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2019-07-17kbuild: do not create empty modules.order in the prepare stageMasahiro Yamada
Currently, $(objtree)/modules.order is touched in two places. In the 'prepare0' rule, scripts/Makefile.build creates an empty modules.order while processing 'obj=.' In the 'modules' rule, the top-level Makefile overwrites it with the correct list of modules. While this might be a good side-effect that modules.order is made empty every time (probably this is not intended functionality), I personally do not like this behavior. Create modules.order only when it is sensible to do so. This avoids creating the following pointless files: scripts/basic/modules.order scripts/dtc/modules.order scripts/gcc-plugins/modules.order scripts/genksyms/modules.order scripts/mod/modules.order scripts/modules.order scripts/selinux/genheaders/modules.order scripts/selinux/mdp/modules.order scripts/selinux/modules.order Going forward, $(objtree)/modules.order lists the modules that was built in the last successful build. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-17kbuild: compile-test headers listed in header-test-m as wellMasahiro Yamada
It will be useful to control the header-test by a tristate option. If CONFIG_FOO is a tristate option, you can write like this: header-test-$(CONFIG_FOO) += foo.h Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-11kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctreeMasahiro Yamada
Commit 25b146c5b8ce ("kbuild: allow Kbuild to start from any directory") deprecated KBUILD_SRCTREE. It is only used in tools/testing/selftest/ to distinguish out-of-tree build. Replace it with a new boolean flag, building_out_of_srctree. I also replaced the conditional ($(srctree),.) because the next commit will allow an absolute path to be used for $(srctree) even when building in the source tree. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-09kbuild: do not create wrappers for header-test-yMasahiro Yamada
header-test-y does not work with headers in sub-directories. For example, you may want to write a Makefile, like this: include/linux/Kbuild: header-test-y += mtd/nand.h This entry will create a wrapper include/linux/mtd/nand.hdrtest.c with the following content: #include "mtd/nand.h" To make this work, we need to add $(srctree)/include/linux to the header search path. It would be tedious to add ccflags-y. Instead, we could change the *.hdrtest.c rule to wrap: #include "nand.h" This works for in-tree build since #include "..." searches in the relative path from the header with this directive. For O=... build, we need to add $(srctree)/include/linux/mtd to the header search path, which will be even more tedious. After all, I thought it would be handier to compile headers directly without creating wrappers. I added a new build rule to compile %.h into %.h.s The target is %.h.s instead of %.h.o because it is slightly faster. Also, as for GCC, an empty assembly is smaller than an empty object. I wrote the build rule: $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $< instead of: $(CC) $(c_flags) -S -o $@ -x c $< Both work fine with GCC, but the latter is bad for Clang. This comes down to the difference in the -Wunused-function policy. GCC does not warn about unused 'static inline' functions at all. Clang does not warn about the ones in included headers, but does about the ones in the source. So, we should handle headers as headers, not as source files. In fact, this has been hidden since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"), but we should not rely on that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Tested-by: Jani Nikula <jani.nikula@intel.com>
2019-06-15kbuild: add support for ensuring headers are self-containedJani Nikula
Sometimes it's useful to be able to explicitly ensure certain headers remain self-contained, i.e. that they are compilable as standalone units, by including and/or forward declaring everything they depend on. Add special target header-test-y where individual Makefiles can add headers to be tested if CONFIG_HEADER_TEST is enabled. This will generate a dummy C file per header that gets built as part of extra-y. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-08Merge tag 'kbuild-v5.2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - allow users to invoke 'make' out of the source tree - refactor scripts/mkmakefile - deprecate KBUILD_SRC, which was used to track the source tree location for O= build. - fix recordmcount.pl in case objdump output is localized - turn unresolved symbols in external modules to errors from warnings by default; pass KBUILD_MODPOST_WARN=1 to get them back to warnings - generate modules.builtin.modinfo to collect .modinfo data from built-in modules - misc Makefile cleanups * tag 'kbuild-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits) .gitignore: add more all*.config patterns moduleparam: Save information about built-in modules in separate file Remove MODULE_ALIAS() calls that take undefined macro .gitignore: add leading and trailing slashes to generated directories scripts/tags.sh: fix direct execution of scripts/tags.sh scripts: override locale from environment when running recordmcount.pl samples: kobject: allow CONFIG_SAMPLE_KOBJECT to become y samples: seccomp: turn CONFIG_SAMPLE_SECCOMP into a bool option kbuild: move Documentation to vmlinux-alldirs kbuild: move samples/ to KBUILD_VMLINUX_OBJS modpost: make KBUILD_MODPOST_WARN also configurable for external modules kbuild: check arch/$(SRCARCH)/include/generated before out-of-tree build kbuild: remove unneeded dependency for include/config/kernel.release memory: squash drivers/memory/Makefile.asm-offsets kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree build kbuild: mkmakefile: generate a simple wrapper of top Makefile kbuild: mkmakefile: do not check the generated Makefile marker kbuild: allow Kbuild to start from any directory kbuild: pass $(MAKECMDGOALS) to sub-make as is kbuild: fix warning "overriding recipe for target 'Makefile'" ...
