kernel/rust/Makefile, branch linux-6.14.y

rust: kbuild: skip `--remap-path-prefix` for `rustdoc`

2025-05-02T06:02:15Z

commit 2c8725c1dca3de043670b38592b1b43105322496 upstream. `rustdoc` only recognizes `--remap-path-prefix` starting with Rust 1.81.0, which is later than on minimum, so we cannot pass it unconditionally. Otherwise, we get: error: Unrecognized option: 'remap-path-prefix' Note that `rustc` (the compiler) does recognize the flag since a long time ago (1.26.0). Moreover, `rustdoc` since Rust 1.82.0 ICEs in out-of-tree builds when using `--remap-path-prefix`. The issue has been reduced and reported upstream [1]. Thus workaround both issues by simply skipping the flag when generating the docs -- it is not critical there anyway. The ICE does not reproduce under `--test`, but we still need to skip the flag as well for `RUSTDOC TK` since it is not recognized. Fixes: dbdffaf50ff9 ("kbuild, rust: use -fremap-path-prefix to make paths relative") Link: https://github.com/rust-lang/rust/issues/138520 [1] Signed-off-by: Miguel Ojeda Reviewed-by: Tamir Duberstein Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

rust: kbuild: Don't export __pfx symbols

2025-04-25T08:51:00Z

commit c59026c0570a2a97ce2e7d5ae5e9c48fc841542b upstream. With CONFIG_PREFIX_SYMBOLS, objtool adds __pfx prefix symbols to claim the compiler emitted call padding bytes. When CONFIG_X86_KERNEL_IBT is not selected, the symbols are added to individual object files and for Rust objects, they end up being exported, resulting in warnings with CONFIG_GENDWARFKSYMS as the symbols have no debugging information: warning: gendwarfksyms: symbol_print_versions: no information for symbol __pfx_rust_helper_put_task_struct warning: gendwarfksyms: symbol_print_versions: no information for symbol __pfx_rust_helper_task_euid warning: gendwarfksyms: symbol_print_versions: no information for symbol __pfx_rust_helper_readq_relaxed ... Filter out the __pfx prefix from exported symbols similarly to the existing __cfi and __odr_asan prefixes. Signed-off-by: Sami Tolvanen Reviewed-by: Alice Ryhl Cc: stable@vger.kernel.org Fixes: ac61506bf2d1 ("rust: Use gendwarfksyms + extended modversions for CONFIG_MODVERSIONS") Link: https://lore.kernel.org/r/20250318231815.917621-2-samitolvanen@google.com Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

rust: Fix enabling Rust and building with GCC for LoongArch

2025-04-10T12:44:43Z

commit 13c23cb4ed09466d73f1beae8956810b95add6ef upstream. This patch fixes a build issue on LoongArch when Rust is enabled and compiled with GCC by explicitly setting the bindgen target and skipping C flags that Clang doesn't support. Cc: stable@vger.kernel.org Acked-by: Miguel Ojeda Signed-off-by: WANG Rui Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

rust: kbuild: do not export generated KASAN ODR symbols

2025-02-06T18:47:04Z

ASAN generates special synthetic symbols to help check for ODR violations. These synthetic symbols lack debug information, so gendwarfksyms emits warnings when processing them. No code should ever have a dependency on these symbols, so we should not be exporting them, just like the __cfi symbols. Signed-off-by: Matthew Maurer Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250122-gendwarfksyms-kasan-rust-v1-1-5ee5658f4fb6@google.com [ Fixed typo in commit message. Slightly reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

rust: kbuild: add -fzero-init-padding-bits to bindgen_skip_cflags

2025-02-06T16:13:13Z

This seems to break the build when building with gcc15: Unable to generate bindings: ClangDiagnostic("error: unknown argument: '-fzero-init-padding-bits=all'\n") Thus skip that flag. Signed-off-by: Justin M. Forbes Fixes: dce4aab8441d ("kbuild: Use -fzero-init-padding-bits=all") Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20250129215003.1736127-1-jforbes@fedoraproject.org [ Slightly reworded commit. - Miguel ] Signed-off-by: Miguel Ojeda

rust: kbuild: use host dylib naming in rusttestlib-kernel

2025-02-05T23:15:27Z

There seems to have been merge skew between commit b2c261fa8629 ("rust: kbuild: expand rusttest target for macros") and commit 0730422bced5 ("rust: use host dylib naming convention to support macOS") ; the latter replaced `libmacros.so` with `$(libmacros_name)` and the former added an instance of `libmacros.so`. The former was not yet applied when the latter was sent, resulting in a stray `libmacros.so`. Replace the stray with `$(libmacros_name)` to allow `rusttest` to build on macOS. Fixes: 0730422bced5 ("rust: use host dylib naming convention to support macOS") Signed-off-by: Tamir Duberstein Link: https://lore.kernel.org/r/20250201-fix-mac-build-again-v1-1-ca665f5d7de7@gmail.com [ Slightly reworded title. - Miguel ] Signed-off-by: Miguel Ojeda

Merge tag 'kbuild-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2025-01-31T20:07:07Z

