From ec873a4c551e2851adbafa27c89872255a891bf7 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 17 Sep 2024 23:16:38 +0900 Subject: kbuild: refactor the check for missing config files This commit refactors the check for missing configuration files, making it easier to add more files to the list. The format of the error message has been slightly changed, as follows: [Before] ERROR: Kernel configuration is invalid. include/generated/autoconf.h or include/config/auto.conf are missing. Run 'make oldconfig && make prepare' on kernel src to fix it. [After] *** *** ERROR: Kernel configuration is invalid. The following files are missing: *** - include/generated/autoconf.h *** - include/config/auto.conf *** Run "make oldconfig && make prepare" on kernel source to fix it. *** Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Miguel Ojeda --- Makefile | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index b8efbfe9da94..096b1e6cd965 100644 --- a/Makefile +++ b/Makefile @@ -781,17 +781,22 @@ $(KCONFIG_CONFIG): else # !may-sync-config # External modules and some install targets need include/generated/autoconf.h # and include/config/auto.conf but do not care if they are up-to-date. -# Use auto.conf to trigger the test +# Use auto.conf to show the error message + +checked-configs := include/generated/autoconf.h include/config/auto.conf +missing-configs := $(filter-out $(wildcard $(checked-configs)), $(checked-configs)) + +ifdef missing-configs PHONY += include/config/auto.conf include/config/auto.conf: - @test -e include/generated/autoconf.h -a -e $@ || ( \ - echo >&2; \ - echo >&2 " ERROR: Kernel configuration is invalid."; \ - echo >&2 " include/generated/autoconf.h or $@ are missing.";\ - echo >&2 " Run 'make oldconfig && make prepare' on kernel src to fix it."; \ - echo >&2 ; \ - /bin/false) + @echo >&2 '***' + @echo >&2 '*** ERROR: Kernel configuration is invalid. The following files are missing:' + @printf >&2 '*** - %s\n' $(missing-configs) + @echo >&2 '*** Run "make oldconfig && make prepare" on kernel source to fix it.' + @echo >&2 '***' + @/bin/false +endif endif # may-sync-config endif # need-config -- cgit v1.2.3 From 985d6cccb67c1943c687294095df04a031183fdb Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 17 Sep 2024 23:16:39 +0900 Subject: kbuild: check the presence of include/generated/rustc_cfg Since commit 2f7ab1267dc9 ("Kbuild: add Rust support"), Kconfig generates include/generated/rustc_cfg, but its presence is not checked in the top-level Makefile. It should be checked similarly to the C header counterpart, include/generated/autoconf.h. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Acked-by: Miguel Ojeda Tested-by: Miguel Ojeda --- Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 096b1e6cd965..9b30c42ce3b3 100644 --- a/Makefile +++ b/Makefile @@ -783,7 +783,7 @@ else # !may-sync-config # and include/config/auto.conf but do not care if they are up-to-date. # Use auto.conf to show the error message -checked-configs := include/generated/autoconf.h include/config/auto.conf +checked-configs := include/generated/autoconf.h include/generated/rustc_cfg include/config/auto.conf missing-configs := $(filter-out $(wildcard $(checked-configs)), $(checked-configs)) ifdef missing-configs @@ -1201,7 +1201,8 @@ PHONY += prepare archprepare archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \ asm-generic $(version_h) include/generated/utsrelease.h \ - include/generated/compile.h include/generated/autoconf.h remove-stale-files + include/generated/compile.h include/generated/autoconf.h \ + include/generated/rustc_cfg remove-stale-files prepare0: archprepare $(Q)$(MAKE) $(build)=scripts/mod -- cgit v1.2.3 From 654102df2ac2a0d02a416100c3d44ff1dae932ca Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 23 Sep 2024 16:56:03 +0900 Subject: kbuild: add generic support for built-in boot DTBs Some architectures embed boot DTBs in vmlinux. A potential issue for these architectures is a race condition during parallel builds because Kbuild descends into arch/*/boot/dts/ twice. One build thread is initiated by the 'dtbs' target, which is a prerequisite of the 'all' target in the top-level Makefile: ifdef CONFIG_OF_EARLY_FLATTREE all: dtbs endif For architectures that support the built-in boot dtb, arch/*/boot/dts/ is visited also during the ordinary directory traversal in order to build obj-y objects that wrap DTBs. Since these build threads are unaware of each other, they can run simultaneously during parallel builds. This commit introduces a generic build rule to scripts/Makefile.vmlinux to support embedded boot DTBs in a race-free way. Architectures that want to use this rule need to select CONFIG_GENERIC_BUILTIN_DTB. After the migration, Makefiles under arch/*/boot/dts/ will be visited only once to build only *.dtb files. This change also aims to unify the CONFIG options used for built-in DTBs support. Currently, different architectures use different CONFIG options for the same purposes. With this commit, the CONFIG options will be unified as follows: - CONFIG_GENERIC_BUILTIN_DTB This enables the generic rule for built-in boot DTBs. This will be renamed to CONFIG_BUILTIN_DTB after all architectures migrate to the generic rule. - CONFIG_BUILTIN_DTB_NAME This specifies the path to the embedded DTB. (relative to arch/*/boot/dts/) - CONFIG_BUILTIN_DTB_ALL If this is enabled, all DTB files compiled under arch/*/boot/dts/ are embedded into vmlinux. Only used by MIPS. Signed-off-by: Masahiro Yamada --- Makefile | 7 ++++++- drivers/of/Kconfig | 6 ++++++ scripts/Makefile.vmlinux | 44 ++++++++++++++++++++++++++++++++++++++++++++ scripts/link-vmlinux.sh | 4 ++++ 4 files changed, 60 insertions(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 9b30c42ce3b3..855913b71e7a 100644 --- a/Makefile +++ b/Makefile @@ -1433,6 +1433,10 @@ ifdef CONFIG_OF_EARLY_FLATTREE all: dtbs endif +ifdef CONFIG_GENERIC_BUILTIN_DTB +vmlinux: dtbs +endif + endif PHONY += scripts_dtc @@ -1500,7 +1504,8 @@ CLEAN_FILES += vmlinux.symvers modules-only.symvers \ modules.builtin modules.builtin.modinfo modules.nsdeps \ modules.builtin.ranges vmlinux.o.map \ compile_commands.json rust/test \ - rust-project.json .vmlinux.objs .vmlinux.export.c + rust-project.json .vmlinux.objs .vmlinux.export.c \ + .builtin-dtbs-list .builtin-dtb.S # Directories & files removed with 'make mrproper' MRPROPER_FILES += include/config include/generated \ diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index 0e2d608c3e20..6a53cbaa134c 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -2,6 +2,12 @@ config DTC bool +config GENERIC_BUILTIN_DTB + bool + +config BUILTIN_DTB_ALL + bool + menuconfig OF bool "Device Tree and Open Firmware support" help diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index 1284f05555b9..9ef0480ed755 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux @@ -17,6 +17,50 @@ quiet_cmd_cc_o_c = CC $@ %.o: %.c FORCE $(call if_changed_dep,cc_o_c) +quiet_cmd_as_o_S = AS $@ + cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< + +%.o: %.S FORCE + $(call if_changed_dep,as_o_S) + +# Built-in dtb +# --------------------------------------------------------------------------- + +quiet_cmd_wrap_dtbs = WRAP $@ + cmd_wrap_dtbs = { \ + echo '\#include '; \ + echo '.section .dtb.init.rodata,"a"'; \ + while read dtb; do \ + symbase=__dtb_$$(basename -s .dtb "$${dtb}" | tr - _); \ + echo '.balign STRUCT_ALIGNMENT'; \ + echo ".global $${symbase}_begin"; \ + echo "$${symbase}_begin:"; \ + echo '.incbin "'$$dtb'" '; \ + echo ".global $${symbase}_end"; \ + echo "$${symbase}_end:"; \ + done < $<; \ + } > $@ + +.builtin-dtbs.S: .builtin-dtbs-list FORCE + $(call if_changed,wrap_dtbs) + +quiet_cmd_gen_dtbs_list = GEN $@ + cmd_gen_dtbs_list = \ + $(if $(CONFIG_BUILTIN_DTB_NAME), echo "arch/$(SRCARCH)/boot/dts/$(CONFIG_BUILTIN_DTB_NAME).dtb",:) > $@ + +.builtin-dtbs-list: arch/$(SRCARCH)/boot/dts/dtbs-list FORCE + $(call if_changed,$(if $(CONFIG_BUILTIN_DTB_ALL),copy,gen_dtbs_list)) + +targets += .builtin-dtbs-list + +ifdef CONFIG_GENERIC_BUILTIN_DTB +targets += .builtin-dtbs.S .builtin-dtbs.o +vmlinux: .builtin-dtbs.o +endif + +# vmlinux +# --------------------------------------------------------------------------- + ifdef CONFIG_MODULES targets += .vmlinux.export.o vmlinux: .vmlinux.export.o diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index a9b3f34a78d2..53bd4b727e21 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -68,6 +68,10 @@ vmlinux_link() libs="${KBUILD_VMLINUX_LIBS}" fi + if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then + objs="${objs} .builtin-dtbs.o" + fi + if is_enabled CONFIG_MODULES; then objs="${objs} .vmlinux.export.o" fi -- cgit v1.2.3 From 397a479b511df4e6e7c665d7d8991943645b4cab Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 25 Oct 2024 02:09:22 +0900 Subject: kbuild: simplify rustfmt target There is no need to prune the rust/alloc directory because it was removed by commit 9d0441bab775 ("rust: alloc: remove our fork of the `alloc` crate"). There is no need to prune the rust/test directory because no '*.rs' files are generated within it. To avoid forking the 'grep -Fv generated' process, filter out generated files using the option, ! -name '*generated*'. Now that the '-path ... -prune' option is no longer used, there is no need to use the absolute path. Searching in $(srctree), which can be a relative path, is sufficient. The comment mentions the use case where $(srctree) is '..', that is, $(objtree) is a sub-directory of $(srctree). In this scenario, all '*.rs' files under $(objtree) are generated files and filters out by the '*generated*' pattern. Add $(RCS_FIND_IGNORE) as a shortcut. Although I do not believe '*.rs' files would exist under the .git directory, there is no need for the 'find' command to traverse it. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Acked-by: Miguel Ojeda --- Makefile | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 855913b71e7a..266376f7f164 100644 --- a/Makefile +++ b/Makefile @@ -1754,18 +1754,9 @@ rusttest: prepare # Formatting targets PHONY += rustfmt rustfmtcheck -# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream. -# -# We match using absolute paths since `find` does not resolve them -# when matching, which is a problem when e.g. `srctree` is `..`. -# We `grep` afterwards in order to remove the directory entry itself. rustfmt: - $(Q)find $(abs_srctree) -type f -name '*.rs' \ - -o -path $(abs_srctree)/rust/alloc -prune \ - -o -path $(abs_objtree)/rust/test -prune \ - | grep -Fv $(abs_srctree)/rust/alloc \ - | grep -Fv $(abs_objtree)/rust/test \ - | grep -Fv generated \ + $(Q)find $(srctree) $(RCS_FIND_IGNORE) \ + -type f -a -name '*.rs' -a ! -name '*generated*' -print \ | xargs $(RUSTFMT) $(rustfmt_flags) rustfmtcheck: rustfmt_flags = --check -- cgit v1.2.3 From 315ad8780a129e82e2c5c65ee6e970d91a577acb Mon Sep 17 00:00:00 2001 From: Rong Xu Date: Sat, 2 Nov 2024 10:51:08 -0700 Subject: kbuild: Add AutoFDO support for Clang build Add the build support for using Clang's AutoFDO. Building the kernel with AutoFDO does not reduce the optimization level from the compiler. AutoFDO uses hardware sampling to gather information about the frequency of execution of different code paths within a binary. This information is then used to guide the compiler's optimization decisions, resulting in a more efficient binary. Experiments showed that the kernel can improve up to 10% in latency. The support requires a Clang compiler after LLVM 17. This submission is limited to x86 platforms that support PMU features like LBR on Intel machines and AMD Zen3 BRS. Support for SPE on ARM 1, and BRBE on ARM 1 is part of planned future work. Here is an example workflow for AutoFDO kernel: 1) Build the kernel on the host machine with LLVM enabled, for example, $ make menuconfig LLVM=1 Turn on AutoFDO build config: CONFIG_AUTOFDO_CLANG=y With a configuration that has LLVM enabled, use the following command: scripts/config -e AUTOFDO_CLANG After getting the config, build with $ make LLVM=1 2) Install the kernel on the test machine. 