2019-04-03objtool: Add UACCESS validationPeter Zijlstra
It is important that UACCESS regions are as small as possible; furthermore the UACCESS state is not scheduled, so doing anything that might directly call into the scheduler will cause random code to be ran with UACCESS enabled. Teach objtool too track UACCESS state and warn about any CALL made while UACCESS is enabled. This very much includes the __fentry__() and __preempt_schedule() calls. Note that exceptions _do_ save/restore the UACCESS state, and therefore they can drive preemption. This also means that all exception handlers must have an otherwise redundant UACCESS disable instruction; therefore ignore this warning for !STT_FUNC code (exception handlers are not normal functions). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-02kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree buildMasahiro Yamada
KBUILD_SRC was conventionally used for some different purposes: [1] To remember the source tree path [2] As a flag to check if sub-make is already done [3] As a flag to check if Kbuild runs out of tree For [1], we do not need to remember it because the top Makefile can compute it by $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) [2] has been replaced with self-commenting 'sub_make_done'. For [3], we can distinguish in-tree/out-of-tree by comparing $(srctree) and '.' This commit converts [3] to prepare for the KBUILD_SRC removal. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-03-28kbuild: strip whitespace in cmd_record_mcount findstringJoe Lawrence
CC_FLAGS_FTRACE may contain trailing whitespace that interferes with findstring. For example, commit 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer") introduced a change such that on my ppc64le box, CC_FLAGS_FTRACE="-pg -mprofile-kernel ". (Note the trailing space.) When cmd_record_mcount is now invoked, findstring fails as the ftrace flags were found at very end of _c_flags, without the trailing space. _c_flags=" ... -pg -mprofile-kernel" CC_FLAGS_FTRACE="-pg -mprofile-kernel " ^ findstring is looking for this extra space Remove the redundant whitespaces from CC_FLAGS_FTRACE in cmd_record_mcount to avoid this problem. [masahiro.yamada: This issue only happens in the released versions of GNU Make. CC_FLAGS_FTRACE will not contain the trailing space if you use the latest GNU Make, which contains commit b90fabc8d6f3 ("* NEWS: Do not insert a space during '+=' if the value is empty.") ] Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> (refactoring) Fixes: 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer"). Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-03-14kbuild: move archive command to scripts/Makefile.libMasahiro Yamada
scripts/Makefile.build and arch/s390/boot/Makefile use the same command (thin archiving with symbol table creation). Avoid the code duplication, and move it to scripts/Makefile.lib. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-02-27kbuild: hardcode genksyms path and remove GENKSYMS variableMasahiro Yamada
The genksyms source was integrated into the kernel tree in 2003. I do not expect anybody still using the external /sbin/genksyms. Kbuild does not need to provide the ability to override GENKSYMS. Let's remove the GENKSYMS variable, and use the hardcoded path. Since it occurred in the pre-git era, I attached the commit message in case somebody is interested in the historical background. | Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de> | Date: Wed Feb 19 04:17:28 2003 -0600 | | kbuild: [PATCH] put genksyms in scripts dir | | This puts genksyms into scripts/genksyms/. | | genksyms used to be maintained externally, though the only possible user | was the kernel build. Moving it into the kernel sources makes it easier to | keep it uptodate, like for example updating it to generate linker scripts | directly instead of postprocessing the generated header file fragments | with sed, as we do currently. | | Also, genksyms does not handle __typeof__, which needs to be fixed since | some of the exported symbol in the kernel are defined using __typeof__. | | (Rusty Russell/me) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-02-20kbuild: generate modules.order only when CONFIG_MODULES=yMasahiro Yamada
Do not generate pointless modules.order when the module support is disabled. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-02-20kbuild: Disable extra debugging info in .s outputMasahiro Yamada
