From a1af8d71f0e4c6c23eb809de559150bbff296f4d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 27 Feb 2020 02:53:25 +0900 Subject: kbuild: remove trailing slash from devicetree/binding/ for descending obj-* needs a trailing slash for a directory, but subdir-* does not because it already implies a directory. Also, change subdir-y to subdir- to ensure this is effective only for cleaning targets. This makes the cleaning log consistent. (no trailing slash) Before: $ make clean CLEAN Documentation/devicetree/bindings/ After: $ make clean CLEAN Documentation/devicetree/bindings Signed-off-by: Masahiro Yamada --- Documentation/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/Makefile b/Documentation/Makefile index d77bb607aea4..39569a2e1953 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -2,7 +2,8 @@ # Makefile for Sphinx documentation # -subdir-y := devicetree/bindings/ +# for cleaning +subdir- := devicetree/bindings # Check for broken documentation file references ifeq ($(CONFIG_WARN_MISSING_DOCUMENTS),y) -- cgit v1.2.3 From fcf1b6a35c16ac500fa908a4022238e5d666eabf Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Wed, 26 Feb 2020 15:23:36 -0800 Subject: Documentation/llvm: add documentation on building w/ Clang/LLVM Added to kbuild documentation. Provides more official info on building kernels with Clang and LLVM than our wiki. Suggested-by: Kees Cook Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Reviewed-by: Sedat Dilek Signed-off-by: Nick Desaulniers Signed-off-by: Masahiro Yamada --- Documentation/kbuild/index.rst | 1 + Documentation/kbuild/llvm.rst | 80 ++++++++++++++++++++++++++++++++++++++++++ MAINTAINERS | 1 + 3 files changed, 82 insertions(+) create mode 100644 Documentation/kbuild/llvm.rst (limited to 'Documentation') diff --git a/Documentation/kbuild/index.rst b/Documentation/kbuild/index.rst index 0f144fad99a6..3882bd5f7728 100644 --- a/Documentation/kbuild/index.rst +++ b/Documentation/kbuild/index.rst @@ -19,6 +19,7 @@ Kernel Build System issues reproducible-builds + llvm .. only:: subproject and html diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst new file mode 100644 index 000000000000..d6c79eb4e23e --- /dev/null +++ b/Documentation/kbuild/llvm.rst @@ -0,0 +1,80 @@ +============================== +Building Linux with Clang/LLVM +============================== + +This document covers how to build the Linux kernel with Clang and LLVM +utilities. + +About +----- + +The Linux kernel has always traditionally been compiled with GNU toolchains +such as GCC and binutils. Ongoing work has allowed for `Clang +`_ and `LLVM `_ utilities to be +used as viable substitutes. Distributions such as `Android +`_, `ChromeOS +`_, and `OpenMandriva +`_ use Clang built kernels. `LLVM is a +collection of toolchain components implemented in terms of C++ objects +`_. Clang is a front-end to LLVM that +supports C and the GNU C extensions required by the kernel, and is pronounced +"klang," not "see-lang." + +Clang +----- + +The compiler used can be swapped out via `CC=` command line argument to `make`. +`CC=` should be set when selecting a config and during a build. + + make CC=clang defconfig + + make CC=clang + +Cross Compiling +--------------- + +A single Clang compiler binary will typically contain all supported backends, +which can help simplify cross compiling. + + ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang + +`CROSS_COMPILE` is not used to prefix the Clang compiler binary, instead +`CROSS_COMPILE` is used to set a command line flag: `--target `. For +example: + + clang --target aarch64-linux-gnu foo.c + +LLVM Utilities +-------------- + +LLVM has substitutes for GNU binutils utilities. These