3) Run the load tests. The '-c' option in perf specifies the sample event period. We suggest using a suitable prime number, like 500009, for this purpose. For Intel platforms: $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c \ -o -- For AMD platforms: The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2 For Zen3: $ cat proc/cpuinfo | grep " brs" For Zen4: $ cat proc/cpuinfo | grep amd_lbr_v2 $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \ -N -b -c -o -- 4) (Optional) Download the raw perf file to the host machine. 5) To generate an AutoFDO profile, two offline tools are available: create_llvm_prof and llvm_profgen. The create_llvm_prof tool is part of the AutoFDO project and can be found on GitHub (https://github.com/google/autofdo), version v0.30.1 or later. The llvm_profgen tool is included in the LLVM compiler itself. It's important to note that the version of llvm_profgen doesn't need to match the version of Clang. It needs to be the LLVM 19 release or later, or from the LLVM trunk. $ llvm-profgen --kernel --binary= --perfdata= \ -o or $ create_llvm_prof --binary= --profile= \ --format=extbinary --out= Note that multiple AutoFDO profile files can be merged into one via: $ llvm-profdata merge -o ... 6) Rebuild the kernel using the AutoFDO profile file with the same config as step 1, (Note CONFIG_AUTOFDO_CLANG needs to be enabled): $ make LLVM=1 CLANG_AUTOFDO_PROFILE= Co-developed-by: Han Shen Signed-off-by: Han Shen Signed-off-by: Rong Xu Suggested-by: Sriraman Tallam Suggested-by: Krzysztof Pszeniczny Suggested-by: Nick Desaulniers Suggested-by: Stephane Eranian Tested-by: Yonghong Song Tested-by: Yabin Cui Tested-by: Nathan Chancellor Reviewed-by: Kees Cook Tested-by: Peter Jung Signed-off-by: Masahiro Yamada --- Documentation/dev-tools/autofdo.rst | 168 ++++++++++++++++++++++++++++++++++++ Documentation/dev-tools/index.rst | 1 + MAINTAINERS | 7 ++ Makefile | 1 + arch/Kconfig | 20 +++++ arch/x86/Kconfig | 1 + scripts/Makefile.autofdo | 22 +++++ scripts/Makefile.lib | 10 +++ tools/objtool/check.c | 1 + 9 files changed, 231 insertions(+) create mode 100644 Documentation/dev-tools/autofdo.rst create mode 100644 scripts/Makefile.autofdo (limited to 'Makefile') diff --git a/Documentation/dev-tools/autofdo.rst b/Documentation/dev-tools/autofdo.rst new file mode 100644 index 000000000000..1f0a451e9ccd --- /dev/null +++ b/Documentation/dev-tools/autofdo.rst @@ -0,0 +1,168 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +Using AutoFDO with the Linux kernel +=================================== + +This enables AutoFDO build support for the kernel when using +the Clang compiler. AutoFDO (Auto-Feedback-Directed Optimization) +is a type of profile-guided optimization (PGO) used to enhance the +performance of binary executables. It gathers information about the +frequency of execution of various code paths within a binary using +hardware sampling. This data is then used to guide the compiler's +optimization decisions, resulting in a more efficient binary. AutoFDO +is a powerful optimization technique, and data indicates that it can +significantly improve kernel performance. It's especially beneficial +for workloads affected by front-end stalls. + +For AutoFDO builds, unlike non-FDO builds, the user must supply a +profile. Acquiring an AutoFDO profile can be done in several ways. +AutoFDO profiles are created by converting hardware sampling using +the "perf" tool. It is crucial that the workload used to create these +perf files is representative; they must exhibit runtime +characteristics similar to the workloads that are intended to be +optimized. Failure to do so will result in the compiler optimizing +for the wrong objective. + +The AutoFDO profile often encapsulates the program's behavior. If the +performance-critical codes are architecture-independent, the profile +can be applied across platforms to achieve performance gains. For +instance, using the profile generated on Intel architecture to build +a kernel for AMD architecture can also yield performance improvements. + +There are two methods for acquiring a representative profile: +(1) Sample real workloads using a production environment. +(2) Generate the profile using a representative load test. +When enabling the AutoFDO build configuration without providing an +AutoFDO profile, the compiler only modifies the dwarf information in +the kernel without impacting runtime performance. It's advisable to +use a kernel binary built with the same AutoFDO configuration to +collect the perf profile. While it's possible to use a kernel built +with different options, it may result in inferior performance. + +One can collect profiles using AutoFDO build for the previous kernel. +AutoFDO employs relative line numbers to match the profiles, offering +some tolerance for source changes. This mode is commonly used in a +production environment for profile collection. + +In a profile collection based on a load test, the AutoFDO collection +process consists of the following steps: + +#. Initial build: The kernel is built with AutoFDO options + without a profile. + +#. Profiling: The above kernel is then run with a representative + workload to gather execution frequency data. This data is + collected using hardware sampling, via perf. AutoFDO is most + effective on platforms supporting advanced PMU features like + LBR on Intel machines. + +#. AutoFDO profile generation: Perf output file is converted to + the AutoFDO profile via offline tools. + +The support requires a Clang compiler LLVM 17 or later. + +Preparation +=========== + +Configure the kernel with:: + + CONFIG_AUTOFDO_CLANG=y + +Customization +============= + +The default CONFIG_AUTOFDO_CLANG setting covers kernel space objects for +AutoFDO builds. One can, however, enable or disable AutoFDO build for +individual files and directories by adding a line similar to the following +to the respective kernel Makefile: + +- For enabling a single file (e.g. foo.o) :: + + AUTOFDO_PROFILE_foo.o := y + +- For enabling all files in one directory :: + + AUTOFDO_PROFILE := y + +- For disabling one file :: + + AUTOFDO_PROFILE_foo.o := n + +- For disabling all files in one directory :: + + AUTOFDO_PROFILE := n + +Workflow +======== + +Here is an example workflow for AutoFDO kernel: + +1) Build the kernel on the host machine with LLVM enabled, + for example, :: + + $ make menuconfig LLVM=1 + + Turn on AutoFDO build config:: + + CONFIG_AUTOFDO_CLANG=y + + With a configuration that with LLVM enabled, use the following command:: + + $ scripts/config -e AUTOFDO_CLANG + + After getting the config, build with :: + + $ make LLVM=1 + +2) Install the kernel on the test machine. + +3) Run the load tests. The '-c' option in perf specifies the sample + event period. We suggest using a suitable prime number, like 500009, + for this purpose. + + - For Intel platforms:: + + $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c -o -- + + - For AMD platforms: + + The supported systems are: Zen3 with BRS, or Zen4 with amd_lbr_v2. To check, + + For Zen3:: + + $ cat proc/cpuinfo | grep " brs" + + For Zen4:: + + $ cat proc/cpuinfo | grep amd_lbr_v2 + + The following command generated the perf data file:: + + $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c -o -- + +4) (Optional) Download the raw perf file to the host machine. + +5) To generate an AutoFDO profile, two offline tools are available: + create_llvm_prof and llvm_profgen. The create_llvm_prof tool is part + of the AutoFDO project and can be found on GitHub + (https://github.com/google/autofdo), version v0.30.1 or later. + The llvm_profgen tool is included in the LLVM compiler itself. It's + important to note that the version of llvm_profgen doesn't need to match + the version of Clang. It needs to be the LLVM 19 release of Clang + or later, or just from the LLVM trunk. :: + + $ llvm-profgen --kernel --binary= --perfdata= -o + + or :: + + $ create_llvm_prof --binary= --profile= --format=extbinary --out= + + Note that multiple AutoFDO profile files can be merged into one via:: + + $ llvm-profdata merge -o ... + +6) Rebuild the kernel using the AutoFDO profile file with the same config as step 1, + (Note CONFIG_AUTOFDO_CLANG needs to be enabled):: + + $ make LLVM=1 CLANG_AUTOFDO_PROFILE= diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index 53d4d124f9c5..6945644f7008 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -34,6 +34,7 @@ Documentation/dev-tools/testing-overview.rst ktap checkuapi gpio-sloppy-logic-analyzer + autofdo .. only:: subproject and html diff --git a/MAINTAINERS b/MAINTAINERS index bdae0faf000c..1eba172ed532 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3665,6 +3665,13 @@ F: kernel/audit* F: lib/*audit.c K: \baudit_[a-z_0-9]\+\b +AUTOFDO BUILD +M: Rong Xu +M: Han Shen +S: Supported +F: Documentation/dev-tools/autofdo.rst +F: scripts/Makefile.autofdo + AUXILIARY BUS DRIVER M: Greg Kroah-Hartman R: Dave Ertman diff --git a/Makefile b/Makefile index 266376f7f164..1f31c633a41d 100644 --- a/Makefile +++ b/Makefile @@ -1023,6 +1023,7 @@ include-$(CONFIG_KMSAN) += scripts/Makefile.kmsan include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan include-$(CONFIG_KCOV) += scripts/Makefile.kcov include-$(CONFIG_RANDSTRUCT) += scripts/Makefile.randstruct +include-$(CONFIG_AUTOFDO_CLANG) += scripts/Makefile.autofdo include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins include $(addprefix $(srctree)/, $(include-y)) diff --git a/arch/Kconfig b/arch/Kconfig index bd9f095d69fa..8dca3b5e6ef5 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -811,6 +811,26 @@ config LTO_CLANG_THIN If unsure, say Y. endchoice +config ARCH_SUPPORTS_AUTOFDO_CLANG + bool + +config AUTOFDO_CLANG + bool "Enable Clang's AutoFDO build (EXPERIMENTAL)" + depends on ARCH_SUPPORTS_AUTOFDO_CLANG + depends on CC_IS_CLANG && CLANG_VERSION >= 170000 + help + This option enables Clang’s AutoFDO build. When + an AutoFDO profile is specified in variable + CLANG_AUTOFDO_PROFILE during the build process, + Clang uses the profile to optimize the kernel. + + If no profile is specified, AutoFDO options are + still passed to Clang to facilitate the collection + of perf data for creating an AutoFDO profile in + subsequent builds. + + If unsure, say N. + config ARCH_SUPPORTS_CFI_CLANG bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 16354dfa6d96..9dc87661fb37 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -126,6 +126,7 @@ config X86 select ARCH_SUPPORTS_LTO_CLANG select ARCH_SUPPORTS_LTO_CLANG_THIN select ARCH_SUPPORTS_RT + select ARCH_SUPPORTS_AUTOFDO_CLANG select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64 select ARCH_USE_MEMTEST diff --git a/scripts/Makefile.autofdo b/scripts/Makefile.autofdo new file mode 100644 index 000000000000..ff96a63fea7c --- /dev/null +++ b/scripts/Makefile.autofdo @@ -0,0 +1,22 @@ +# SPDX-License-Identifier: GPL-2.0 + +# Enable available and selected Clang AutoFDO features. + +CFLAGS_AUTOFDO_CLANG := -fdebug-info-for-profiling -mllvm -enable-fs-discriminator=true -mllvm -improved-fs-discriminator=true + +ifndef CONFIG_DEBUG_INFO + CFLAGS_AUTOFDO_CLANG += -gmlt +endif + +ifdef CLANG_AUTOFDO_PROFILE + CFLAGS_AUTOFDO_CLANG += -fprofile-sample-use=$(CLANG_AUTOFDO_PROFILE) +endif + +ifdef CONFIG_LTO_CLANG_THIN + ifdef CLANG_AUTOFDO_PROFILE + KBUILD_LDFLAGS += --lto-sample-profile=$(CLANG_AUTOFDO_PROFILE) + endif + KBUILD_LDFLAGS += --mllvm=-enable-fs-discriminator=true --mllvm=-improved-fs-discriminator=true -plugin-opt=thinlto +endif + +export CFLAGS_AUTOFDO_CLANG diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 01a9f567d5af..2d0942c1a027 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -191,6 +191,16 @@ _c_flags += $(if $(patsubst n%,, \ -D__KCSAN_INSTRUMENT_BARRIERS__) endif +# +# Enable AutoFDO build flags except some files or directories we don't want to +# enable (depends on variables AUTOFDO_PROFILE_obj.o and AUTOFDO_PROFILE). +# +ifeq ($(CONFIG_AUTOFDO_CLANG),y) +_c_flags += $(if $(patsubst n%,, \ + $(AUTOFDO_PROFILE_$(target-stem).o)$(AUTOFDO_PROFILE)$(is-kernel-object)), \ + $(CFLAGS_AUTOFDO_CLANG)) +endif + # $(src) for including checkin headers from generated source files # $(obj) for including generated headers from checkin source files ifeq ($(KBUILD_EXTMOD),) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 6604f5d038aa..4c5229991e1e 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4557,6 +4557,7 @@ static int validate_ibt(struct objtool_file *file) !strcmp(sec->name, "__jump_table") || !strcmp(sec->name, "__mcount_loc") || !strcmp(sec->name, ".kcfi_traps") || + !strcmp(sec->name, ".llvm.call-graph-profile") || strstr(sec->name, "__patchable_function_entries")) continue; -- cgit v1.2.3 From d5dc95836147f2e25b134c0ca3a0bc1a5867ea29 Mon Sep 17 00:00:00 2001 From: Rong Xu Date: Sat, 2 Nov 2024 10:51:14 -0700 Subject: kbuild: Add Propeller configuration for kernel build MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add the build support for using Clang's Propeller optimizer. Like AutoFDO, Propeller uses hardware sampling to gather information about the frequency of execution of different code paths within a binary. This information is then used to guide the compiler's optimization decisions, resulting in a more efficient binary. The support requires a Clang compiler LLVM 19 or later, and the create_llvm_prof tool (https://github.com/google/autofdo/releases/tag/v0.30.1). This commit is limited to x86 platforms that support PMU features like LBR on Intel machines and AMD Zen3 BRS. Here is an example workflow for building an AutoFDO+Propeller optimized kernel: 1) Build the kernel on the host machine, with AutoFDO and Propeller build config CONFIG_AUTOFDO_CLANG=y CONFIG_PROPELLER_CLANG=y then $ make LLVM=1 CLANG_AUTOFDO_PROFILE= “” is the profile collected when doing a non-Propeller AutoFDO build. This step builds a kernel that has the same optimization level as AutoFDO, plus a metadata section that records basic block information. This kernel image runs as fast as an AutoFDO optimized kernel. 2) Install the kernel on test/production machines. 3) Run the load tests. The '-c' option in perf specifies the sample event period. We suggest using a suitable prime number, like 500009, for this purpose. For Intel platforms: $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c \ -o -- For AMD platforms: The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2 # To see if Zen3 support LBR: $ cat proc/cpuinfo | grep " brs" # To see if Zen4 support LBR: $ cat proc/cpuinfo | grep amd_lbr_v2 # If the result is yes, then collect the profile using: $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \ -N -b -c -o -- 4) (Optional) Download the raw perf file to the host machine. 5) Generate Propeller profile: $ create_llvm_prof --binary= --profile= \ --format=propeller --propeller_output_module_name \ --out=_cc_profile.txt \ --propeller_symorder=_ld_profile.txt “create_llvm_prof” is the profile conversion tool, and a prebuilt binary for linux can be found on https://github.com/google/autofdo/releases/tag/v0.30.1 (can also build from source). "" can be something like "/home/user/dir/any_string". This command generates a pair of Propeller profiles: "_cc_profile.txt" and "_ld_profile.txt". 6) Rebuild the kernel using the AutoFDO and Propeller profile files. CONFIG_AUTOFDO_CLANG=y CONFIG_PROPELLER_CLANG=y and $ make LLVM=1 CLANG_AUTOFDO_PROFILE= \ CLANG_PROPELLER_PROFILE_PREFIX= Co-developed-by: Han Shen Signed-off-by: Han Shen Signed-off-by: Rong Xu Suggested-by: Sriraman Tallam Suggested-by: Krzysztof Pszeniczny Suggested-by: Nick Desaulniers Suggested-by: Stephane Eranian Tested-by: Yonghong Song Tested-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Masahiro Yamada --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/propeller.rst | 162 ++++++++++++++++++++++++++++++++++ MAINTAINERS | 7 ++ Makefile | 1 + arch/Kconfig | 19 ++++ arch/x86/Kconfig | 1 + arch/x86/kernel/vmlinux.lds.S | 4 + include/asm-generic/vmlinux.lds.h | 6 +- scripts/Makefile.lib | 10 +++ scripts/Makefile.propeller | 28 ++++++ tools/objtool/check.c | 1 + 11 files changed, 237 insertions(+), 3 deletions(-) create mode 100644 Documentation/dev-tools/propeller.rst create mode 100644 scripts/Makefile.propeller (limited to 'Makefile') diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index 6945644f7008..3c0ac08b2709 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -35,6 +35,7 @@ Documentation/dev-tools/testing-overview.rst checkuapi gpio-sloppy-logic-analyzer autofdo + propeller .. only:: subproject and html diff --git a/Documentation/dev-tools/propeller.rst b/Documentation/dev-tools/propeller.rst new file mode 100644 index 000000000000..92195958e3db --- /dev/null +++ b/Documentation/dev-tools/propeller.rst @@ -0,0 +1,162 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +Using Propeller with the Linux kernel +===================================== + +This enables Propeller build support for the kernel when using Clang +compiler. Propeller is a profile-guided optimization (PGO) method used +to optimize binary executables. Like AutoFDO, it utilizes hardware +sampling to gather information about the frequency of execution of +different code paths within a binary. Unlike AutoFDO, this information +is then used right before linking phase to optimize (among others) +block layout within and across functions. + +A few important notes about adopting Propeller optimization: + +#. Although it can be used as a standalone optimization step, it is + strongly recommended to apply Propeller on top of AutoFDO, + AutoFDO+ThinLTO or Instrument FDO. The rest of this document + assumes this paradigm. + +#. Propeller uses another round of profiling on top of + AutoFDO/AutoFDO+ThinLTO/iFDO. The whole build process involves + "build-afdo - train-afdo - build-propeller - train-propeller - + build-optimized". + +#. Propeller requires LLVM 19 release or later for Clang/Clang++ + and the linker(ld.lld). + +#. In addition to LLVM toolchain, Propeller requires a profiling + conversion tool: https://github.com/google/autofdo with a release + after v0.30.1: https://github.com/google/autofdo/releases/tag/v0.30.1. + +The Propeller optimization process involves the following steps: + +#. Initial building: Build the AutoFDO or AutoFDO+ThinLTO binary as + you would normally do, but with a set of compile-time / link-time + flags, so that a special metadata section is created within the + kernel binary. The special section is only intend to be used by the + profiling tool, it is not part of the runtime image, nor does it + change kernel run time text sections. + +#. Profiling: The above kernel is then run with a representative + workload to gather execution frequency data. This data is collected + using hardware sampling, via perf. Propeller is most effective on + platforms supporting advanced PMU features like LBR on Intel + machines. This step is the same as profiling the kernel for AutoFDO + (the exact perf parameters can be different). + +#. Propeller profile generation: Perf output file is converted to a + pair of Propeller profiles via an offline tool. + +#. Optimized build: Build the AutoFDO or AutoFDO+ThinLTO optimized + binary as you would normally do, but with a compile-time / + link-time flag to pick up the Propeller compile time and link time + profiles. This build step uses 3 profiles - the AutoFDO profile, + the Propeller compile-time profile and the Propeller link-time + profile. + +#. Deployment: The optimized kernel binary is deployed and used + in production environments, providing improved performance + and reduced latency. + +Preparation +=========== + +Configure the kernel with:: + + CONFIG_AUTOFDO_CLANG=y + CONFIG_PROPELLER_CLANG=y + +Customization +============= + +The default CONFIG_PROPELLER_CLANG setting covers kernel space objects +for Propeller builds. One can, however, enable or disable Propeller build +for individual files and directories by adding a line similar to the +following to the respective kernel Makefile: + +- For enabling a single file (e.g. foo.o):: + + PROPELLER_PROFILE_foo.o := y + +- For enabling all files in one directory:: + + PROPELLER_PROFILE := y + +- For disabling one file:: + + PROPELLER_PROFILE_foo.o := n + +- For disabling all files in one directory:: + + PROPELLER__PROFILE := n + + +Workflow +======== + +Here is an example workflow for building an AutoFDO+Propeller kernel: + +1) Assuming an AutoFDO profile is already collected following + instructions in the AutoFDO document, build the kernel on the host + machine, with AutoFDO and Propeller build configs :: + + CONFIG_AUTOFDO_CLANG=y + CONFIG_PROPELLER_CLANG=y + + and :: + + $ make LLVM=1 CLANG_AUTOFDO_PROFILE= + +2) Install the kernel on the test machine. + +3) Run the load tests. The '-c' option in perf specifies the sample + event period. We suggest using a suitable prime number, like 500009, + for this purpose. + + - For Intel platforms:: + + $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c -o -- + + - For AMD platforms:: + + $ perf record --pfm-event RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a -N -b -c -o -- + + Note you can repeat the above steps to collect multiple s. + +4) (Optional) Download the raw perf file(s) to the host machine. + +5) Use the create_llvm_prof tool (https://github.com/google/autofdo) to + generate Propeller profile. :: + + $ create_llvm_prof --binary= --profile= + --format=propeller --propeller_output_module_name + --out=_cc_profile.txt + --propeller_symorder=_ld_profile.txt + + "" can be something like "/home/user/dir/any_string". + + This command generates a pair of Propeller profiles: + "_cc_profile.txt" and + "_ld_profile.txt". + + If there are more than 1 perf_file collected in the previous step, + you can create a temp list file "" with each line + containing one perf file name and run:: + + $ create_llvm_prof --binary= --profile=@ + --format=propeller --propeller_output_module_name + --out=_cc_profile.txt + --propeller_symorder=_ld_profile.txt + +6) Rebuild the kernel using the AutoFDO and Propeller + profiles. :: + + CONFIG_AUTOFDO_CLANG=y + CONFIG_PROPELLER_CLANG=y + + and :: + + $ make LLVM=1 CLANG_AUTOFDO_PROFILE= CLANG_PROPELLER_PROFILE_PREFIX= diff --git a/MAINTAINERS b/MAINTAINERS index 1eba172ed532..b422561537a3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18503,6 +18503,13 @@ S: Maintained F: include/linux/psi* F: kernel/sched/psi.c +PROPELLER BUILD +M: Rong Xu +M: Han Shen +S: Supported +F: Documentation/dev-tools/propeller.rst +F: scripts/Makefile.propeller + PRINTK M: Petr Mladek R: Steven Rostedt diff --git a/Makefile b/Makefile index 1f31c633a41d..8dceb6830486 100644 --- a/Makefile +++ b/Makefile @@ -1024,6 +1024,7 @@ include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan include-$(CONFIG_KCOV) += scripts/Makefile.kcov include-$(CONFIG_RANDSTRUCT) += scripts/Makefile.randstruct include-$(CONFIG_AUTOFDO_CLANG) += scripts/Makefile.autofdo +include-$(CONFIG_PROPELLER_CLANG) += scripts/Makefile.propeller include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins include $(addprefix $(srctree)/, $(include-y)) diff --git a/arch/Kconfig b/arch/Kconfig index 8dca3b5e6ef5..00551f340dbe 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -831,6 +831,25 @@ config AUTOFDO_CLANG If unsure, say N. +config ARCH_SUPPORTS_PROPELLER_CLANG + bool + +config PROPELLER_CLANG + bool "Enable Clang's Propeller build" + depends on ARCH_SUPPORTS_PROPELLER_CLANG + depends on CC_IS_CLANG && CLANG_VERSION >= 190000 + help + This option enables Clang’s Propeller build. When the Propeller + profiles is specified in variable CLANG_PROPELLER_PROFILE_PREFIX + during the build process, Clang uses the profiles to optimize + the kernel. + + If no profile is specified, Propeller options are still passed + to Clang to facilitate the collection of perf data for creating + the Propeller profiles in subsequent builds. + + If unsure, say N. + config ARCH_SUPPORTS_CFI_CLANG bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9dc87661fb37..89b8fc452a7c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -127,6 +127,7 @@ config X86 select ARCH_SUPPORTS_LTO_CLANG_THIN select ARCH_SUPPORTS_RT select ARCH_SUPPORTS_AUTOFDO_CLANG + select ARCH_SUPPORTS_PROPELLER_CLANG if X86_64 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if X86_CMPXCHG64 select ARCH_USE_MEMTEST diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index b8c5741d2fb4..cf22081601ed 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -443,6 +443,10 @@ SECTIONS STABS_DEBUG DWARF_DEBUG +#ifdef CONFIG_PROPELLER_CLANG + .llvm_bb_addr_map : { *(.llvm_bb_addr_map) } +#endif + ELF_DETAILS DISCARDS diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 8a0bb3946cf0..c995474e4c64 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -95,14 +95,14 @@ * With LTO_CLANG, the linker also splits sections by default, so we need * these macros to combine the sections during the final link. * - * With AUTOFDO_CLANG, by default, the linker splits text sections and - * regroups functions into subsections. + * With AUTOFDO_CLANG and PROPELLER_CLANG, by default, the linker splits + * text sections and regroups functions into subsections. * * RODATA_MAIN is not used because existing code already defines .rodata.x * sections to be brought in with rodata. */ #if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CLANG) || \ -defined(CONFIG_AUTOFDO_CLANG) +defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG) #define TEXT_MAIN .text .text.[0-9a-zA-Z_]* #else #define TEXT_MAIN .text diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 2d0942c1a027..e7859ad90224 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -201,6 +201,16 @@ _c_flags += $(if $(patsubst n%,, \ $(CFLAGS_AUTOFDO_CLANG)) endif +# +# Enable Propeller build flags except some files or directories we don't want to +# enable (depends on variables AUTOFDO_PROPELLER_obj.o and PROPELLER_PROFILE). +# +ifdef CONFIG_PROPELLER_CLANG +_c_flags += $(if $(patsubst n%,, \ + $(AUTOFDO_PROFILE_$(target-stem).o)$(AUTOFDO_PROFILE)$(PROPELLER_PROFILE))$(is-kernel-object), \ + $(CFLAGS_PROPELLER_CLANG)) +endif + # $(src) for including checkin headers from generated source files # $(obj) for including generated headers from checkin source files ifeq ($(KBUILD_EXTMOD),) diff --git a/scripts/Makefile.propeller b/scripts/Makefile.propeller new file mode 100644 index 000000000000..344190717e47 --- /dev/null +++ b/scripts/Makefile.propeller @@ -0,0 +1,28 @@ +# SPDX-License-Identifier: GPL-2.0 + +# Enable available and selected Clang Propeller features. +ifdef CLANG_PROPELLER_PROFILE_PREFIX + CFLAGS_PROPELLER_CLANG := -fbasic-block-sections=list=$(CLANG_PROPELLER_PROFILE_PREFIX)_cc_profile.txt -ffunction-sections + KBUILD_LDFLAGS += --symbol-ordering-file=$(CLANG_PROPELLER_PROFILE_PREFIX)_ld_profile.txt --no-warn-symbol-ordering +else + CFLAGS_PROPELLER_CLANG := -fbasic-block-sections=labels +endif + +# Propeller requires debug information to embed module names in the profiles. +# If CONFIG_DEBUG_INFO is not enabled, set -gmlt option. Skip this for AutoFDO, +# as the option should already be set. +ifndef CONFIG_DEBUG_INFO + ifndef CONFIG_AUTOFDO_CLANG + CFLAGS_PROPELLER_CLANG += -gmlt + endif +endif + +ifdef CONFIG_LTO_CLANG_THIN + ifdef CLANG_PROPELLER_PROFILE_PREFIX + KBUILD_LDFLAGS += --lto-basic-block-sections=$(CLANG_PROPELLER_PROFILE_PREFIX)_cc_profile.txt + else + KBUILD_LDFLAGS += --lto-basic-block-sections=labels + endif +endif + +export CFLAGS_PROPELLER_CLANG diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4c5229991e1e..05a0fb4a3d1a 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4558,6 +4558,7 @@ static int validate_ibt(struct objtool_file *file) !strcmp(sec->name, "__mcount_loc") || !strcmp(sec->name, ".kcfi_traps") || !strcmp(sec->name, ".llvm.call-graph-profile") || + !strcmp(sec->name, ".llvm_bb_addr_map") || strstr(sec->name, "__patchable_function_entries")) continue; -- cgit v1.2.3 From 0afd73c5f5c606b0f8f8ff036e4f5d6c4b788d02 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:29 +0900 Subject: kbuild: replace two $(abs_objtree) with $(CURDIR) in top Makefile Kbuild changes the working directory until it matches $(abs_objtree). When $(need-sub-make) is empty, $(abs_objtree) is the same as $(CURDIR). Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 8dceb6830486..891d28e54791 100644 --- a/Makefile +++ b/Makefile @@ -228,12 +228,12 @@ else # need-sub-make # We process the rest of the Makefile if this is the final invocation of make -ifeq ($(abs_srctree),$(abs_objtree)) +ifeq ($(abs_srctree),$(CURDIR)) # building in the source tree srctree := . building_out_of_srctree := else - ifeq ($(abs_srctree)/,$(dir $(abs_objtree))) + ifeq ($(abs_srctree)/,$(dir $(CURDIR))) # building in a subdirectory of the source tree srctree := .. else -- cgit v1.2.3 From 214c0eea43b2ea66bcd6467ea57e47ce8874191b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:30 +0900 Subject: kbuild: add $(objtree)/ prefix to some in-kernel build artifacts $(objtree) refers to the top of the output directory of kernel builds. This commit adds the explicit $(objtree)/ prefix to build artifacts needed for building external modules. This change has no immediate impact, as the top-level Makefile currently defines: objtree := . This commit prepares for supporting the building of external modules in a different directory. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 10 +++++----- arch/arm/Makefile | 4 ++-- arch/arm64/Makefile | 2 +- arch/powerpc/Makefile | 4 ++-- arch/riscv/Makefile | 2 +- scripts/Kbuild.include | 2 +- scripts/Makefile.build | 4 ++-- scripts/Makefile.modfinal | 14 +++++++------- scripts/Makefile.modinst | 2 +- scripts/Makefile.modpost | 12 ++++++------ scripts/depmod.sh | 4 ++-- 11 files changed, 30 insertions(+), 30 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 891d28e54791..9b8f4f4cb01b 100644 --- a/Makefile +++ b/Makefile @@ -354,7 +354,7 @@ else # !mixed-build include $(srctree)/scripts/Kbuild.include # Read KERNELRELEASE from include/config/kernel.release (if it exists) -KERNELRELEASE = $(call read-file, include/config/kernel.release) +KERNELRELEASE = $(call read-file, $(objtree)/include/config/kernel.release) KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION) export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION @@ -720,7 +720,7 @@ endif export KBUILD_MODULES KBUILD_BUILTIN ifdef need-config -include include/config/auto.conf +include $(objtree)/include/config/auto.conf endif ifeq ($(KBUILD_EXTMOD),) @@ -783,13 +783,13 @@ else # !may-sync-config # and include/config/auto.conf but do not care if they are up-to-date. # Use auto.conf to show the error message -checked-configs := include/generated/autoconf.h include/generated/rustc_cfg include/config/auto.conf +checked-configs := $(addprefix $(objtree)/, include/generated/autoconf.h include/generated/rustc_cfg include/config/auto.conf) missing-configs := $(filter-out $(wildcard $(checked-configs)), $(checked-configs)) ifdef missing-configs -PHONY += include/config/auto.conf +PHONY += $(objtree)/include/config/auto.conf -include/config/auto.conf: +$(objtree)/include/config/auto.conf: @echo >&2 '***' @echo >&2 '*** ERROR: Kernel configuration is invalid. The following files are missing:' @printf >&2 '*** - %s\n' $(missing-configs) diff --git a/arch/arm/Makefile b/arch/arm/Makefile index aafebf145738..00ca7886b18e 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -264,13 +264,13 @@ stack_protector_prepare: prepare0 -mstack-protector-guard=tls \ -mstack-protector-guard-offset=$(shell \ awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}'\ - include/generated/asm-offsets.h)) + $(objtree)/include/generated/asm-offsets.h)) else stack_protector_prepare: prepare0 $(eval SSP_PLUGIN_CFLAGS := \ -fplugin-arg-arm_ssp_per_task_plugin-offset=$(shell \ awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}'\ - include/generated/asm-offsets.h)) + $(objtree)/include/generated/asm-offsets.h)) $(eval KBUILD_CFLAGS += $(SSP_PLUGIN_CFLAGS)) $(eval GCC_PLUGINS_CFLAGS += $(SSP_PLUGIN_CFLAGS)) endif diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 9efd3f37c2fd..358c68565bfd 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -71,7 +71,7 @@ stack_protector_prepare: prepare0 -mstack-protector-guard-reg=sp_el0 \ -mstack-protector-guard-offset=$(shell \ awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}' \ - include/generated/asm-offsets.h)) + $(objtree)/include/generated/asm-offsets.h)) endif ifeq ($(CONFIG_ARM64_BTI_KERNEL),y) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index bbfe4a1f06ef..321b596d2550 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -402,9 +402,9 @@ prepare: stack_protector_prepare PHONY += stack_protector_prepare stack_protector_prepare: prepare0 ifdef CONFIG_PPC64 - $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "PACA_CANARY") print $$3;}' include/generated/asm-offsets.h)) + $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "PACA_CANARY") print $$3;}' $(objtree)/include/generated/asm-offsets.h)) else - $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "TASK_CANARY") print $$3;}' include/generated/asm-offsets.h)) + $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "TASK_CANARY") print $$3;}' $(objtree)/include/generated/asm-offsets.h)) endif endif diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index d469db9f46f4..a08cfeb6cbf9 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -129,7 +129,7 @@ stack_protector_prepare: prepare0 -mstack-protector-guard-reg=tp \ -mstack-protector-guard-offset=$(shell \ awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}' \ - include/generated/asm-offsets.h)) + $(objtree)/include/generated/asm-offsets.h)) endif # arch specific predefines for sparse diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index ed8a7493524b..8c311b997e24 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -205,7 +205,7 @@ if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:) cmd_and_fixdep = \ $(cmd); \ - scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\ + $(objtree)/scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\ rm -f $(depfile) # Usage: $(call if_changed_rule,foo) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 8f423a1faf50..dd7a80ebca62 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -34,7 +34,7 @@ subdir-asflags-y := subdir-ccflags-y := # Read auto.conf