Modern gcc adds view assignments, reset assertion checking in .loc directives and a couple more additional debug markers, which clutters the asm output unnecessarily: For example: bsp_resume: .LFB3466: .loc 1 1868 1 is_stmt 1 view -0 .cfi_startproc .loc 1 1869 2 view .LVU73 # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) .loc 1 1869 14 is_stmt 0 view .LVU74 movq this_cpu(%rip), %rax # this_cpu, this_cpu movq 64(%rax), %rax # this_cpu.94_1->c_bsp_resume, _2 # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) .loc 1 1869 5 view .LVU75 testq %rax, %rax # _2 je .L8 #, .loc 1 1870 3 is_stmt 1 view .LVU76 movq $boot_cpu_data, %rdi #, jmp __x86_indirect_thunk_rax or .loc 2 57 9 view .LVU478 .loc 2 57 9 view .LVU479 .loc 2 57 9 view .LVU480 .loc 2 57 9 view .LVU481 .LBB1385: .LBB1383: .LBB1379: .LBB1377: .LBB1375: .loc 2 57 9 view .LVU482 .loc 2 57 9 view .LVU483 movl %edi, %edx # cpu, cpu .LVL87: .loc 2 57 9 is_stmt 0 view .LVU484 That MOV in there is drowned in debugging information and latter makes it hard to follow the asm. And that DWARF info is not really needed for asm output staring. Disable the debug information generation which clutters the asm output unnecessarily: bsp_resume: # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) movq this_cpu(%rip), %rax # this_cpu, this_cpu movq 64(%rax), %rax # this_cpu.94_1->c_bsp_resume, _2 # arch/x86/kernel/cpu/common.c:1869: if (this_cpu->c_bsp_resume) testq %rax, %rax # _2 je .L8 #, # arch/x86/kernel/cpu/common.c:1870: this_cpu->c_bsp_resume(&boot_cpu_data); movq $boot_cpu_data, %rdi #, jmp __x86_indirect_thunk_rax .L8: # arch/x86/kernel/cpu/common.c:1871: } rep ret .size bsp_resume, .-bsp_resume [ bp: write commit message. ] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Borislav Petkov <bp@suse.de>
2019-01-28kbuild: remove unnecessary in-subshell executionMasahiro Yamada
The commands surrounded by ( ) are executed in a subshell, but in most cases, we do not need to spawn an extra subshell. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-28kbuild: add real-prereqs shorthand for $(filter-out FORCE,$^)Masahiro Yamada
In Kbuild, if_changed and friends must have FORCE as a prerequisite. Hence, $(filter-out FORCE,$^) or $(filter-out $(PHONY),$^) is a common idiom to get the names of all the prerequisites except phony targets. Add real-prereqs as a shorthand. Note: We cannot replace $(filter %.o,$^) in cmd_link_multi-m because $^ may include auto-generated dependencies from the .*.cmd file when a single object module is changed into a multi object module. Refer to commit 69ea912fda74 ("kbuild: remove unneeded link_multi_deps"). I added some comment to avoid accidental breakage. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Rob Herring <robh@kernel.org>
2019-01-28kbuild: remove top-level built-in.aMasahiro Yamada
The symbol table in the final archive is unneeded; the linker does not require the symbol table after the --whole-archive option. Every object file in the archive is included in the link anyway. Pass thin archives from subdirectories directly to the linker, and remove the final archiving step. Fix up the document and comments as well. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Nicholas Piggin <npiggin@gmail.com>
2018-12-29Merge tag 'kbuild-v4.21' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "Kbuild core: - remove unneeded $(call cc-option,...) switches - consolidate Clang compiler flags into CLANG_FLAGS - announce the deprecation of SUBDIRS - fix single target build for external module - simplify the dependencies of 'prepare' stage targets - allow fixdep to directly write to .*.cmd files - simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS - change if_changed_rule to accept multi-line recipe - move .SECONDARY special target to scripts/Kbuild.include - remove redundant 'set -e' - improve parallel execution for CONFIG_HEADERS_CHECK - misc cleanups Treewide fixes and cleanups - set Clang flags correctly for PowerPC boot images - fix UML build error with CONFIG_GCC_PLUGINS - remove unneeded patterns from .gitignore files - refactor firmware/Makefile - remove unneeded rules for *offsets.s - avoid unneeded regeneration of intermediate .s files - clean up ./Kbuild Modpost: - remove unused -M, -K options - fix false positive warnings about section mismatch - use simple devtable lookup instead of linker magic - misc cleanups Coccinelle: - relax boolinit.cocci checks for overall consistency - fix warning messages of boolinit.cocci Other tools: - improve -dirty check of scripts/setlocalversion - add a tool to generate compile_commands.json from .*.cmd files" * tag 'kbuild-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (51 commits) kbuild: remove unused cmd_gentimeconst kbuild: remove $(obj)/ prefixes in ./Kbuild treewide: add intermediate .s files to targets treewide: remove explicit rules for *offsets.s firmware: refactor firmware/Makefile firmware: remove unnecessary patterns from .gitignore scripts: remove unnecessary ihex2fw and check-lc_ctypes from .gitignore um: remove unused filechk_gen_header in Makefile scripts: add a tool to produce a compile_commands.json file kbuild: add -Werror=implicit-int flag unconditionally kbuild: add -Werror=strict-prototypes flag unconditionally kbuild: add -fno-PIE flag unconditionally scripts: coccinelle: Correct warning message scripts: coccinelle: only suggest true/false in files that already use them kbuild: handle part-of-module correctly for *.ll and *.symtypes kbuild: refactor part-of-module kbuild: refactor quiet_modtag kbuild: remove redundant quiet_modtag for $(obj-m) kbuild: refactor Makefile.asm-generic user/Makefile: Fix typo and capitalization in comment section ...
2018-12-17kbuild: handle part-of-module correctly for *.ll and *.symtypesMasahiro Yamada
The single targets *.ll and *.symtypes have never been treated as a module. Fix it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-17kbuild: refactor part-of-moduleMasahiro Yamada
Use $(foreach ...) to make it shorter. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-17kbuild: refactor quiet_modtagMasahiro Yamada
part-of-module and quiet_modtag are set for the same targets. Define quiet_modtag based on part-of-module. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-17kbuild: remove redundant quiet_modtag for $(obj-m)Masahiro Yamada
All objects in $(obj-m) are contained in $(real-obj-m) as well. It is true composite objects are only contained in $(obj-m), but [M] is hard-coded in quiet_cmd_link_multi-m. This line is redundant. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-02kbuild: move .SECONDARY special target to Kbuild.includeMasahiro Yamada
In commit 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers"), I missed one important feature of the .SECONDARY target: .SECONDARY with no prerequisites causes all targets to be treated as secondary. ... which agrees with the policy of Kbuild. Let's move it to scripts/Kbuild.include, with no prerequisites. Note: If an intermediate file is generated by $(call if_changed,...), you still need to add it to "targets" so its .*.cmd file is included. The arm/arm64 crypto files are generated by $(call cmd,shipped), so they do not need to be added to "targets", but need to be added to "clean-files" so "make clean" can properly clean them away. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01kbuild: remove redundant 'set -e' from cmd_* definesMasahiro Yamada
These three cmd_* are invoked in the $(call cmd,*) form. Now that 'set -e' moved to the 'cmd' macro, they do not need to explicitly give 'set -e'. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01kbuild: remove trailing semicolon from cmd_* passed to if_changed_ruleMasahiro Yamada
With the change of rule_cc_o_c / rule_as_o_S in the last commit, each command is executed in a separate subshell. Rip off unneeded semicolons. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01kbuild: change if_changed_rule for multi-line recipeMasahiro Yamada
The 'define' ... 'endef' directive is useful to confine a series of shell commands into a single macro: define foo [action1] [action2] [action3] endif Each action is executed in a separate subshell. However, rule_cc_o_c and rule_as_o_S in scripts/Makefile.build are written as follows (with a trailing semicolon in each cmd_*): define rule_cc_o_c [action1] ; \ [action2] ; \ [action3] ; endef All shell commands are concatenated with '; \' so that it looks like a single command from the Makefile point of view. This does not exploit the benefits of 'define' ... 'endef' form because a single shell command can be more simply written, like this: rule_cc_o_c = \ [action1] ; \ [action2] ; \ [action3] ; I guess the intention for the command concatenation was to let the '@set -e' in if_changed_rule cover all the commands. We can improve the readability by moving '@set -e' to the 'cmd' macro. The combo of $(call echo-cmd,*) $(cmd_*) in rule_cc_o_c and rule_as_o_S have been replaced with $(call cmd,*). The trailing back-slashes have been removed. Here is a note about the performance: the commands in rule_cc_o_c and rule_as_o_S were previously executed all together in a single subshell, but now each line in a separate subshell. This means Make will spawn extra subshells [1]. I measured the build performance for x86_64_defconfig + CONFIG_MODVERSIONS + CONFIG_TRIM_UNUSED_KSYMS and I saw slight performance regression, but I believe code readability and maintainability wins. [1] Precisely, GNU Make may optimize this by executing the command directly instead of forking a subshell, if no shell special characters are found in the command line and omitting the subshell will not change the behavior. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMSMasahiro Yamada
My main motivation of this commit is to clean up scripts/Kbuild.include and scripts/Makefile.build. Currently, CONFIG_TRIM_UNUSED_KSYMS works with a tricky gimmick; possibly exported symbols are detected by letting $(CPP) replace EXPORT_SYMBOL* with a special string '=== __KSYM_*===', which is post-processed by sed, and passed to fixdep. The extra preprocessing is costly, and hacking cmd_and_fixdep is ugly. I came up with a new way to find exported symbols; insert a dummy symbol __ksym_marker_* to each potentially exported symbol. Those dummy symbols are picked up by $(NM), post-processed by sed, then appended to .*.cmd files. I collected the post-process part to a new shell script scripts/gen_ksymdeps.sh for readability. The dummy symbols are put into the .discard.* section so that the linker script rips them off the final vmlinux or modules. A nice side-effect is building with CONFIG_TRIM_UNUSED_KSYMS will be much faster. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nicolas Pitre <nico@linaro.org>