can be invoked as +additional parameters to `make`. + + make CC=clang AS=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\ + OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-objsize \\ + READELF=llvm-readelf HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar \\ + HOSTLD=ld.lld + +Getting Help +------------ + +- `Website `_ +- `Mailing List `_: +- `Issue Tracker `_ +- IRC: #clangbuiltlinux on chat.freenode.net +- `Telegram `_: @ClangBuiltLinux +- `Wiki `_ +- `Beginner Bugs `_ + +Getting LLVM +------------- + +- http://releases.llvm.org/download.html +- https://github.com/llvm/llvm-project +- https://llvm.org/docs/GettingStarted.html +- https://llvm.org/docs/CMake.html +- https://apt.llvm.org/ +- https://www.archlinux.org/packages/extra/x86_64/llvm/ +- https://github.com/ClangBuiltLinux/tc-build +- https://github.com/ClangBuiltLinux/linux/wiki/Building-Clang-from-source +- https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/ diff --git a/MAINTAINERS b/MAINTAINERS index 6158a143a13e..b6c6f3eee93c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -4119,6 +4119,7 @@ B: https://github.com/ClangBuiltLinux/linux/issues C: irc://chat.freenode.net/clangbuiltlinux S: Supported K: \b(?i:clang|llvm)\b +F: Documentation/kbuild/llvm.rst CLEANCACHE API M: Konrad Rzeszutek Wilk -- cgit v1.2.3 From 2ba06cd8565b5b3dee33a9ca24cf86a906d051d1 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Fri, 28 Feb 2020 18:37:30 -0600 Subject: kbuild: Always validate DT binding examples Most folks only run dt_binding_check on the single schema they care about by setting DT_SCHEMA_FILES. That means example is only checked against that one schema which is not always sufficient. Let's address this by splitting processed-schema.yaml into 2 files: one that's always all schemas for the examples and one that's just the schema in DT_SCHEMA_FILES for dtbs. Co-developed-by: Masahiro Yamada Signed-off-by: Rob Herring Signed-off-by: Masahiro Yamada --- Documentation/devicetree/bindings/.gitignore | 2 +- Documentation/devicetree/bindings/Makefile | 22 ++++++++++++++-------- scripts/Makefile.lib | 3 ++- 3 files changed, 17 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/.gitignore b/Documentation/devicetree/bindings/.gitignore index ef82fcfcccab..57afa1533a5f 100644 --- a/Documentation/devicetree/bindings/.gitignore +++ b/Documentation/devicetree/bindings/.gitignore @@ -1,2 +1,2 @@ *.example.dts -processed-schema.yaml +processed-schema*.yaml diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile index 646cb3525373..7c40d5ba1b51 100644 --- a/Documentation/devicetree/bindings/Makefile +++ b/Documentation/devicetree/bindings/Makefile @@ -2,7 +2,6 @@ DT_DOC_CHECKER ?= dt-doc-validate DT_EXTRACT_EX ?= dt-extract-example DT_MK_SCHEMA ?= dt-mk-schema -DT_MK_SCHEMA_FLAGS := $(if $(DT_SCHEMA_FILES), -u) quiet_cmd_chk_binding = CHKDT $(patsubst $(srctree)/%,%,$<) cmd_chk_binding = $(DT_DOC_CHECKER) -u $(srctree)/$(src) $< ; \ @@ -11,26 +10,33 @@ quiet_cmd_chk_binding = CHKDT $(patsubst $(srctree)/%,%,$<) $(obj)/%.example.dts: $(src)/%.yaml FORCE $(call if_changed,chk_binding) -DT_TMP_SCHEMA := processed-schema.yaml +# Use full schemas when checking %.example.dts +DT_TMP_SCHEMA := $(obj)/processed-schema-examples.yaml quiet_cmd_mk_schema = SCHEMA $@ cmd_mk_schema = $(DT_MK_SCHEMA) $(DT_MK_SCHEMA_FLAGS) -o $@ $(real-prereqs) -DT_DOCS = $(shell \ +DT_DOCS = $(addprefix $(src)/, \ + $(shell \ cd $(srctree)/$(src) && \ find * \( -name '*.yaml' ! \ - -name $(DT_TMP_SCHEMA) ! \ + -name 'processed-schema*' ! \ -name '*.example.dt.yaml' \) \ - ) + )) -DT_SCHEMA_FILES ?= $(addprefix $(src)/,$(DT_DOCS)) +DT_SCHEMA_FILES ?= $(DT_DOCS) ifeq ($(CHECK_DTBS),) extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES)) extra-y += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES)) +extra-y += processed-schema-examples.yaml + +$(obj)/processed-schema-examples.yaml: $(DT_DOCS) FORCE + $(call if_changed,mk_schema) endif -$(obj)/$(DT_TMP_SCHEMA): $(DT_SCHEMA_FILES) FORCE +$(obj)/processed-schema.yaml: DT_MK_SCHEMA_FLAGS := -u +$(obj)/processed-schema.yaml: $(DT_SCHEMA_FILES) FORCE $(call if_changed,mk_schema) -extra-y += $(DT_TMP_SCHEMA) +extra-y += processed-schema.yaml diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 752ff0a225a9..97547108ee7f 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -297,7 +297,8 @@ $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE DT_CHECKER ?= dt-validate DT_BINDING_DIR := Documentation/devicetree/bindings -DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.yaml +# DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile +DT_TMP_SCHEMA ?= $(objtree)/$(DT_BINDING_DIR)/processed-schema.yaml quiet_cmd_dtb_check = CHECK $@ cmd_dtb_check = $(DT_CHECKER) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@ -- cgit v1.2.3 From 65220630bb1766227c29a7774b95af3916f1564b Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Fri, 28 Feb 2020 18:37:31 -0600 Subject: kbuild: Build DT binding examples with dtc warnings enabled Now that we have a separate rule for DT binding examples, we can customize the dtc options. Let's adjust the dtc warnings to me more strict by default so the examples get cleaned up as they get converted to schema. Leaving 'avoid_unnecessary_addr_size' and 'graph_child_address' warnings disabled as examples tend to be incomplete and they generates a lot of warnings. Co-developed-by: Masahiro Yamada Signed-off-by: Rob Herring Signed-off-by: Masahiro Yamada --- Documentation/devicetree/bindings/Makefile | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile index 7c40d5ba1b51..b62c0470f122 100644 --- a/Documentation/devicetree/bindings/Makefile +++ b/Documentation/devicetree/bindings/Makefile @@ -31,6 +31,10 @@ extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES)) extra-y += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES)) extra-y += processed-schema-examples.yaml +override DTC_FLAGS := \ + -Wno-avoid_unnecessary_addr_size \ + -Wno-graph_child_address + $(obj)/processed-schema-examples.yaml: $(DT_DOCS) FORCE $(call if_changed,mk_schema) endif -- cgit v1.2.3 From e10c4321dc1e017e472c3fa40bb4e93355921e67 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 4 Mar 2020 12:20:37 +0900 Subject: kbuild: allow to run dt_binding_check and dtbs_check in a single command Since commit 93512dad334d ("dt-bindings: Improve validation build error handling"), 'make dtbs_check' does not validate the schema fully. If you want to check everything, you need to run two commands separately. $ make ARCH=arm dt_binding_check $ make ARCH=arm dtbs_check They are exclusive each other, so you cannot do like this: $ make ARCH=arm dt_binding_check dtbs_check In this case, dt-doc-validate and dt-extract-example are skipped because CHECK_DTBS is set. Let's make it possible to run these two targets in a single command. It will be useful for schema writers. Signed-off-by: Masahiro Yamada Reviewed-by: Rob Herring --- Documentation/devicetree/bindings/Makefile | 8 +++----- Documentation/devicetree/writing-schema.rst | 4 ++++ Makefile | 6 +++++- 3 files changed, 12 insertions(+), 6 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile index b62c0470f122..1df680d07461 100644 --- a/Documentation/devicetree/bindings/Makefile +++ b/Documentation/devicetree/bindings/Makefile @@ -26,10 +26,9 @@ DT_DOCS = $(addprefix $(src)/, \ DT_SCHEMA_FILES ?= $(DT_DOCS) -ifeq ($(CHECK_DTBS),) -extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES)) -extra-y += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES)) -extra-y += processed-schema-examples.yaml +extra-$(CHECK_DT_BINDING) += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES)) +extra-$(CHECK_DT_BINDING) += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES)) +extra-$(CHECK_DT_BINDING) += processed-schema-examples.yaml override DTC_FLAGS := \ -Wno-avoid_unnecessary_addr_size \ @@ -37,7 +36,6 @@ override DTC_FLAGS := \ $(obj)/processed-schema-examples.yaml: $(DT_DOCS) FORCE $(call if_changed,mk_schema) -endif $(obj)/processed-schema.yaml: DT_MK_SCHEMA_FLAGS := -u $(obj)/processed-schema.yaml: $(DT_SCHEMA_FILES) FORCE diff --git a/Documentation/devicetree/writing-schema.rst b/Documentation/devicetree/writing-schema.rst index 7635ab230456..220cf464ed77 100644 --- a/Documentation/devicetree/writing-schema.rst +++ b/Documentation/devicetree/writing-schema.rst @@ -147,6 +147,10 @@ Note that ``dtbs_check`` will skip any binding schema files with errors. It is necessary to use ``dt_binding_check`` to get all the validation errors in the binding schema files. +It is possible to run both in a single command:: + + make dt_binding_check dtbs_check + It is also possible to run checks with a single schema file by setting the ``DT_SCHEMA_FILES`` variable to a specific schema file. diff --git a/Makefile b/Makefile index da1966eacdce..9387c96ec874 100644 --- a/Makefile +++ b/Makefile @@ -1250,10 +1250,10 @@ dtbs: include/config/kernel.release scripts_dtc $(Q)$(MAKE) $(build)=$(dtstree) ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),) +export CHECK_DTBS=y dtbs: dt_binding_check endif -dtbs_check: export CHECK_DTBS=1 dtbs_check: dtbs dtbs_install: @@ -1269,6 +1269,10 @@ PHONY += scripts_dtc scripts_dtc: scripts_basic $(Q)$(MAKE) $(build)=scripts/dtc +ifneq ($(filter dt_binding_check, $(MAKECMDGOALS)),) +export CHECK_DT_BINDING=y +endif + PHONY += dt_binding_check dt_binding_check: scripts_dtc $(Q)$(MAKE) $(build)=Documentation/devicetree/bindings -- cgit v1.2.3 From def2fbffe62c00c330c7f41584a356001179c59c Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 2 Mar 2020 15:23:39 +0900 Subject: kconfig: allow symbols implied by y to become m The 'imply' keyword restricts a symbol to y or n, excluding m when it is implied by y. This is the original behavior since commit 237e3ad0f195 ("Kconfig: Introduce the "imply" keyword"). However, the author of this feature, Nicolas Pitre, stated that the 'imply' keyword should not impose any restrictions. (https://lkml.org/lkml/2020/2/19/714) I agree, and want to get rid of this tricky behavior. Suggested-by: Nicolas Pitre Signed-off-by: Masahiro Yamada Acked-by: Nicolas Pitre --- Documentation/kbuild/kconfig-language.rst | 12 +++++++++++- scripts/kconfig/symbol.c | 5 +---- 2 files changed, 12 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index d0111dd26410..d4d988aea679 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -173,7 +173,7 @@ applicable everywhere (see syntax). === === ============= ============== n y n N/m/y m y m M/y/n - y y y Y/n + y y y Y/m/n y n * N === === ============= ============== @@ -181,6 +181,16 @@ applicable everywhere (see syntax). ability to hook into a secondary subsystem while allowing the user to configure that subsystem out without also having to unset these drivers. + Note: If the combination of FOO=y and BAR=m causes a link error, + you can guard the function call with IS_REACHABLE():: + + foo_init() + { + if (IS_REACHABLE(CONFIG_BAZ)) + baz_register(&foo); + ... + } + - limiting menu display: "visible if" This attribute is only applicable