linux/scripts/Makefile.build, branch v6.14

kbuild: fix Clang LTO with CONFIG_OBJTOOL=n

2025-01-31T19:28:05Z

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

kbuild: Add gendwarfksyms as an alternative to genksyms

2025-01-10T16:25:26Z

When MODVERSIONS is enabled, allow selecting gendwarfksyms as the implementation, but default to genksyms. Signed-off-by: Sami Tolvanen Signed-off-by: Masahiro Yamada

Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-11-30T21:41:50Z

Pull Kbuild updates from Masahiro Yamada: - Add generic support for built-in boot DTB files - Enable TAB cycling for dialog buttons in nconfig - Fix issues in streamline_config.pl - Refactor Kconfig - Add support for Clang's AutoFDO (Automatic Feedback-Directed Optimization) - Add support for Clang's Propeller, a profile-guided optimization. - Change the working directory to the external module directory for M= builds - Support building external modules in a separate output directory - Enable objtool for *.mod.o and additional kernel objects - Use lz4 instead of deprecated lz4c - Work around a performance issue with "git describe" - Refactor modpost * tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits) kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms gitignore: Don't ignore 'tags' directory kbuild: add dependency from vmlinux to resolve_btfids modpost: replace tdb_hash() with hash_str() kbuild: deb-pkg: add python3:native to build dependency genksyms: reduce indentation in export_symbol() modpost: improve error messages in device_id_check() modpost: rename alias symbol for MODULE_DEVICE_TABLE() modpost: rename variables in handle_moddevtable() modpost: move strstarts() to modpost.h modpost: convert do_usb_table() to a generic handler modpost: convert do_of_table() to a generic handler modpost: convert do_pnp_device_entry() to a generic handler modpost: convert do_pnp_card_entries() to a generic handler modpost: call module_alias_printf() from all do_*_entry() functions modpost: pass (struct module *) to do_*_entry() functions modpost: remove DEF_FIELD_ADDR_VAR() macro modpost: deduplicate MODULE_ALIAS() for all drivers modpost: introduce module_alias_printf() helper modpost: remove unnecessary check in do_acpi_entry() ...

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: remove support for single %.symtypes build rule

2024-11-27T23:11:55Z

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

kbuild: do not pass -r to genksyms when *.symref does not exist

2024-11-27T23:11:55Z

There is no need to pass '-r /dev/null', which is no-op. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier

kbuild: change working directory to external module directory with M=

2024-11-27T23:10:23Z

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

kbuild: add $(objtree)/ prefix to some in-kernel build artifacts

2024-11-27T00:38:27Z

$(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

Merge tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux

2024-11-26T22:00:26Z

Pull rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Enable a series of lints, including safety-related ones, e.g. the compiler will now warn about missing safety comments, as well as unnecessary ones. How safety documentation is organized is a frequent source of review comments, thus having the compiler guide new developers on where they are expected (and where not) is very nice. - Start using '#[expect]': an interesting feature in Rust (stabilized in 1.81.0) that makes the compiler warn if an expected warning was _not_ emitted. This is useful to avoid forgetting cleaning up locally ignored diagnostics ('#[allow]'s). - Introduce '.clippy.toml' configuration file for Clippy, the Rust linter, which will allow us to tweak its behaviour. For instance, our first use cases are declaring a disallowed macro and, more importantly, enabling the checking of private items. - Lints-related fixes and cleanups related to the items above. - Migrate from 'receiver_trait' to 'arbitrary_self_types': to get the kernel into stable Rust, one of the major pieces of the puzzle is the support to write custom types that can be used as 'self', i.e. as receivers, since the kernel needs to write types such as 'Arc' that common userspace Rust would not. 'arbitrary_self_types' has been accepted to become stable, and this is one of the steps required to get there. - Remove usage of the 'new_uninit' unstable feature. - Use custom C FFI types. Includes a new 'ffi' crate to contain our custom mapping, instead of using the standard library 'core::ffi' one. The actual remapping will be introduced in a later cycle. - Map '__kernel_{size_t,ssize_t,ptrdiff_t}' to 'usize'/'isize' instead of 32/64-bit integers. - Fix 'size_t' in bindgen generated prototypes of C builtins. - Warn on bindgen < 0.69.5 and libclang >= 19.1 due to a double issue in the projects, which we managed to trigger with the upcoming tracepoint support. It includes a build test since some distributions backported the fix (e.g. Debian -- thanks!). All major distributions we list should be now OK except Ubuntu non-LTS. 'macros' crate: - Adapt the build system to be able run the doctests there too; and clean up and enable the corresponding doctests. 'kernel' crate: - Add 'alloc' module with generic kernel allocator support and remove the dependency on the Rust standard library 'alloc' and the extension traits we used to provide fallible methods with flags. Add the 'Allocator' trait and its implementations '{K,V,KV}malloc'. Add the 'Box' type (a heap allocation for a single value of type 'T' that is also generic over an allocator and considers the kernel's GFP flags) and its shorthand aliases '{K,V,KV}Box'. Add 'ArrayLayout' type. Add 'Vec' (a contiguous growable array type) and its shorthand aliases '{K,V,KV}Vec', including iterator support. For instance, now we may write code such as: let mut v = KVec::new(); v.push(1, GFP_KERNEL)?; assert_eq!(&v, &[1]); Treewide, move as well old users to these new types. - 'sync' module: add global lock support, including the 'GlobalLockBackend' trait; the 'Global{Lock,Guard,LockedBy}' types and the 'global_lock!' macro. Add the 'Lock::try_lock' method. - 'error' module: optimize 'Error' type to use 'NonZeroI32' and make conversion functions public. - 'page' module: add 'page_align' function. - Add 'transmute' module with the existing 'FromBytes' and 'AsBytes' traits. - 'block::mq::request' module: improve rendered documentation. - 'types' module: extend 'Opaque' type documentation and add simple examples for the 'Either' types. drm/panic: - Clean up a series of Clippy warnings. Documentation: - Add coding guidelines for lints and the '#[expect]' feature. - Add Ubuntu to the list of distributions in the Quick Start guide. MAINTAINERS: - Add Danilo Krummrich as maintainer of the new 'alloc' module. And a few other small cleanups and fixes" * tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux: (82 commits) rust: alloc: Fix `ArrayLayout` allocations docs: rust: remove spurious item in `expect` list rust: allow `clippy::needless_lifetimes` rust: warn on bindgen < 0.69.5 and libclang >= 19.1 rust: use custom FFI integer types rust: map `__kernel_size_t` and friends also to usize/isize rust: fix size_t in bindgen prototypes of C builtins rust: sync: add global lock support rust: macros: enable the rest of the tests rust: macros: enable paste! use from macro_rules! rust: enable macros::module! tests rust: kbuild: expand rusttest target for macros rust: types: extend `Opaque` documentation rust: block: fix formatting of `kernel::block::mq::request` module rust: macros: fix documentation of the paste! macro rust: kernel: fix THIS_MODULE header path in ThisModule doc comment rust: page: add Rust version of PAGE_ALIGN rust: helpers: remove unnecessary header includes rust: exports: improve grammar in commentary drm/panic: allow verbose version check ...