2018-12-01kbuild: refactor modversions build rulesMasahiro Yamada
Let $(CC) compile objects into normal files *.o instead of .tmp_*.o whether CONFIG_MODVERSIONS is enabled or not. With this, the input file for objtool is always *.o so objtool_o can go away. I guess the reason of using .tmp_*.o for intermediate objects was to avoid leaving incomplete *.o file (, whose timestamp says it is up-to-date) when the genksyms tool failed for some reasons. It no longer matters because any targets are deleted on errors since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01kbuild: remove redundant 'set -e' from sub_cmd_record_mcountMasahiro Yamada
This is executed inside the if_changed_rule, which already sets 'set -e'. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01kbuild: let fixdep directly write to .*.cmd filesMasahiro Yamada
Currently, fixdep writes dependencies to .*.tmp, which is renamed to .*.cmd after everything succeeds. This is a very safe way to avoid corrupted .*.cmd files. The if_changed_dep has carried this safety mechanism since it was added in 2002. If fixdep fails for some reasons or a user terminates the build while fixdep is running, the incomplete output from the fixdep could be troublesome. This is my insight about some bad scenarios: [1] If the compiler succeeds to generate *.o file, but fixdep fails to write necessary dependencies to .*.cmd file, Make will miss to rebuild the object when headers or CONFIG options are changed. In this case, fixdep should not generate .*.cmd file at all so that 'arg-check' will surely trigger the rebuild of the object. [2] A partially constructed .*.cmd file may not be a syntactically correct makefile. The next time Make runs, it would include it, then fail to parse it. Once this happens, 'make clean' is be the only way to fix it. In fact, [1] is no longer a problem since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"). Make deletes a target file on any failure in its recipe. Because fixdep is a part of the recipe of *.o target, if it fails, the *.o is deleted anyway. However, I am a bit worried about the slight possibility of [2]. So, here is a solution. Let fixdep directly write to a .*.cmd file, but allow makefiles to include it only when its corresponding target exists. This effectively reverts commit 2982c953570b ("kbuild: remove redundant $(wildcard ...) for cmd_files calculation"), and commit 00d78ab2ba75 ("kbuild: remove dead code in cmd_files calculation in top Makefile") because now we must check the presence of targets. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-11-28x86/retpoline: Make CONFIG_RETPOLINE depend on compiler supportZhenzhong Duan
Since retpoline capable compilers are widely available, make CONFIG_RETPOLINE hard depend on the compiler capability. Break the build when CONFIG_RETPOLINE is enabled and the compiler does not support it. Emit an error message in that case: "arch/x86/Makefile:226: *** You are building kernel with non-retpoline compiler, please update your compiler.. Stop." [dwmw: Fail the build with non-retpoline compiler] Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Borislav Petkov <bp@suse.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: <srinivas.eeda@oracle.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/cca0cb20-f9e2-4094-840b-fb0f8810cd34@default
2018-10-28Merge tag 'kbuild-v4.20' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - optimize kallsyms slightly - remove check for old CFLAGS usage - add some compiler flags unconditionally instead of evaluating $(call cc-option,...) - fix variable shadowing in host tools - refactor scripts/mkmakefile - refactor various makefiles * tag 'kbuild-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: modpost: Create macro to avoid variable shadowing ASN.1: Remove unnecessary shadowed local variable kbuild: use 'else ifeq' for checksrc to improve readability kbuild: remove unneeded link_multi_deps kbuild: add -Wno-unused-but-set-variable flag unconditionally kbuild: add -Wdeclaration-after-statement flag unconditionally kbuild: add -Wno-pointer-sign flag unconditionally modpost: remove leftover symbol prefix handling for module device table kbuild: simplify command line creation in scripts/mkmakefile kbuild: do not pass $(objtree) to scripts/mkmakefile kbuild: remove user ID check in scripts/mkmakefile kbuild: remove VERSION and PATCHLEVEL from $(objtree)/Makefile kbuild: add --include-dir flag only for out-of-tree build kbuild: remove dead code in cmd_files calculation in top Makefile kbuild: hide most of targets when running config or mixed targets kbuild: remove old check for CFLAGS use kbuild: prefix Makefile.dtbinst path with $(srctree) unconditionally kallsyms: remove left-over Blackfin code kallsyms: reduce size a little on 64-bit
