user/sven/linux.git/scripts/Makefile.lib, branch v6.13.4

kbuild: fix Clang LTO with CONFIG_OBJTOOL=n

2025-02-08T09:02:18Z

[ Upstream commit 695ed93bb30e03e9f826ee70abdd83f970741a37 ] Since commit bede169618c6 ("kbuild: enable objtool for *.mod.o and additional kernel objects"), Clang LTO builds do not perform any optimizations when CONFIG_OBJTOOL is disabled (e.g., for ARCH=arm64). This is because every LLVM bitcode file is immediately converted to ELF format before the object files are linked together. This commit fixes the breakage. Fixes: bede169618c6 ("kbuild: enable objtool for *.mod.o and additional kernel objects") Reported-by: Yonghong Song Signed-off-by: Masahiro Yamada Tested-by: Yonghong Song Signed-off-by: Sasha Levin

kbuild: switch from lz4c to lz4 for compression

2024-11-27T23:11:56Z

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

kbuild: enable objtool for *.mod.o and additional kernel objects

2024-11-27T23:11:55Z

Currently, objtool is disabled in scripts/Makefile.{modfinal,vmlinux}. This commit moves rule_cc_o_c and rule_as_o_S to scripts/Makefile.lib and set objtool-enabled to y there. With this change, *.mod.o, .module-common.o, builtin-dtb.o, and vmlinux.export.o will now be covered by objtool. Signed-off-by: Masahiro Yamada

kbuild: move cmd_cc_o_c and cmd_as_o_S to scripts/Malefile.lib

2024-11-27T23:11:55Z

The cmd_cc_o_c and cmd_as_o_S macros are duplicated in scripts/Makefile.{build,modfinal,vmlinux}. This commit factors them out to scripts/Makefile.lib. No functional changes are intended. Signed-off-by: Masahiro Yamada

kbuild: support building external modules in a separate build directory

2024-11-27T23:11:55Z

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

kbuild: Add Propeller configuration for kernel build

2024-11-27T00:38:27Z

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

kbuild: Add AutoFDO support for Clang build

2024-11-06T13:41:09Z

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

Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux

2024-09-25T17:25:40Z

Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up objtool warnings), teach objtool about 'noreturn' Rust symbols and mimic '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we should be objtool-warning-free, so enable it to run for all Rust object files. - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support. - Support 'RUSTC_VERSION', including re-config and re-build on change. - Split helpers file into several files in a folder, to avoid conflicts in it. Eventually those files will be moved to the right places with the new build system. In addition, remove the need to manually export the symbols defined there, reusing existing machinery for that. - Relax restriction on configurations with Rust + GCC plugins to just the RANDSTRUCT plugin. 'kernel' crate: - New 'list' module: doubly-linked linked list for use with reference counted values, which is heavily used by the upcoming Rust Binder. This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed unique for the given ID), 'AtomicTracker' (tracks whether a 'ListArc' exists using an atomic), 'ListLinks' (the prev/next pointers for an item in a linked list), 'List' (the linked list itself), 'Iter' (an iterator over a 'List'), 'Cursor' (a cursor into a 'List' that allows to remove elements), 'ListArcField' (a field exclusively owned by a 'ListArc'), as well as support for heterogeneous lists. - New 'rbtree' module: red-black tree abstractions used by the upcoming Rust Binder. This includes 'RBTree' (the red-black tree itself), 'RBTreeNode' (a node), 'RBTreeNodeReservation' (a memory reservation for a node), 'Iter' and 'IterMut' (immutable and mutable iterators), 'Cursor' (bidirectional cursor that allows to remove elements), as well as an entry API similar to the Rust standard library one. - 'init' module: add 'write_[pin_]init' methods and the 'InPlaceWrite' trait. Add the 'assert_pinned!' macro. - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by introducing an associated type in the trait. - 'alloc' module: add 'drop_contents' method to 'BoxExt'. - 'types' module: implement the 'ForeignOwnable' trait for 'Pin>' and improve the trait's documentation. In addition, add the 'into_raw' method to the 'ARef' type. - 'error' module: in preparation for the upcoming Rust support for 32-bit architectures, like arm, locally allow Clippy lint for those. Documentation: - https://rust.docs.kernel.org has been announced, so link to it. - Enable rustdoc's "jump to definition" feature, making its output a bit closer to the experience in a cross-referencer. - Debian Testing now also provides recent Rust releases (outside of the freeze period), so add it to the list. MAINTAINERS: - Trevor is joining as reviewer of the "RUST" entry. And a few other small bits" * tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux: (54 commits) kasan: rust: Add KASAN smoke test via UAF kbuild: rust: Enable KASAN support rust: kasan: Rust does not support KHWASAN kbuild: rust: Define probing macros for rustc kasan: simplify and clarify Makefile rust: cfi: add support for CFI_CLANG with Rust cfi: add CONFIG_CFI_ICALL_NORMALIZE_INTEGERS rust: support for shadow call stack sanitizer docs: rust: include other expressions in conditional compilation section kbuild: rust: replace proc macros dependency on `core.o` with the version text kbuild: rust: rebuild if the version text changes kbuild: rust: re-run Kconfig if the version text changes kbuild: rust: add `CONFIG_RUSTC_VERSION` rust: avoid `box_uninit_write` feature MAINTAINERS: add Trevor Gross as Rust reviewer rust: rbtree: add `RBTree::entry` rust: rbtree: add cursor rust: rbtree: add mutable iterator rust: rbtree: add iterator rust: rbtree: add red-black tree implementation backed by the C version ...

Merge tag 'kbuild-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-09-24T20:02:06Z

Pull Kbuild updates from Masahiro Yamada: - Support cross-compiling linux-headers Debian package and kernel-devel RPM package - Add support for the linux-debug Pacman package - Improve module rebuilding speed by factoring out the common code to scripts/module-common.c - Separate device tree build rules into scripts/Makefile.dtbs - Add a new script to generate modules.builtin.ranges, which is useful for tracing tools to find symbols in built-in modules - Refactor Kconfig and misc tools - Update Kbuild and Kconfig documentation * tag 'kbuild-v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (51 commits) kbuild: doc: replace "gcc" in external module description kbuild: doc: describe the -C option precisely for external module builds kbuild: doc: remove the description about shipped files kbuild: doc: drop section numbering, use references in modules.rst kbuild: doc: throw out the local table of contents in modules.rst kbuild: doc: remove outdated description of the limitation on -I usage kbuild: doc: remove description about grepping CONFIG options kbuild: doc: update the description about Kbuild/Makefile split kbuild: remove unnecessary export of RUST_LIB_SRC kbuild: remove append operation on cmd_ld_ko_o kconfig: cache expression values kconfig: use hash table to reuse expressions kconfig: refactor expr_eliminate_dups() kconfig: add comments to expression transformations kconfig: change some expr_*() functions to bool scripts: move hash function from scripts/kconfig/ to scripts/include/ kallsyms: change overflow variable to bool type kallsyms: squash output_address() kbuild: add install target for modules.builtin.ranges scripts: add verifier script for builtin module range data ...

kbuild: rust: Enable KASAN support

2024-09-16T16:04:37Z

Rust supports KASAN via LLVM, but prior to this patch, the flags aren't set properly. Suggested-by: Miguel Ojeda Signed-off-by: Matthew Maurer Reviewed-by: Andrey Konovalov Link: https://lore.kernel.org/r/20240820194910.187826-4-mmaurer@google.com [ Applied "SW_TAGS KASAN" nit. - Miguel ] Signed-off-by: Miguel Ojeda