Yonghong Song says: ==================== To build kernel with clang, people typically use make -j60 LLVM=1 LLVM_IAS=1 LLVM_IAS=1 is not required for non-LTO build but is required for LTO build. In my environment, I am always having LLVM_IAS=1 regardless of whether LTO is enabled or not. After kernel is build with clang, the following command can be used to build selftests with clang: make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 I am using latest bpf-next kernel code base and latest clang built from source from https://github.com/llvm/llvm-project.git Using earlier version of llvm may have compilation errors, see tools/testing/selftests/bpf due to continuous development in llvm bpf features and selftests to use these features. To run bpf selftest properly, you need have certain necessary kernel configs like at: bpf-next:tools/testing/selftests/bpf/config (not that this is not a complete .config file and some other configs might still be needed.) Currently, using the above command, some compilations still use gcc and there are also compilation errors and warnings. This patch set intends to fix these issues. Patch #1 and #2 fixed the issue so clang/clang++ is used instead of gcc/g++. Patch #3 fixed a compilation failure. Patch #4 and #5 fixed various compiler warnings. Changelog: v2 -> v3: . more test environment description in cover letter. (Sedat) . use a different fix, but similar to other use in selftests/bpf Makefile, to exclude header files from CXX compilation command line. (Andrii) . fix codes instead of adding -Wno-format-security. (Andrii) v1 -> v2: . add -Wno-unused-command-line-argument and -Wno-format-security for clang only as (1). gcc does not exhibit those warnings, and (2). -Wno-unused-command-line-argument is only supported by clang. (Sedat) ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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