2018-10-19kbuild: use 'else ifeq' for checksrc to improve readabilityMasahiro Yamada
'ifeq ... else ifeq ... endif' notation is supported by GNU Make 3.81 or later, which is the requirement for building the kernel since commit 37d69ee30808 ("docs: bump minimal GNU Make version to 3.81"). Use it to improve the readability. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-10-19kbuild: remove unneeded link_multi_depsMasahiro Yamada
Since commit c8589d1e9e01 ("kbuild: handle multi-objs dependency appropriately"), $^ really represents all the prerequisite of the composite object being built. Hence, $(filter %.o,$^) contains all the objects to link together, which is much simpler than link_multi_deps calculation. Please note $(filter-out FORCE,$^) does not work here. When a single object module is turned into a multi object module, $^ will contain header files that were previously included for building the single object, and recorded in the .*.cmd file. To filter out such headers, $(filter %.o,$^) should be used here. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-09-19ftrace: Build with CPPFLAGS to get -Qunused-argumentsJoel Stanley
When building to record the mcount locations the kernel uses KBUILD_CFLAGS but not KBUILD_CPPFLAGS. This means it lacks -Qunused-arguments when building with clang, resulting in a lot of noisy warnings. Signed-off-by: Joel Stanley <joel@jms.id.au> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-09-13kbuild: remove old check for CFLAGS useMasahiro Yamada
This check has been here for more than a decade since commit 0c53c8e6eb45 ("kbuild: check for wrong use of CFLAGS"). Enough time for migration has passed. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-08-30objtool: Remove workaround for unreachable warnings from old GCCMasahiro Yamada
Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") bumped the minimum GCC version to 4.6 for all architectures. This effectively reverts commit da541b20021c ("objtool: Skip unreachable warnings for GCC 4.4 and older"), which was a workaround for GCC 4.4 or older. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: linux-kbuild@vger.kernel.org Link: https://lkml.kernel.org/r/1535341183-19994-1-git-send-email-yamada.masahiro@socionext.com
2018-08-24kbuild: rename LDFLAGS to KBUILD_LDFLAGSMasahiro Yamada
Commit a0f97e06a43c ("kbuild: enable 'make CFLAGS=...' to add additional options to CC") renamed CFLAGS to KBUILD_CFLAGS. Commit 222d394d30e7 ("kbuild: enable 'make AFLAGS=...' to add additional options to AS") renamed AFLAGS to KBUILD_AFLAGS. Commit 06c5040cdb13 ("kbuild: enable 'make CPPFLAGS=...' to add additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS. For some reason, LDFLAGS was not renamed. Using a well-known variable like LDFLAGS may result in accidental override of the variable. Kbuild generally uses KBUILD_ prefixed variables for the internally appended options, so here is one more conversion to sanitize the naming convention. I did not touch Makefiles under tools/ since the tools build system is a different world. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
2018-08-24kbuild: pass LDFLAGS to recordmcount.plMasahiro Yamada
Since commit 0fbe9a245c60 ("microblaze: add endianness options to LDFLAGS instead of LD"), you cannot build the kernel for microblaze with CONFIG_DYNAMIC_FTRACE. Fixes: 0fbe9a245c60 ("microblaze: add endianness options to LDFLAGS instead of LD") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-08-20Merge tag 'trace-v4.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - Restructure of lockdep and latency tracers This is the biggest change. Joel Fernandes restructured the hooks from irqs and preemption disabling and enabling. He got rid of a lot of the preprocessor #ifdef mess that they caused. He turned both lockdep and the latency tracers to use trace events inserted in the preempt/irqs disabling paths. But unfortunately, these started to cause issues in corner cases. Thus, parts of the code was reverted back to where lockdep and the latency tracers just get called directly (without using the trace events). But because the original change cleaned up the code very nicely we kept that, as well as the trace events for preempt and irqs disabling, but they are limited to not being called in NMIs. - Have trace events use SRCU for "rcu idle" calls. This was required for the preempt/irqs off trace events. But it also had to not allow them to be called in NMI context. Waiting till Paul makes an NMI safe SRCU API. - New notrace SRCU API to allow trace events to use SRCU. - Addition of mcount-nop option support - SPDX headers replacing GPL templates. - Various other fixes and clean ups. - Some fixes are marked for stable, but were not fully tested before the merge window opened. * tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits) tracing: Fix SPDX format headers to use C++ style comments tracing: Add SPDX License format tags to tracing files tracing: Add SPDX License format to bpf_trace.c blktrace: Add SPDX License format header s390/ftrace: Add -mfentry and -mnop-mcount support tracing: Add -mcount-nop option support tracing: Avoid calling cc-option -mrecord-mcount for every Makefile tracing: Handle CC_FLAGS_FTRACE more accurately Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Uprobes: Simplify uprobe_register() body tracepoints: Free early tracepoints after RCU is initialized uprobes: Use synchronize_rcu() not synchronize_sched() tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister() ftrace: Remove unused pointer ftrace_swapper_pid tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing/irqsoff: Handle preempt_count for different configs tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing: irqsoff: Account for additional preempt_disable trace: Use rcu_dereference_raw for hooks from trace-event subsystem tracing/kprobes: Fix within_notrace_func() to check only notrace functions ...
2018-08-15tracing: Avoid calling cc-option -mrecord-mcount for every MakefileVasily Gorbik
Currently if CONFIG_FTRACE_MCOUNT_RECORD is enabled -mrecord-mcount compiler flag support is tested for every Makefile. Top 4 cc-option usages: 511 -mrecord-mcount 11 -fno-stack-protector 9 -Wno-override-init 2 -fsched-pressure To address that move cc-option from scripts/Makefile.build to top Makefile and export CC_USING_RECORD_MCOUNT to be used in original place. While doing that also add -mrecord-mcount to CC_FLAGS_FTRACE (if gcc actually supports it). Link: http://lkml.kernel.org/r/patch-2.thread-aa7b8d.git-de935bace15a.your-ad-here.call-01533557518-ext-9465@work.hours Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-08-09kbuild: remove deprecated host-progs variableMasahiro Yamada
The host-progs has been kept as an alias of hostprogs-y for a long time (at least since the beginning of Git era), with the clear prompt: Usage of host-progs is deprecated. Please replace with hostprogs-y! Enough time for the migration has passed. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com>
2018-07-06kbuild: remove duplicated comments about PHONYMasahiro Yamada
The comment is the same as in the top-level Makefile. Also, the comments contain typos: - the .PHONY variable -> the PHONY variable - se we can ... -> so we can ... Instead of fixing the typos, just remove the duplicated comments. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-06-21tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcountGreg Thelen
Non gcc-5 builds with CONFIG_STACK_VALIDATION=y and SKIP_STACK_VALIDATION=1 fail. Example output: /bin/sh: init/.tmp_main.o: Permission denied commit 96f60dfa5819 ("trace: Use -mcount-record for dynamic ftrace"), added a mismatched endif. This causes cmd_objtool to get mistakenly set. Relocate endif to balance the newly added -record-mcount check. Link: http://lkml.kernel.org/r/20180608214746.136554-1-gthelen@google.com Fixes: 96f60dfa5819 ("trace: Use -mcount-record for dynamic ftrace") Acked-by: Andi Kleen <ak@linux.intel.com> Tested-by: David Rientjes <rientjes@google.com> Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-06-06Merge tag 'trace-v4.18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "One new feature was added to ftrace, which is the trace_marker now supports triggers. For example: # cd /sys/kernel/debug/tracing # echo 'snapshot' > events/ftrace/print/trigger # echo 'cause snapshot' > trace_marker The rest of the changes are various clean ups and also one stable fix that was added late in the cycle" * tag 'trace-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (21 commits) tracing: Use match_string() instead of open coding it in trace_set_options() branch-check: fix long->int truncation when profiling branches ring-buffer: Fix typo in comment ring-buffer: Fix a bunch of typos in comments tracing/selftest: Add test to test simple snapshot trigger for trace_marker tracing/selftest: Add test to test hist trigger between kernel event and trace_marker tracing/selftest: Add selftests to test trace_marker histogram triggers ftrace/selftest: Fix reset_trigger() to handle triggers with filters ftrace/selftest: Have the reset_trigger code be a bit more careful tracing: Document trace_marker triggers tracing: Allow histogram triggers to access ftrace internal events tracing: Prevent further users of zero size static arrays in trace events tracing: Have zero size length in filter logic be full string tracing: Add trigger file for trace_markers tracefs/ftrace/print tracing: Do not show filter file for ftrace internal events tracing: Add brackets in ftrace event dynamic arrays tracing: Have event_trace_init() called by trace_init_tracefs() tracing: Add __find_event_file() to find event files without restrictions tracing: Do not reference event data in post call triggers tracepoints: Fix the descriptions of tracepoint_probe_register{_prio} ...