if it exists, otherwise ignore --include include/config/auto.conf +-include $(objtree)/include/config/auto.conf include $(srctree)/scripts/Kbuild.include include $(srctree)/scripts/Makefile.compiler @@ -107,7 +107,7 @@ cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< $(obj)/%.i: $(obj)/%.c FORCE $(call if_changed_dep,cpp_i_c) -genksyms = scripts/genksyms/genksyms \ +genksyms = $(objtree)/scripts/genksyms/genksyms \ $(if $(1), -T $(2)) \ $(if $(KBUILD_PRESERVE), -p) \ -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null) diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 1482884ec3ca..6d8aa3059ee2 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -6,7 +6,7 @@ PHONY := __modfinal __modfinal: -include include/config/auto.conf +include $(objtree)/include/config/auto.conf include $(srctree)/scripts/Kbuild.include # for c_flags @@ -37,15 +37,15 @@ quiet_cmd_ld_ko_o = LD [M] $@ cmd_ld_ko_o = \ $(LD) -r $(KBUILD_LDFLAGS) \ $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ - -T scripts/module.lds -o $@ $(filter %.o, $^) + -T $(objtree)/scripts/module.lds -o $@ $(filter %.o, $^) quiet_cmd_btf_ko = BTF [M] $@ cmd_btf_ko = \ - if [ ! -f vmlinux ]; then \ + if [ ! -f $(objtree)/vmlinux ]; then \ printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ else \ - LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) $(MODULE_PAHOLE_FLAGS) --btf_base vmlinux $@; \ - $(RESOLVE_BTFIDS) -b vmlinux $@; \ + LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) $(MODULE_PAHOLE_FLAGS) --btf_base $(objtree)/vmlinux $@; \ + $(RESOLVE_BTFIDS) -b $(objtree)/vmlinux $@; \ fi; # Same as newer-prereqs, but allows to exclude specified extra dependencies @@ -57,8 +57,8 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \ printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:) # Re-generate module BTFs if either module's .ko or vmlinux changed -%.ko: %.o %.mod.o $(extmod_prefix).module-common.o scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),vmlinux) FORCE - +$(call if_changed_except,ld_ko_o,vmlinux) +%.ko: %.o %.mod.o $(extmod_prefix).module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/vmlinux) FORCE + +$(call if_changed_except,ld_ko_o,$(objtree)/vmlinux) ifdef CONFIG_DEBUG_INFO_BTF_MODULES +$(if $(newer-prereqs),$(call cmd,btf_ko)) endif diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst index d97720943189..6fa9af4a25b4 100644 --- a/scripts/Makefile.modinst +++ b/scripts/Makefile.modinst @@ -6,7 +6,7 @@ PHONY := __modinst __modinst: -include include/config/auto.conf +include $(objtree)/include/config/auto.conf include $(srctree)/scripts/Kbuild.include install-y := diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 44936ebad161..12e7c15d099c 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -35,10 +35,10 @@ PHONY := __modpost __modpost: -include include/config/auto.conf +include $(objtree)/include/config/auto.conf include $(srctree)/scripts/Kbuild.include -MODPOST = scripts/mod/modpost +MODPOST = $(objtree)/scripts/mod/modpost modpost-args = \ $(if $(CONFIG_MODULES),-M) \ @@ -119,11 +119,11 @@ include $(kbuild-file) output-symdump := $(KBUILD_EXTMOD)/Module.symvers -ifeq ($(wildcard Module.symvers),) -missing-input := Module.symvers +ifeq ($(wildcard $(objtree)/Module.symvers),) +missing-input := $(objtree)/Module.symvers else -modpost-args += -i Module.symvers -modpost-deps += Module.symvers +modpost-args += -i $(objtree)/Module.symvers +modpost-deps += $(objtree)/Module.symvers endif modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS)) diff --git a/scripts/depmod.sh b/scripts/depmod.sh index e22da27fe13e..3c34fecacbc8 100755 --- a/scripts/depmod.sh +++ b/scripts/depmod.sh @@ -12,7 +12,7 @@ KERNELRELEASE=$1 : ${DEPMOD:=depmod} -if ! test -r System.map ; then +if ! test -r "${objtree}/System.map" ; then echo "Warning: modules_install: missing 'System.map' file. Skipping depmod." >&2 exit 0 fi @@ -25,7 +25,7 @@ if [ -z $(command -v $DEPMOD) ]; then exit 0 fi -set -- -ae -F System.map +set -- -ae -F "${objtree}/System.map" if test -n "$INSTALL_MOD_PATH"; then set -- "$@" -b "$INSTALL_MOD_PATH" fi -- cgit v1.2.3 From 5ea172165400e6efaa88989c837d2077c49161d8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:31 +0900 Subject: kbuild: rename abs_objtree to abs_output 'objtree' refers to the top of the output directory of kernel builds. Rename abs_objtree to a more generic name, to better reflect its use in the context of external module builds. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 9b8f4f4cb01b..deb3f01863f8 100644 --- a/Makefile +++ b/Makefile @@ -40,7 +40,7 @@ __all: this-makefile := $(lastword $(MAKEFILE_LIST)) abs_srctree := $(realpath $(dir $(this-makefile))) -abs_objtree := $(CURDIR) +abs_output := $(CURDIR) ifneq ($(sub_make_done),1) @@ -185,8 +185,8 @@ ifneq ($(KBUILD_OUTPUT),) # $(realpath ...) gets empty if the path does not exist. Run 'mkdir -p' first. $(shell mkdir -p "$(KBUILD_OUTPUT)") # $(realpath ...) resolves symlinks -abs_objtree := $(realpath $(KBUILD_OUTPUT)) -$(if $(abs_objtree),,$(error failed to create output directory "$(KBUILD_OUTPUT)")) +abs_output := $(realpath $(KBUILD_OUTPUT)) +$(if $(abs_output),,$(error failed to create output directory "$(KBUILD_OUTPUT)")) endif # ifneq ($(KBUILD_OUTPUT),) ifneq ($(words $(subst :, ,$(abs_srctree))), 1) @@ -197,7 +197,7 @@ export sub_make_done := 1 endif # sub_make_done -ifeq ($(abs_objtree),$(CURDIR)) +ifeq ($(abs_output),$(CURDIR)) # Suppress "Entering directory ..." if we are at the final work directory. no-print-directory := --no-print-directory else @@ -221,7 +221,7 @@ $(filter-out $(this-makefile), $(MAKECMDGOALS)) __all: __sub-make # Invoke a second make in the output directory, passing relevant variables __sub-make: - $(Q)$(MAKE) $(no-print-directory) -C $(abs_objtree) \ + $(Q)$(MAKE) $(no-print-directory) -C $(abs_output) \ -f $(abs_srctree)/Makefile $(MAKECMDGOALS) else # need-sub-make -- cgit v1.2.3 From d17113601909eb43c29cbb3449fd49db427ff6be Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:32 +0900 Subject: kbuild: use 'output' variable to create the output directory $(KBUILD_OUTPUT) specifies the output directory of kernel builds. Use a more generic name, 'output', to better reflect this code hunk in the context of external module builds. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index deb3f01863f8..cf1d55560ae2 100644 --- a/Makefile +++ b/Makefile @@ -176,18 +176,20 @@ export KBUILD_EXTRA_WARN # The O= assignment takes precedence over the KBUILD_OUTPUT environment # variable. -# Do we want to change the working directory? ifeq ("$(origin O)", "command line") KBUILD_OUTPUT := $(O) endif -ifneq ($(KBUILD_OUTPUT),) +output := $(KBUILD_OUTPUT) + +# Do we want to change the working directory? +ifneq ($(output),) # $(realpath ...) gets empty if the path does not exist. Run 'mkdir -p' first. -$(shell mkdir -p "$(KBUILD_OUTPUT)") +$(shell mkdir -p "$(output)") # $(realpath ...) resolves symlinks -abs_output := $(realpath $(KBUILD_OUTPUT)) -$(if $(abs_output),,$(error failed to create output directory "$(KBUILD_OUTPUT)")) -endif # ifneq ($(KBUILD_OUTPUT),) +abs_output := $(realpath $(output)) +$(if $(abs_output),,$(error failed to create output directory "$(output)")) +endif ifneq ($(words $(subst :, ,$(abs_srctree))), 1) $(error source directory cannot contain spaces or colons) -- cgit v1.2.3 From 13b25489b6f8bd73ed65f07928f7c27a481f1820 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:33 +0900 Subject: kbuild: change working directory to external module directory with M= Currently, Kbuild always operates in the output directory of the kernel, even when building external modules. This increases the risk of external module Makefiles attempting to write to the kernel directory. This commit switches the working directory to the external module directory, allowing the removal of the $(KBUILD_EXTMOD)/ prefix from some build artifacts. The command for building external modules maintains backward compatibility, but Makefiles that rely on working in the kernel directory may break. In such cases, $(objtree) and $(srctree) should be used to refer to the output and source directories of the kernel. The appearance of the build log will change as follows: [Before] $ make -C /path/to/my/linux M=/path/to/my/externel/module make: Entering directory '/path/to/my/linux' CC [M] /path/to/my/externel/module/helloworld.o MODPOST /path/to/my/externel/module/Module.symvers CC [M] /path/to/my/externel/module/helloworld.mod.o CC [M] /path/to/my/externel/module/.module-common.o LD [M] /path/to/my/externel/module/helloworld.ko make: Leaving directory '/path/to/my/linux' [After] $ make -C /path/to/my/linux M=/path/to/my/externel/module make: Entering directory '/path/to/my/linux' make[1]: Entering directory '/path/to/my/externel/module' CC [M] helloworld.o MODPOST Module.symvers CC [M] helloworld.mod.o CC [M] .module-common.o LD [M] helloworld.ko make[1]: Leaving directory '/path/to/my/externel/module' make: Leaving directory '/path/to/my/linux' Printing "Entering directory" twice is cumbersome. This will be addressed later. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Documentation/dev-tools/coccinelle.rst | 22 +++------ Documentation/kbuild/makefiles.rst | 14 ++++++ Makefile | 82 ++++++++++++++++++++-------------- rust/Makefile | 4 +- scripts/Makefile.build | 2 +- scripts/Makefile.clean | 2 +- scripts/Makefile.compiler | 2 +- scripts/Makefile.modpost | 6 +-- scripts/coccicheck | 6 +-- scripts/nsdeps | 8 +--- scripts/package/install-extmod-build | 7 +++ 11 files changed, 87 insertions(+), 68 deletions(-) (limited to 'Makefile') diff --git a/Documentation/dev-tools/coccinelle.rst b/Documentation/dev-tools/coccinelle.rst index 535ce126fb4f..6e70a1e9a3c0 100644 --- a/Documentation/dev-tools/coccinelle.rst +++ b/Documentation/dev-tools/coccinelle.rst @@ -250,25 +250,17 @@ variables for .cocciconfig is as follows: - Your directory from which spatch is called is processed next - The directory provided with the ``--dir`` option is processed last, if used -Since coccicheck runs through make, it naturally runs from the kernel -proper dir; as such the second rule above would be implied for picking up a -.cocciconfig when using ``make coccicheck``. - ``make coccicheck`` also supports using M= targets. If you do not supply any M= target, it is assumed you want to target the entire kernel. The kernel coccicheck script has:: - if [ "$KBUILD_EXTMOD" = "" ] ; then - OPTIONS="--dir $srctree $COCCIINCLUDE" - else - OPTIONS="--dir $KBUILD_EXTMOD $COCCIINCLUDE" - fi - -KBUILD_EXTMOD is set when an explicit target with M= is used. For both cases -the spatch ``--dir`` argument is used, as such third rule applies when whether -M= is used or not, and when M= is used the target directory can have its own -.cocciconfig file. When M= is not passed as an argument to coccicheck the -target directory is the same as the directory from where spatch was called. + OPTIONS="--dir $srcroot $COCCIINCLUDE" + +Here, $srcroot refers to the source directory of the target: it points to the +external module's source directory when M= used, and otherwise, to the kernel +source directory. The third rule ensures the spatch reads the .cocciconfig from +the target directory, allowing external modules to have their own .cocciconfig +file. If not using the kernel's coccicheck target, keep the above precedence order logic of .cocciconfig reading. If using the kernel's coccicheck target, diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst index 7964e0c245ae..d36519f194dc 100644 --- a/Documentation/kbuild/makefiles.rst +++ b/Documentation/kbuild/makefiles.rst @@ -449,6 +449,20 @@ $(obj) to prerequisites are referenced with $(src) (because they are not generated files). +$(srcroot) + $(srcroot) refers to the root of the source you are building, which can be + either the kernel source or the external modules source, depending on whether + KBUILD_EXTMOD is set. This can be either a relative or an absolute path, but + if KBUILD_ABS_SRCTREE=1 is set, it is always an absolute path. + +$(srctree) + $(srctree) refers to the root of the kernel source tree. When building the + kernel, this is the same as $(srcroot). + +$(objtree) + $(objtree) refers to the root of the kernel object tree. It is ``.