Pull Kbuild updates from Masahiro Yamada: - Support multiple hook locations for maint scripts of Debian package - Remove 'cpio' from the build tool requirement - Introduce gendwarfksyms tool, which computes CRCs for export symbols based on the DWARF information - Support CONFIG_MODVERSIONS for Rust - Resolve all conflicts in the genksyms parser - Fix several syntax errors in genksyms * tag 'kbuild-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (64 commits) kbuild: fix Clang LTO with CONFIG_OBJTOOL=n kbuild: Strip runtime const RELA sections correctly kconfig: fix memory leak in sym_warn_unmet_dep() kconfig: fix file name in warnings when loading KCONFIG_DEFCONFIG_LIST genksyms: fix syntax error for attribute before init-declarator genksyms: fix syntax error for builtin (u)int*x*_t types genksyms: fix syntax error for attribute after 'union' genksyms: fix syntax error for attribute after 'struct' genksyms: fix syntax error for attribute after abstact_declarator genksyms: fix syntax error for attribute before nested_declarator genksyms: fix syntax error for attribute before abstract_declarator genksyms: decouple ATTRIBUTE_PHRASE from type-qualifier genksyms: record attributes consistently for init-declarator genksyms: restrict direct-declarator to take one parameter-type-list genksyms: restrict direct-abstract-declarator to take one parameter-type-list genksyms: remove Makefile hack genksyms: fix last 3 shift/reduce conflicts genksyms: fix 6 shift/reduce conflicts and 5 reduce/reduce conflicts genksyms: reduce type_qualifier directly to decl_specifier genksyms: rename cvar_qualifier to type_qualifier ...

rust: Use gendwarfksyms + extended modversions for CONFIG_MODVERSIONS

2025-01-17T23:51:48Z

Previously, two things stopped Rust from using MODVERSIONS: 1. Rust symbols are occasionally too long to be represented in the original versions table 2. Rust types cannot be properly hashed by the existing genksyms approach because: * Looking up type definitions in Rust is more complex than C * Type layout is potentially dependent on the compiler in Rust, not just the source type declaration. CONFIG_EXTENDED_MODVERSIONS addresses the first point, and CONFIG_GENDWARFKSYMS the second. If Rust wants to use MODVERSIONS, allow it to do so by selecting both features. Signed-off-by: Sami Tolvanen Co-developed-by: Matthew Maurer Signed-off-by: Matthew Maurer Signed-off-by: Masahiro Yamada

kbuild: rust: add PROCMACROLDFLAGS

2025-01-15T08:53:54Z

These are flags to be passed when linking proc macros for the Rust toolchain. If unset, it defaults to $(KBUILD_HOSTLDFLAGS). This is needed because the list of flags to link hostprogs is not necessarily the same as the list of flags used to link libmacros.so. When we build proc macros, we need the latter, not the former (e.g. when using a Rust compiler binary linked to a different C library than host programs). To distinguish between the two, introduce this new variable to stand out from KBUILD_HOSTLDFLAGS used to link other host progs. Signed-off-by: HONG Yifan Link: https://lore.kernel.org/r/20241017210430.2401398-2-elsk@google.com [ v3: - `export`ed the variable. Otherwise it would not be visible in `rust/Makefile`. - Removed "additional" from the documentation and commit message, since this actually replaces the other flags, unlike other cases. - Added example of use case to documentation and commit message. Thanks Alice for the details on what Google needs! - Instead of `HOSTLDFLAGS`, used `KBUILD_HOSTLDFLAGS` as the fallback to preserve the previous behavior as much as possible, as discussed with Alice/Yifan. Thus moved the variable down too (currently we do not modify `KBUILD_HOSTLDFLAGS` elsewhere) and avoided mentioning `HOSTLDFLAGS` directly in the documentation. - Fixed documentation header formatting. - Reworded slightly. - Miguel ] Tested-by: Alice Ryhl Reviewed-by: Alice Ryhl Reviewed-by: HONG Yifan Acked-by: Masahiro Yamada Link: https://lore.kernel.org/r/20241112184455.855133-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda

rust: use host dylib naming convention to support macOS

2025-01-10T00:01:24Z

Because the `macros` crate exposes procedural macros, it must be compiled as a dynamic library (so it can be loaded by the compiler at compile-time). Before this change the resulting artifact was always named `libmacros.so`, which works on hosts where this matches the naming convention for dynamic libraries. However the proper name on macOS would be `libmacros.dylib`. This turns out to matter even when the dependency is passed with a path (`--extern macros=path/to/libmacros.so` rather than `--extern macros`) because rustc uses the file name to infer the type of the library (see link). This is because there's no way to specify both the path to and the type of the external library via CLI flags. The compiler could speculatively parse the file to determine its type, but it does not do so today. This means that libraries that match neither rustc's naming convention for static libraries nor the platform's naming convention for dynamic libraries are *rejected*. The only solution I've found is to follow the host platform's naming convention. This patch does that by querying the compiler to determine the appropriate name for the artifact. This allows the kernel to build with CONFIG_RUST=y on macOS. Link: https://github.com/rust-lang/rust/blob/d829780/compiler/rustc_metadata/src/locator.rs#L728-L752 Tested-by: Daniel Gomez Co-developed-by: Fiona Behrens Signed-off-by: Fiona Behrens Signed-off-by: Tamir Duberstein Tested-by: Andreas Hindborg Link: https://lore.kernel.org/r/20241216-b4-dylib-host-macos-v7-1-cfc507681447@gmail.com [ Added `MAKEFLAGS=`s to avoid jobserver warnings. Removed space. Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda