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| 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 /drivers/virt/acrn/Kconfig | |
| 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 'drivers/virt/acrn/Kconfig')
| -rw-r--r-- | drivers/virt/acrn/Kconfig | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/virt/acrn/Kconfig b/drivers/virt/acrn/Kconfig new file mode 100644 index 000000000..3e1a61c9d --- /dev/null +++ b/drivers/virt/acrn/Kconfig @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0 +config ACRN_HSM + tristate "ACRN Hypervisor Service Module" + depends on ACRN_GUEST + select EVENTFD + help + ACRN Hypervisor Service Module (HSM) is a kernel module which + communicates with ACRN userspace through ioctls and talks to + the ACRN Hypervisor through hypercalls. HSM will only run in + a privileged management VM, called Service VM, to manage User + VMs and do I/O emulation. Not required for simply running + under ACRN as a User VM. + + To compile as a module, choose M, the module will be called + acrn. If unsure, say N. |