`` when + building the kernel, but it is different when building external modules. + $(kecho) echoing information to user in a rule is often a good practice but when execution ``make -s`` one does not expect to see any output diff --git a/Makefile b/Makefile index cf1d55560ae2..2718d2037f5e 100644 --- a/Makefile +++ b/Makefile @@ -180,7 +180,24 @@ ifeq ("$(origin O)", "command line") KBUILD_OUTPUT := $(O) endif -output := $(KBUILD_OUTPUT) +ifdef KBUILD_EXTMOD + ifdef KBUILD_OUTPUT + objtree := $(realpath $(KBUILD_OUTPUT)) + $(if $(objtree),,$(error specified kernel directory "$(KBUILD_OUTPUT)" does not exist)) + else + objtree := $(CURDIR) + endif + output := $(KBUILD_EXTMOD) + # KBUILD_EXTMOD might be a relative path. Remember its absolute path before + # Make changes the working directory. + srcroot := $(realpath $(KBUILD_EXTMOD)) + $(if $(srcroot),,$(error specified external module directory "$(KBUILD_EXTMOD)" does not exist)) +else + objtree := . + output := $(KBUILD_OUTPUT) +endif + +export objtree srcroot # Do we want to change the working directory? ifneq ($(output),) @@ -230,36 +247,34 @@ else # need-sub-make # We process the rest of the Makefile if this is the final invocation of make -ifeq ($(abs_srctree),$(CURDIR)) - # building in the source tree - srctree := . - building_out_of_srctree := -else - ifeq ($(abs_srctree)/,$(dir $(CURDIR))) - # building in a subdirectory of the source tree - srctree := .. - else - srctree := $(abs_srctree) - endif - building_out_of_srctree := 1 +ifndef KBUILD_EXTMOD +srcroot := $(abs_srctree) endif -ifneq ($(KBUILD_ABS_SRCTREE),) -srctree := $(abs_srctree) +ifeq ($(srcroot),$(CURDIR)) +building_out_of_srctree := +else +export building_out_of_srctree := 1 endif -objtree := . +ifdef KBUILD_ABS_SRCTREE + # Do nothing. Use the absolute path. +else ifeq ($(srcroot),$(CURDIR)) + # Building in the source. + srcroot := . +else ifeq ($(srcroot)/,$(dir $(CURDIR))) + # Building in a subdirectory of the source. + srcroot := .. +endif -VPATH := +export srctree := $(if $(KBUILD_EXTMOD),$(abs_srctree),$(srcroot)) -ifeq ($(KBUILD_EXTMOD),) ifdef building_out_of_srctree -VPATH := $(srctree) -endif +export VPATH := $(srcroot) +else +VPATH := endif -export building_out_of_srctree srctree objtree VPATH - # To make sure we do not include .config for any of the *config targets # catch them early, and hand them over to scripts/kconfig/Makefile # It is allowed to specify more targets when calling make, including @@ -540,7 +555,7 @@ USERINCLUDE := \ LINUXINCLUDE := \ -I$(srctree)/arch/$(SRCARCH)/include \ -I$(objtree)/arch/$(SRCARCH)/include/generated \ - $(if $(building_out_of_srctree),-I$(srctree)/include) \ + -I$(srctree)/include \ -I$(objtree)/include \ $(USERINCLUDE) @@ -711,7 +726,7 @@ endif # in addition to whatever we do anyway. # Just "make" or "make all" shall build modules as well -ifneq ($(filter all modules nsdeps %compile_commands.json clang-%,$(MAKECMDGOALS)),) +ifneq ($(filter all modules nsdeps compile_commands.json clang-%,$(MAKECMDGOALS)),) KBUILD_MODULES := 1 endif @@ -1107,7 +1122,7 @@ export MODLIB PHONY += prepare0 -export extmod_prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/) +export extmod_prefix = export MODORDER := $(extmod_prefix)modules.order export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps @@ -1799,14 +1814,10 @@ filechk_kernel.release = echo $(KERNELRELEASE) KBUILD_BUILTIN := KBUILD_MODULES := 1 -build-dir := $(KBUILD_EXTMOD) +build-dir := . -compile_commands.json: $(extmod_prefix)compile_commands.json -PHONY += compile_commands.json - -clean-dirs := $(KBUILD_EXTMOD) -clean: private rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \ - $(KBUILD_EXTMOD)/compile_commands.json +clean-dirs := . +clean: private rm-files := Module.symvers modules.nsdeps compile_commands.json PHONY += prepare # now expand this into a simple variable to reduce the cost of shell evaluations @@ -1948,7 +1959,7 @@ $(clean-dirs): clean: $(clean-dirs) $(call cmd,rmfiles) - @find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \ + @find . $(RCS_FIND_IGNORE) \ \( -name '*.[aios]' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \ -o -name '*.ko.*' \ -o -name '*.dtb' -o -name '*.dtbo' \ @@ -1981,7 +1992,12 @@ tags TAGS cscope gtags: FORCE PHONY += rust-analyzer rust-analyzer: +$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh +ifdef KBUILD_EXTMOD +# FIXME: external modules must not descend into a sub-directory of the kernel + $(Q)$(MAKE) $(build)=$(objtree)/rust src=$(srctree)/rust $@ +else $(Q)$(MAKE) $(build)=rust $@ +endif # Script to generate missing namespace dependencies # --------------------------------------------------------------------------- diff --git a/rust/Makefile b/rust/Makefile index b5e0a73b78f3..742740816c4b 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -362,8 +362,8 @@ rust-analyzer: $(Q)$(srctree)/scripts/generate_rust_analyzer.py \ --cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \ $(realpath $(srctree)) $(realpath $(objtree)) \ - $(rustc_sysroot) $(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \ - $(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json + $(rustc_sysroot) $(RUST_LIB_SRC) $(if $(KBUILD_EXTMOD),$(srcroot)) \ + > rust-project.json redirect-intrinsics = \ __addsf3 __eqsf2 __extendsfdf2 __gesf2 __lesf2 __ltsf2 __mulsf3 __nesf2 __truncdfsf2 __unordsf2 \ diff --git a/scripts/Makefile.build b/scripts/Makefile.build index dd7a80ebca62..e5e382a1d64d 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -3,7 +3,7 @@ # Building # ========================================================================== -src := $(if $(VPATH),$(VPATH)/)$(obj) +src := $(srcroot)/$(obj) PHONY := $(obj)/ $(obj)/: diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean index 4fcfab40ed61..6ead00ec7313 100644 --- a/scripts/Makefile.clean +++ b/scripts/Makefile.clean @@ -3,7 +3,7 @@ # Cleaning up # ========================================================================== -src := $(if $(VPATH),$(VPATH)/)$(obj) +src := $(srcroot)/$(obj) PHONY := __clean __clean: diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler index e0842496d26e..8c1029687e2e 100644 --- a/scripts/Makefile.compiler +++ b/scripts/Makefile.compiler @@ -13,7 +13,7 @@ cc-cross-prefix = $(firstword $(foreach c, $(1), \ $(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c)))) # output directory for tests below -TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$ +TMPOUT = .tmp_$$$$ # try-run # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise) diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 12e7c15d099c..78d2ca4f25f5 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -111,13 +111,13 @@ endif else # set src + obj - they may be used in the modules's Makefile -obj := $(KBUILD_EXTMOD) -src := $(if $(VPATH),$(VPATH)/)$(obj) +obj := . +src := $(srcroot) # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS include $(kbuild-file) -output-symdump := $(KBUILD_EXTMOD)/Module.symvers +output-symdump := Module.symvers ifeq ($(wildcard $(objtree)/Module.symvers),) missing-input := $(objtree)/Module.symvers diff --git a/scripts/coccicheck b/scripts/coccicheck index e52cb43fede6..0e6bc5a10320 100755 --- a/scripts/coccicheck +++ b/scripts/coccicheck @@ -80,11 +80,7 @@ command results in a shift count error.' NPROC=1 else ONLINE=0 - if [ "$KBUILD_EXTMOD" = "" ] ; then - OPTIONS="--dir $srctree $COCCIINCLUDE" - else - OPTIONS="--dir $KBUILD_EXTMOD $COCCIINCLUDE" - fi + OPTIONS="--dir $srcroot $COCCIINCLUDE" # Use only one thread per core by default if hyperthreading is enabled THREADS_PER_CORE=$(LANG=C lscpu | grep "Thread(s) per core: " | tr -cd "[:digit:]") diff --git a/scripts/nsdeps b/scripts/nsdeps index f1718cc0d700..8ca12e2b5c03 100644 --- a/scripts/nsdeps +++ b/scripts/nsdeps @@ -19,12 +19,6 @@ if ! { echo "$SPATCH_REQ_VERSION"; echo "$SPATCH_VERSION"; } | sort -CV ; then exit 1 fi -if [ "$KBUILD_EXTMOD" ]; then - src_prefix= -else - src_prefix=$srctree/ -fi - generate_deps_for_ns() { $SPATCH --very-quiet --in-place --sp-file \ $srctree/scripts/coccinelle/misc/add_namespace.cocci -D nsdeps -D ns=$1 $2 @@ -34,7 +28,7 @@ generate_deps() { local mod=${1%.ko:} shift local namespaces="$*" - local mod_source_files=$(sed "s|^\(.*\)\.o$|${src_prefix}\1.c|" $mod.mod) + local mod_source_files=$(sed "s|^\(.*\)\.o$|${srcroot}/\1.c|" $mod.mod) for ns in $namespaces; do echo "Adding namespace $ns to module $mod.ko." diff --git a/scripts/package/install-extmod-build b/scripts/package/install-extmod-build index 7ec1f061a519..64d958ee45f3 100755 --- a/scripts/package/install-extmod-build +++ b/scripts/package/install-extmod-build @@ -51,6 +51,13 @@ mkdir -p "${destdir}" if [ "${CC}" != "${HOSTCC}" ]; then echo "Rebuilding host programs with ${CC}..." + # This leverages external module building. + # - Clear sub_make_done to allow the top-level Makefile to redo sub-make. + # - Filter out --no-print-directory to print "Entering directory" logs + # when Make changes the working directory. + unset sub_make_done + MAKEFLAGS=$(echo "${MAKEFLAGS}" | sed s/--no-print-directory//) + cat <<-'EOF' > "${destdir}/Kbuild" subdir-y := scripts EOF -- cgit v1.2.3 From bad6beb2c0bb982b830f592a7b3e3eee76cbb85a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:34 +0900 Subject: kbuild: remove extmod_prefix, MODORDER, MODULES_NSDEPS variables With the previous changes, $(extmod_prefix), $(MODORDER), and $(MODULES_NSDEPS) are constant. (empty, modules.order, and modules.nsdeps, respectively). Remove these variables and hard-code their values. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 22 +++++++++------------- scripts/Makefile.modfinal | 8 ++++---- scripts/Makefile.modinst | 6 +++--- scripts/Makefile.modpost | 6 +++--- scripts/nsdeps | 2 +- 5 files changed, 20 insertions(+), 24 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 2718d2037f5e..b82c84903c88 100644 --- a/Makefile +++ b/Makefile @@ -1122,10 +1122,6 @@ export MODLIB PHONY += prepare0 -export extmod_prefix = -export MODORDER := $(extmod_prefix)modules.order -export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps - ifeq ($(KBUILD_EXTMOD),) build-dir := . @@ -1876,7 +1872,7 @@ endif ifdef CONFIG_MODULES -$(MODORDER): $(build-dir) +modules.order: $(build-dir) @: # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. @@ -1887,7 +1883,7 @@ ifneq ($(KBUILD_MODPOST_NOFINAL),1) endif PHONY += modules_check -modules_check: $(MODORDER) +modules_check: modules.order $(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh $< else # CONFIG_MODULES @@ -1928,15 +1924,15 @@ $(single-ko): single_modules $(single-no-ko): $(build-dir) @: -# Remove MODORDER when done because it is not the real one. +# Remove modules.order when done because it is not the real one. PHONY += single_modules single_modules: $(single-no-ko) modules_prepare - $(Q){ $(foreach m, $(single-ko), echo $(extmod_prefix)$(m:%.ko=%.o);) } > $(MODORDER) + $(Q){ $(foreach m, $(single-ko), echo $(m:%.ko=%.o);) } > modules.order $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost ifneq ($(KBUILD_MODPOST_NOFINAL),1) $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal endif - $(Q)rm -f $(MODORDER) + $(Q)rm -f modules.order single-goals := $(addprefix $(build-dir)/, $(single-no-ko)) @@ -2013,12 +2009,12 @@ nsdeps: modules quiet_cmd_gen_compile_commands = GEN $@ cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs)) -$(extmod_prefix)compile_commands.json: $(srctree)/scripts/clang-tools/gen_compile_commands.py \ +compile_commands.json: $(srctree)/scripts/clang-tools/gen_compile_commands.py \ $(if $(KBUILD_EXTMOD),, vmlinux.a $(KBUILD_VMLINUX_LIBS)) \ - $(if $(CONFIG_MODULES), $(MODORDER)) FORCE + $(if $(CONFIG_MODULES), modules.order) FORCE $(call if_changed,gen_compile_commands) -targets += $(extmod_prefix)compile_commands.json +targets += compile_commands.json PHONY += clang-tidy clang-analyzer @@ -2026,7 +2022,7 @@ ifdef CONFIG_CC_IS_CLANG quiet_cmd_clang_tools = CHECK $< cmd_clang_tools = $(PYTHON3) $(srctree)/scripts/clang-tools/run-clang-tools.py $@ $< -clang-tidy clang-analyzer: $(extmod_prefix)compile_commands.json +clang-tidy clang-analyzer: compile_commands.json $(call cmd,clang_tools) else clang-tidy clang-analyzer: diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 6d8aa3059ee2..bab53884f7e3 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -13,7 +13,7 @@ include $(srctree)/scripts/Kbuild.include include $(srctree)/scripts/Makefile.lib # find all modules listed in modules.order -modules := $(call read-file, $(MODORDER)) +modules := $(call read-file, modules.order) __modfinal: $(modules:%.o=%.ko) @: @@ -30,7 +30,7 @@ quiet_cmd_cc_o_c = CC [M] $@ %.mod.o: %.mod.c FORCE $(call if_changed_dep,cc_o_c) -$(extmod_prefix).module-common.o: $(srctree)/scripts/module-common.c FORCE +.module-common.o: $(srctree)/scripts/module-common.c FORCE $(call if_changed_dep,cc_o_c) quiet_cmd_ld_ko_o = LD [M] $@ @@ -57,13 +57,13 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \ printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:) # Re-generate module BTFs if either module's .ko or vmlinux changed -%.ko: %.o %.mod.o $(extmod_prefix).module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/vmlinux) FORCE +%.ko: %.o %.mod.o .module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/vmlinux) FORCE +$(call if_changed_except,ld_ko_o,$(objtree)/vmlinux) ifdef CONFIG_DEBUG_INFO_BTF_MODULES +$(if $(newer-prereqs),$(call cmd,btf_ko)) endif -targets += $(modules:%.o=%.ko) $(modules:%.o=%.mod.o) $(extmod_prefix).module-common.o +targets += $(modules:%.o=%.ko) $(modules:%.o=%.mod.o) .module-common.o # Add FORCE to the prerequisites of a target to force it to be always rebuilt. # --------------------------------------------------------------------------- diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst index 6fa9af4a25b4..f97c9926ed31 100644 --- a/scripts/Makefile.modinst +++ b/scripts/Makefile.modinst @@ -40,7 +40,7 @@ $(addprefix $(MODLIB)/, modules.builtin modules.builtin.modinfo modules.builtin. endif -modules := $(call read-file, $(MODORDER)) +modules := $(call read-file, modules.order) ifeq ($(KBUILD_EXTMOD),) dst := $(MODLIB)/kernel @@ -59,7 +59,7 @@ suffix-$(CONFIG_MODULE_COMPRESS_XZ) := .xz suffix-$(CONFIG_MODULE_COMPRESS_ZSTD) := .zst endif -modules := $(patsubst $(extmod_prefix)%.o, $(dst)/%.ko$(suffix-y), $(modules)) +modules := $(patsubst %.o, $(dst)/%.ko$(suffix-y), $(modules)) install-$(CONFIG_MODULES) += $(modules) __modinst: $(install-y) @@ -119,7 +119,7 @@ endif # Create necessary directories $(foreach dir, $(sort $(dir $(install-y))), $(shell mkdir -p $(dir))) -$(dst)/%.ko: $(extmod_prefix)%.ko FORCE +$(dst)/%.ko: %.ko FORCE $(call cmd,install) $(call cmd,strip) $(call cmd,sign) diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 78d2ca4f25f5..ab0e94ea6249 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -46,7 +46,7 @@ modpost-args = \ $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ $(if $(KBUILD_MODPOST_WARN),-w) \ - $(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \ + $(if $(KBUILD_NSDEPS),-d modules.nsdeps) \ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) \ $(if $(findstring 1, $(KBUILD_EXTRA_WARN)),-W) \ -o $@ @@ -61,8 +61,8 @@ endif # Read out modules.order to pass in modpost. # Otherwise, allmodconfig would fail with "Argument list too long". ifdef KBUILD_MODULES -modpost-args += -T $(MODORDER) -modpost-deps += $(MODORDER) +modpost-args += -T modules.order +modpost-deps += modules.order endif ifeq ($(KBUILD_EXTMOD),) diff --git a/scripts/nsdeps b/scripts/nsdeps index 8ca12e2b5c03..bab4ec870e50 100644 --- a/scripts/nsdeps +++ b/scripts/nsdeps @@ -51,4 +51,4 @@ generate_deps() { while read line do generate_deps $line -done < $MODULES_NSDEPS +done < modules.nsdeps -- cgit v1.2.3 From 11b3d5175e6bc3779159228e6077be202d2b0069 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:35 +0900 Subject: kbuild: support building external modules in a separate build directory There has been a long-standing request to support building external modules in a separate build directory. This commit introduces a new environment variable, KBUILD_EXTMOD_OUTPUT, and its shorthand Make variable, MO. A simple usage: $ make -C M= MO= Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Documentation/kbuild/kbuild.rst | 8 +++++++- Documentation/kbuild/modules.rst | 8 +++++++- Makefile | 20 ++++++++++++++++++-- scripts/Makefile.host | 8 +++----- scripts/Makefile.lib | 2 -- 5 files changed, 35 insertions(+), 11 deletions(-) (limited to 'Makefile') diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst index 1796b3eba37b..17c9f920f03d 100644 --- a/Documentation/kbuild/kbuild.rst +++ b/Documentation/kbuild/kbuild.rst @@ -137,12 +137,18 @@ Specify the output directory when building the kernel. This variable can also be used to point to the kernel output directory when building external modules against a pre-built kernel in a separate build directory. Please note that this does NOT specify the output directory for the -external modules themselves. +external modules themselves. (Use KBUILD_EXTMOD_OUTPUT for that purpose.) The output directory can also be specified using "O=...". Setting "O=..." takes precedence over KBUILD_OUTPUT. +KBUILD_EXTMOD_OUTPUT +-------------------- +Specify the output directory for external modules. + +Setting "MO=..." takes precedence over KBUILD_EXTMOD_OUTPUT. + KBUILD_EXTRA_WARN ----------------- Specify the extra build checks. The same value can be assigned by passing diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst index cd5a54d91e6d..a01f3754c7fc 100644 --- a/Documentation/kbuild/modules.rst +++ b/Documentation/kbuild/modules.rst @@ -66,7 +66,10 @@ Options of the kernel output directory if the kernel was built in a separate build directory.) - make -C $KDIR M=$PWD + You can optionally pass MO= option if you want to build the modules in + a separate directory. + + make -C $KDIR M=$PWD [MO=$BUILD_DIR] -C $KDIR The directory that contains the kernel and relevant build @@ -80,6 +83,9 @@ Options directory where the external module (kbuild file) is located. + MO=$BUILD_DIR + Specifies a separate output directory for the external module. + Targets ------- diff --git a/Makefile b/Makefile index b82c84903c88..5aba1ac89375 100644 --- a/Makefile +++ b/Makefile @@ -134,6 +134,10 @@ ifeq ("$(origin M)", "command line") KBUILD_EXTMOD := $(M) endif +ifeq ("$(origin MO)", "command line") + KBUILD_EXTMOD_OUTPUT := $(MO) +endif + $(if $(word 2, $(KBUILD_EXTMOD)), \ $(error building multiple external modules is not supported)) @@ -187,7 +191,7 @@ ifdef KBUILD_EXTMOD else objtree := $(CURDIR) endif - output := $(KBUILD_EXTMOD) + output := $(or $(KBUILD_EXTMOD_OUTPUT),$(KBUILD_EXTMOD)) # KBUILD_EXTMOD might be a relative path. Remember its absolute path before # Make changes the working directory. srcroot := $(realpath $(KBUILD_EXTMOD)) @@ -645,6 +649,7 @@ quiet_cmd_makefile = GEN Makefile } > Makefile outputmakefile: +ifeq ($(KBUILD_EXTMOD),) @if [ -f $(srctree)/.config -o \ -d $(srctree)/include/config -o \ -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \ @@ -654,7 +659,16 @@ outputmakefile: echo >&2 "***"; \ false; \ fi - $(Q)ln -fsn $(srctree) source +else + @if [ -f $(srcroot)/modules.order ]; then \ + echo >&2 "***"; \ + echo >&2 "*** The external module source tree is not clean."; \ + echo >&2 "*** Please run 'make -C $(abs_srctree) M=$(realpath $(srcroot)) clean'"; \ + echo >&2 "***"; \ + false; \ + fi +endif + $(Q)ln -fsn $(srcroot) source $(call cmd,makefile) $(Q)test -e .gitignore || \ { echo "# this is build directory, ignore it"; echo "*"; } > .gitignore @@ -1940,6 +1954,8 @@ KBUILD_MODULES := 1 endif +prepare: outputmakefile + # Preset locale variables to speed up the build process. Limit locale # tweaks to this spot to avoid wrong language settings when running # make menuconfig etc. diff --git a/scripts/Makefile.host b/scripts/Makefile.host index e01c13a588dd..c1dedf646a39 100644 --- a/scripts/Makefile.host +++ b/scripts/Makefile.host @@ -96,12 +96,10 @@ hostrust_flags = --out-dir $(dir $@) --emit=dep-info=$(depfile) \ $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \ $(HOSTRUSTFLAGS_$(target-stem)) -# $(objtree)/$(obj) for including generated headers from checkin source files -ifeq ($(KBUILD_EXTMOD),) +# $(obj) for including generated headers from checkin source files ifdef building_out_of_srctree -hostc_flags += -I $(objtree)/$(obj) -hostcxx_flags += -I $(objtree)/$(obj) -endif +hostc_flags += -I $(obj) +hostcxx_flags += -I $(obj) endif ##### diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index e7859ad90224..5660dfc9ed36 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -213,13 +213,11 @@ endif # $(src) for including checkin headers from generated source files # $(obj) for including generated headers from checkin source files -ifeq ($(KBUILD_EXTMOD),) ifdef building_out_of_srctree _c_flags += $(addprefix -I, $(src) $(obj)) _a_flags += $(addprefix -I, $(src) $(obj)) _cpp_flags += $(addprefix -I, $(src) $(obj)) endif -endif # If $(is-kernel-object) is 'y', this object will be linked to vmlinux or modules is-kernel-object = $(or $(part-of-builtin),$(part-of-module)) -- cgit v1.2.3 From 1d3730f0012fa04ec392b52cc21f945704ac2e16 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:36 +0900 Subject: kbuild: support -fmacro-prefix-map for external modules This commit makes -fmacro-prefix-map work for external modules built in a separate output directory. It improves the reproducibility of external modules and provides the benefits described in commit a73619a845d5 ("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path"). When building_out_of_srctree is not defined (e.g., when the kernel or external module is built in the source directory), this option is unnecessary. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 5aba1ac89375..a4ac0133f7cd 100644 --- a/Makefile +++ b/Makefile @@ -1041,8 +1041,10 @@ ifdef CONFIG_CC_IS_GCC KBUILD_CFLAGS += -fconserve-stack endif -# change __FILE__ to the relative path from the srctree -KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) +# change __FILE__ to the relative path to the source directory +ifdef building_out_of_srctree +KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=) +endif # include additional Makefiles when needed include-y := scripts/Makefile.extrawarn -- cgit v1.2.3 From 822b11a74ba2bc79ddd4165d55e988514c053d71 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:37 +0900 Subject: kbuild: use absolute path in the generated wrapper Makefile Keep the consistent behavior when this Makefile is invoked from another directory. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index a4ac0133f7cd..446acb6ba967 100644 --- a/Makefile +++ b/Makefile @@ -644,8 +644,9 @@ ifdef building_out_of_srctree quiet_cmd_makefile = GEN Makefile cmd_makefile = { \ - echo "\# Automatically generated by $(srctree)/Makefile: don't edit"; \ - echo "include $(srctree)/Makefile"; \ + echo "\# Automatically generated by $(abs_srctree)/Makefile: don't edit"; \ + echo "export KBUILD_OUTPUT = $(CURDIR)"; \ + echo "include $(abs_srctree)/Makefile"; \ } > Makefile outputmakefile: -- cgit v1.2.3 From a2a45ebee0969b804b1d474a930001a83c954140 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:38 +0900 Subject: kbuild: make wrapper Makefile more convenient for external modules When Kbuild starts building in a separate output directory, it generates a wrapper Makefile, allowing you to invoke 'make' from the output directory. This commit makes it more convenient, so you can invoke 'make' without M= or MO=. First, you need to build external modules in a separate directory: $ make M=/path/to/module/source/dir MO=/path/to/module/build/dir Once the wrapper Makefile is generated in /path/to/module/build/dir, you can proceed as follows: $ cd /path/to/module/build/dir $ make Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 446acb6ba967..f0bce5081d53 100644 --- a/Makefile +++ b/Makefile @@ -642,10 +642,20 @@ ifdef building_out_of_srctree # At the same time when output Makefile generated, generate .gitignore to # ignore whole output directory +ifdef KBUILD_EXTMOD +print_env_for_makefile = \ + echo "export KBUILD_OUTPUT = $(objtree)"; \ + echo "export KBUILD_EXTMOD = $(realpath $(srcroot))" ; \ + echo "export KBUILD_EXTMOD_OUTPUT = $(CURDIR)" +else +print_env_for_makefile = \ + echo "export KBUILD_OUTPUT = $(CURDIR)" +endif + quiet_cmd_makefile = GEN Makefile cmd_makefile = { \ echo "\# Automatically generated by $(abs_srctree)/Makefile: don't edit"; \ - echo "export KBUILD_OUTPUT = $(CURDIR)"; \ + $(print_env_for_makefile); \ echo "include $(abs_srctree)/Makefile"; \ } > Makefile -- cgit v1.2.3 From 8cd07cc6c88cab5cbfe5dd83aacf860a209eb521 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 10 Nov 2024 10:34:39 +0900 Subject: kbuild: allow to start building external modules in any directory Unless an explicit O= option is provided, external module builds must start from the kernel directory. This can be achieved by using the -C option: $ make -C /path/to/kernel M=/path/to/external/module This commit allows starting external module builds from any directory, so you can also do the following: $ make -f /path/to/kernel/Makefile M=/path/to/external/module The key difference is that the -C option changes the working directory and parses the Makefile located there, while the -f option only specifies the Makefile to use. As shown in the examples in Documentation/kbuild/modules.rst, external modules usually have a wrapper Makefile that allows you to build them without specifying any make arguments. The Makefile typically contains a rule as follows: KDIR ?= /path/to/kernel default: $(MAKE) -C $(KDIR) M=$(CURDIR) $(MAKECMDGOALS) The log will appear as follows: $ make make -C /path/to/kernel M=/path/to/external/module make[1]: Entering directory '/path/to/kernel' make[2]: Entering directory '/path/to/external/module' CC [M] helloworld.o MODPOST Module.symvers CC [M] helloworld.mod.o CC [M] .module-common.o LD [M] helloworld.ko make[2]: Leaving directory '/path/to/external/module' make[1]: Leaving directory '/path/to/kernel' This changes the working directory twice because the -C option first switches to the kernel directory, and then Kbuild internally recurses back to the external module directory. With this commit, the wrapper Makefile can directly include the kernel Makefile: KDIR ?= /path/to/kernel export KBUILD_EXTMOD := $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) include $(KDIR)/Makefile This avoids unnecessary sub-make invocations: $ make CC [M] helloworld.o MODPOST Module.symvers CC [M] helloworld.mod.o CC [M] .module-common.o LD [M] helloworld.ko Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Documentation/kbuild/modules.rst | 21 +++++++++++++++++++++ Makefile | 8 ++++++-- 2 files changed, 27 insertions(+), 2 deletions(-) (limited to 'Makefile') diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst index a01f3754c7fc..101de236cd0c 100644 --- a/Documentation/kbuild/modules.rst +++ b/Documentation/kbuild/modules.rst @@ -59,6 +59,12 @@ Command Syntax $ make -C /lib/modules/`uname -r`/build M=$PWD modules_install + Starting from Linux 6.13, you can use the -f option instead of -C. This + will avoid unnecessary change of the working directory. The external + module will be output to the directory where you invoke make. + + $ make -f /lib/modules/`uname -r`/build/Makefile M=$PWD + Options ------- @@ -221,6 +227,21 @@ Separate Kbuild File and Makefile consisting of several hundred lines, and here it really pays off to separate the kbuild part from the rest. + Linux 6.13 and later support another way. The external module Makefile + can include the kernel Makefile directly, rather than invoking sub Make. + + Example 3:: + + --> filename: Kbuild + obj-m := 8123.o + 8123-y := 8123_if.o 8123_pci.o + + --> filename: Makefile + KDIR ?= /lib/modules/$(shell uname -r)/build + export KBUILD_EXTMOD := $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) + include $(KDIR)/Makefile + + Building Multiple Modules ------------------------- diff --git a/Makefile b/Makefile index f0bce5081d53..b77dae5aa03c 100644 --- a/Makefile +++ b/Makefile @@ -189,9 +189,13 @@ ifdef KBUILD_EXTMOD objtree := $(realpath $(KBUILD_OUTPUT)) $(if $(objtree),,$(error specified kernel directory "$(KBUILD_OUTPUT)" does not exist)) else - objtree := $(CURDIR) + objtree := $(abs_srctree) endif - output := $(or $(KBUILD_EXTMOD_OUTPUT),$(KBUILD_EXTMOD)) + # If Make is invoked from the kernel directory (either kernel + # source directory or kernel build directory), external modules + # are built in $(KBUILD_EXTMOD) for backward compatibility, + # otherwise, built in the current directory. + output := $(or $(KBUILD_EXTMOD_OUTPUT),$(if $(filter $(CURDIR),$(objtree) $(abs_srctree)),$(KBUILD_EXTMOD))) # KBUILD_EXTMOD might be a relative path. Remember its absolute path before # Make changes the working directory. srcroot := $(realpath $(KBUILD_EXTMOD)) -- cgit v1.2.3 From 91ca8be3c402c566de75685ce99c714b0e8638bf Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 12 Nov 2024 02:17:41 +0900 Subject: kbuild: remove support for single %.symtypes build rule This rule is unnecessary because you can generate foo/bar.symtypes as a side effect using: $ make KBUILD_SYMTYPES=1 foo/bar.o While compiling *.o is slower than preprocessing, the impact is negligible. I prioritize keeping the code simpler. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 2 +- scripts/Makefile.build | 22 ++++------------------ 2 files changed, 5 insertions(+), 19 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index b77dae5aa03c..215d5fd95a28 100644 --- a/Makefile +++ b/Makefile @@ -301,7 +301,7 @@ no-dot-config-targets := $(clean-targets) \ outputmakefile rustavailable rustfmt rustfmtcheck no-sync-config-targets := $(no-dot-config-targets) %install modules_sign kernelrelease \ image_name -single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.rsi %.s %.symtypes %/ +single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.rsi %.s %/ config-build := mixed-build := diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 628e0ce28dc8..15a88f4d6ef6 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -108,19 +108,13 @@ $(obj)/%.i: $(obj)/%.c FORCE $(call if_changed_dep,cpp_i_c) genksyms = $(objtree)/scripts/genksyms/genksyms \ - $(if $(1), -T $(2)) \ - $(if $(KBUILD_PRESERVE), -p) \ - $(addprefix -r , $(wildcard $(2:.symtypes=.symref))) + $(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes)) \ + $(if $(KBUILD_PRESERVE), -p) \ + $(addprefix -r , $(wildcard $(@:.o=.symref))) # These mirror gensymtypes_S and co below, keep them in synch. cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms) -quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ - cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null - -$(obj)/%.symtypes : $(obj)/%.c FORCE - $(call cmd,cc_symtypes_c) - # LLVM assembly # Generate .ll files from .c quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ @@ -158,8 +152,7 @@ ifdef CONFIG_MODVERSIONS gen_symversions = \ if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \ - $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ - >> $(dot-target).cmd; \ + $(cmd_gensymtypes_$1) >> $(dot-target).cmd; \ fi cmd_gen_symversions_c = $(call gen_symversions,c) @@ -323,13 +316,6 @@ cmd_gensymtypes_S = \ $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \ $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms) -quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ - cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null - -$(obj)/%.symtypes : $(obj)/%.S FORCE - $(call cmd,cc_symtypes_S) - - quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< -- cgit v1.2.3 From e397a603e49cc7c7c113fad9f55a09637f290c34 Mon Sep 17 00:00:00 2001 From: Parth Pancholi Date: Thu, 14 Nov 2024 15:56:44 +0100 Subject: kbuild: switch from lz4c to lz4 for compression Replace lz4c with lz4 for kernel image compression. Although lz4 and lz4c are functionally similar, lz4c has been deprecated upstream since 2018. Since as early as Ubuntu 16.04 and Fedora 25, lz4 and lz4c have been packaged together, making it safe to update the requirement from lz4c to lz4. Consequently, some distributions and build systems, such as OpenEmbedded, have fully transitioned to using lz4. OpenEmbedded core adopted this change in commit fe167e082cbd ("bitbake.conf: require lz4 instead of lz4c"), causing compatibility issues when building the mainline kernel in the latest OpenEmbedded environment, as seen in the errors below. This change also updates the LZ4 compression commands to make it backward compatible by replacing stdin and stdout with the '-' option, due to some unclear reason, the stdout keyword does not work for lz4 and '-' works for both. In addition, this modifies the legacy '-c1' with '-9' which is also compatible with both. This fixes the mainline kernel build failures with the latest master OpenEmbedded builds associated with the mentioned compatibility issues. LZ4 arch/arm/boot/compressed/piggy_data /bin/sh: 1: lz4c: not found ... ... ERROR: oe_runmake failed Link: https://github.com/lz4/lz4/pull/553 Suggested-by: Francesco Dolcini Signed-off-by: Parth Pancholi Signed-off-by: Masahiro Yamada --- Makefile | 2 +- scripts/Makefile.lib | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 215d5fd95a28..f7f43c8997ae 100644 --- a/Makefile +++ b/Makefile @@ -533,7 +533,7 @@ KGZIP = gzip KBZIP2 = bzip2 KLZOP = lzop LZMA = lzma -LZ4 = lz4c +LZ4 = lz4 XZ = xz ZSTD = zstd diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 01040a767c1d..7395200538da 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -425,10 +425,10 @@ quiet_cmd_lzo_with_size = LZO $@ cmd_lzo_with_size = { cat $(real-prereqs) | $(KLZOP) -9; $(size_append); } > $@ quiet_cmd_lz4 = LZ4 $@ - cmd_lz4 = cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout > $@ + cmd_lz4 = cat $(real-prereqs) | $(LZ4) -l -9 - - > $@ quiet_cmd_lz4_with_size = LZ4 $@ - cmd_lz4_with_size = { cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout; \ + cmd_lz4_with_size = { cat $(real-prereqs) | $(LZ4) -l -9 - -; \ $(size_append); } > $@ # U-Boot mkimage -- cgit v1.2.3