diff options
| author | Miguel Ojeda <ojeda@kernel.org> | 2026-08-16 15:32:33 +0200 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2026-08-23 21:27:17 +0200 |
| commit | 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 (patch) | |
| tree | 93a1ed1d337bc53adf1e572c2586d347703b286e /arch/arm64/Kconfig.debug | |
| download | linux-stable-5febf432df1cfa5b25d99b54c32103fafbdd0eb9.tar.gz linux-stable-5febf432df1cfa5b25d99b54c32103fafbdd0eb9.zip | |
kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted
Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:
vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd
The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.
This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.
Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.
Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'arch/arm64/Kconfig.debug')
| -rw-r--r-- | arch/arm64/Kconfig.debug | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug new file mode 100644 index 000000000..265c44610 --- /dev/null +++ b/arch/arm64/Kconfig.debug @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config PID_IN_CONTEXTIDR + bool "Write the current PID to the CONTEXTIDR register" + help + Enabling this option causes the kernel to write the current PID to + the CONTEXTIDR register, at the expense of some additional + instructions during context switch. Say Y here only if you are + planning to use hardware trace tools with this kernel. + +config DEBUG_EFI + depends on EFI && DEBUG_INFO + bool "UEFI debugging" + help + Enable this option to include EFI specific debugging features into + the kernel that are only useful when using a debug build of the + UEFI firmware + +config ARM64_RELOC_TEST + depends on m + tristate "Relocation testing module" + +source "drivers/hwtracing/coresight/Kconfig" |