validate" it. 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/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Make stack validation optionalJosh Poimboeuf1-0/+4
Make stack validation an explicit cmdline option so that individual objtool features can be enabled individually by other arches. 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/52da143699574d756e65ca4c9d4acaffe9b0fe5f.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Ditch subcommandsJosh Poimboeuf1-8/+5
Objtool has a fairly singular focus. It runs on object files and does validations and transformations which can be combined in various ways. The subcommand model has never been a good fit, making it awkward to combine and remove options. Remove the "check" and "orc" subcommands in favor of a more traditional cmdline option model. This makes it much more flexible to use, and easier to port individual features to other arches. 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/5c61ebf805e90aefc5fa62bc63468ffae53b9df6.1650300597.git.jpoimboe@redhat.com
2022-04-22objtool: Reorganize cmdline optionsJosh Poimboeuf1-11/+19
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
2022-04-19objtool: Enable unreachable warnings for CLANG LTOJosh Poimboeuf1-1/+1
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: ed53a0d97192 ("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
2022-04-04x86/cpu: Remove CONFIG_X86_SMAP and "nosmap"Borislav Petkov1-3/+3
Those were added as part of the SMAP enablement but SMAP is currently an integral part of kernel proper and there's no need to disable it anymore. Rip out that functionality. Leave --uaccess default on for objtool as this is what objtool should do by default anyway. If still needed - clearcpuid=smap. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220127115626.14179-4-bp@alien8.de
2022-04-02kbuild: fix empty ${PYTHON} in scripts/link-vmlinux.shMasahiro Yamada1-1/+1
The two commits d8d2d38275c1 ("kbuild: remove PYTHON variable") a8cccdd95473 ("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>
2022-03-15x86/alternative: Use .ibt_endbr_seal to seal indirect callsPeter Zijlstra1-2/+8
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
2022-03-15objtool: Rename --duplicate to --ltoPeter Zijlstra1-1/+1
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
2022-01-19Merge tag 'kbuild-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuildLinus Torvalds1-24/+25
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 ...
2022-01-16Merge tag 'trace-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-traceLinus Torvalds1-3/+3
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() ...
2022-01-13scripts: ftrace - move the sort-processing in ftrace_initYinan Liu1-3/+3
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>
2022-01-08kbuild: do not include include/config/auto.conf from shell scriptsMasahiro Yamada1-23/+24
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>
2021-12-09x86: Add straight-line-speculation mitigationPeter Zijlstra1-0/+3
Make use of an upcoming GCC feature to mitigate straight-line-speculation for x86: https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952 https://bugs.llvm.org/show_bug.cgi?id=52323 It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11. Maintenance overhead of this should be fairly low due to objtool validation. Size overhead of all these additional int3 instructions comes to: text data bss dec hex filename 22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux 22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls Or roughly 2.4% additional text. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211204134908.140103474@infradead.org
2021-11-08Merge tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuildLinus Torvalds1-3/+3
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 ...
2021-11-01kbuild: Unify options for BTF generation for vmlinux and modulesJiri Olsa1-10/+1
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
2021-10-12scripts: update the comments of kallsyms supportHui Su1-3/+3
update the comments of kallsyms support. Fixes: af73d78bd384 ("kbuild: Remove debug info from kallsyms linking") Signed-off-by: Hui Su <suhui_kernel@163.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-03kbuild: merge vmlinux_link() between ARCH=um and other architecturesMasahiro Yamada1-33/+23
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>
2021-09-03kbuild: do not remove 'linux' link in scripts/link-vmlinux.shMasahiro Yamada1-1/+0
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>
2021-09-03kbuild: merge vmlinux_link() between the ordinary link and Clang LTOMasahiro Yamada1-16/+14
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>
2021-07-10Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuildLinus Torvalds1-3/+1
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 ...
2021-06-29kbuild: skip per-CPU BTF generation for pahole v1.18-v1.21Andrii Nakryiko1-0/+4
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>
2021-05-27kbuild: Quote OBJCOPY var to avoid a pahole call break the buildJavier Martinez Canillas1-1/+1
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: 5f9ae91f7c0d ("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
2021-05-27kbuild: clean up ${quiet} checks in shell scriptsMasahiro Yamada1-3/+1
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>
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