2018-05-28trace: Use -mcount-record for dynamic ftraceAndi Kleen
gcc 5 supports a new -mcount-record option to generate ftrace tables directly. This avoids the need to run record_mcount manually. Use this option when available. So far doesn't use -mcount-nop, which also exists now. This is needed to make ftrace work with LTO because the normal record-mcount script doesn't run over the link time output. It should also improve build times slightly in the general case. Link: http://lkml.kernel.org/r/20171127213423.27218-12-andi@firstfloor.org Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-05-17kbuild: remove CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIXMasahiro Yamada
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG. They were removed by commit 4ba66a976072 ("arch: remove blackfin port"), commit bb6fb6dfcc17 ("metag: Remove arch/metag/"), respectively. No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX. Clean up the rest of scripts, and remove the Kconfig entry. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
2018-05-17genksyms: remove symbol prefix supportMasahiro Yamada
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX was selected by BLACKFIN, METAG. They were removed by commit 4ba66a976072 ("arch: remove blackfin port"), commit bb6fb6dfcc17 ("metag: Remove arch/metag/"), respectively. No more architecture enables CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX, hence the -s (--symbol-prefix) option is unnecessary. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
2018-04-07kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markersMasahiro Yamada
GNU Make automatically deletes intermediate files that are updated in a chain of pattern rules. Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts Example 2) %.o <- %.c <- %.c_shipped A couple of makefiles mark such targets as .PRECIOUS to prevent Make from deleting them, but the correct way is to use .SECONDARY. .SECONDARY Prerequisites of this special target are treated as intermediate files but are never automatically deleted. .PRECIOUS When make is interrupted during execution, it may delete the target file it is updating if the file was modified since make started. If you mark the file as precious, make will never delete the file if interrupted. Both can avoid deletion of intermediate files, but the difference is the behavior when Make is interrupted; .SECONDARY deletes the target, but .PRECIOUS does not. The use of .PRECIOUS is relatively rare since we do not want to keep partially constructed (possibly corrupted) targets. Another difference is that .PRECIOUS works with pattern rules whereas .SECONDARY does not. .PRECIOUS: $(obj)/%.lex.c works, but .SECONDARY: $(obj)/%.lex.c has no effect. However, for the reason above, I do not want to use .PRECIOUS which could cause obscure build breakage. The targets specified as .SECONDARY must be explicit. $(targets) contains all targets that need to include .*.cmd files. So, the intermediates you want to keep are mostly in there. Therefore, mark $(targets) as .SECONDARY. It means primary targets are also marked as .SECONDARY, but I do not see any drawback for this. I replaced some .SECONDARY / .PRECIOUS markers with 'targets'. This will make Kbuild search for non-existing .*.cmd files, but this is not a noticeable performance issue. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com> Acked-by: Ingo Molnar <mingo@kernel.org>
2018-04-07kbuild: rename *-asn1.[ch] to *.asn1.[ch]Masahiro Yamada
Our convention is to distinguish file types by suffixes with a period as a separator. *-asn1.[ch] is a different pattern from other generated sources such as *.lex.c, *.tab.[ch], *.dtb.S, etc. More confusing, files with '-asn1.[ch]' are generated files, but '_asn1.[ch]' are checked-in files: net/netfilter/nf_conntrack_h323_asn1.c include/linux/netfilter/nf_conntrack_h323_asn1.h include/linux/sunrpc/gss_asn1.h Rename generated files to *.asn1.[ch] for consistency. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-04-07kbuild: add %.dtb.S and %.dtb to 'targets' automaticallyMasahiro Yamada
Another common pattern that consists of chained commands is to compile a DTB as binary data into the kernel image or a module. It is used in several places in the source tree. Support it in the core Makefile. $(call if_changed,dt_S_dtb) is more suitable than $(call cmd,dt_S_dtb) in case cmd_dt_S_dtb is changed in the future. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com>