to menu blocks, if the condition is diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c index 8d38b700b314..b101ef3c377a 100644 --- a/scripts/kconfig/symbol.c +++ b/scripts/kconfig/symbol.c @@ -401,8 +401,7 @@ void sym_calc_value(struct symbol *sym) sym_warn_unmet_dep(sym); newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri); } - if (newval.tri == mod && - (sym_get_type(sym) == S_BOOLEAN || sym->implied.tri == yes)) + if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN) newval.tri = yes; break; case S_STRING: @@ -484,8 +483,6 @@ bool sym_tristate_within_range(struct symbol *sym, tristate val) return false; if (sym->visible <= sym->rev_dep.tri) return false; - if (sym->implied.tri == yes && val == mod) - return false; if (sym_is_choice_value(sym) && sym->visible == yes) return val == yes; return val >= sym->rev_dep.tri && val <= sym->visible; -- cgit v1.2.3 From 3a9dd3ecb207b2cb8a4aabd12d20e43fa360b66d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 2 Mar 2020 15:23:40 +0900 Subject: kconfig: make 'imply' obey the direct dependency The 'imply' statement may create unmet direct dependency when the implied symbol depends on m. [Test Code] config FOO tristate "foo" imply BAZ config BAZ tristate "baz" depends on BAR config BAR def_tristate m config MODULES def_bool y option modules If you set FOO=y, BAZ is also promoted to y, which results in the following .config file: CONFIG_FOO=y CONFIG_BAZ=y CONFIG_BAR=m CONFIG_MODULES=y This does not meet the dependency 'BAZ depends on BAR'. Unlike 'select', what is worse, Kconfig never shows the 'WARNING: unmet direct dependencies detected for ...' for this case. Because 'imply' is considered to be weaker than 'depends on', Kconfig should take the direct dependency into account. For clarification, describe this case in kconfig-language.rst too. Signed-off-by: Masahiro Yamada Acked-by: Nicolas Pitre Tested-by: Geert Uytterhoeven --- Documentation/kbuild/kconfig-language.rst | 15 +++++++++++++-- scripts/kconfig/symbol.c | 4 +++- 2 files changed, 16 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst index d4d988aea679..a1601ec3317b 100644 --- a/Documentation/kbuild/kconfig-language.rst +++ b/Documentation/kbuild/kconfig-language.rst @@ -159,11 +159,11 @@ applicable everywhere (see syntax). Given the following example:: config FOO - tristate + tristate "foo" imply BAZ config BAZ - tristate + tristate "baz" depends on BAR The following values are possible: @@ -174,6 +174,9 @@ applicable everywhere (see syntax). n y n N/m/y m y m M/y/n y y y Y/m/n + n m n N/m + m m m M/n + y m n M/n y n * N === === ============= ============== @@ -191,6 +194,14 @@ applicable everywhere (see syntax). ... } + Note: If the feature provided by BAZ is highly desirable for FOO, + FOO should imply not only BAZ, but also its dependency BAR:: + + config FOO + tristate "foo" + imply BAR + imply BAZ + - limiting menu display: "visible if" This attribute is only applicable to menu blocks, if the condition is diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c index b101ef3c377a..3dc81397d003 100644 --- a/scripts/kconfig/symbol.c +++ b/scripts/kconfig/symbol.c @@ -221,7 +221,7 @@ static void sym_calc_visibility(struct symbol *sym) sym_set_changed(sym); } tri = no; - if (sym->implied.expr && sym->dir_dep.tri != no) + if (sym->implied.expr) tri = expr_calc_value(sym->implied.expr); if (tri == mod && sym_get_type(sym) == S_BOOLEAN) tri = yes; @@ -394,6 +394,8 @@ void sym_calc_value(struct symbol *sym) if (sym->implied.tri != no) { sym->flags |= SYMBOL_WRITE; newval.tri = EXPR_OR(newval.tri, sym->implied.tri); + newval.tri = EXPR_AND(newval.tri, + sym->dir_dep.tri); } } calc_newval: -- cgit v1.2.3