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| author | Tiezhu Yang <yangtiezhu@loongson.cn> | 2025-09-18 19:43:42 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-09-18 19:43:42 +0800 |
| commit | 74f8295c6fb8436bec9995baf6ba463151b6fb68 (patch) | |
| tree | 7bbe995d9fb75bcc1327efac91a1bf780f639166 | |
| parent | b15212824a01cb0b62f7b522f4ee334622cf982a (diff) | |
LoongArch: Handle jump tables options for RUST
When compiling with LLVM and CONFIG_RUST is set, there exist objtool
warnings in rust/core.o and rust/kernel.o, like this:
rust/core.o: warning: objtool:
_RNvXs1_NtNtCs5QSdWC790r4_4core5ascii10ascii_charNtB5_9AsciiCharNtNtB9_3fmt5Debug3fmt+0x54:
sibling call from callable instruction with modified stack frame
For this special case, the related object file shows that there is no
generated relocation section '.rela.discard.tablejump_annotate' for the
table jump instruction jirl, thus objtool can not know that what is the
actual destination address.
If rustc has the option "-Cllvm-args=--loongarch-annotate-tablejump",
pass the option to enable jump tables for objtool, otherwise it should
pass "-Zno-jump-tables" to keep compatibility with older rustc.
How to test:
$ rustup component add rust-src
$ make LLVM=1 rustavailable
$ make ARCH=loongarch LLVM=1 clean defconfig
$ scripts/config -d MODVERSIONS \
-e RUST -e SAMPLES -e SAMPLES_RUST \
-e SAMPLE_RUST_CONFIGFS -e SAMPLE_RUST_MINIMAL \
-e SAMPLE_RUST_MISC_DEVICE -e SAMPLE_RUST_PRINT \
-e SAMPLE_RUST_DMA -e SAMPLE_RUST_DRIVER_PCI \
-e SAMPLE_RUST_DRIVER_PLATFORM -e SAMPLE_RUST_DRIVER_FAUX \
-e SAMPLE_RUST_DRIVER_AUXILIARY -e SAMPLE_RUST_HOSTPROGS
$ make ARCH=loongarch LLVM=1 olddefconfig all
Cc: stable@vger.kernel.org
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://lore.kernel.org/rust-for-linux/CANiq72mNeCuPkCDrG2db3w=AX+O-zYrfprisDPmRac_qh65Dmg@mail.gmail.com/
Suggested-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
| -rw-r--r-- | arch/loongarch/Kconfig | 4 | ||||
| -rw-r--r-- | arch/loongarch/Makefile | 5 |
2 files changed, 9 insertions, 0 deletions
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index f0abc38c40ac..57933a717e92 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -298,6 +298,10 @@ config AS_HAS_LVZ_EXTENSION config CC_HAS_ANNOTATE_TABLEJUMP def_bool $(cc-option,-mannotate-tablejump) +config RUSTC_HAS_ANNOTATE_TABLEJUMP + depends on RUST + def_bool $(rustc-option,-Cllvm-args=--loongarch-annotate-tablejump) + menu "Kernel type and options" source "kernel/Kconfig.hz" diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile index 9d80af7f75c8..ae419e32f22e 100644 --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -106,6 +106,11 @@ KBUILD_CFLAGS += -mannotate-tablejump else KBUILD_CFLAGS += -fno-jump-tables # keep compatibility with older compilers endif +ifdef CONFIG_RUSTC_HAS_ANNOTATE_TABLEJUMP +KBUILD_RUSTFLAGS += -Cllvm-args=--loongarch-annotate-tablejump +else +KBUILD_RUSTFLAGS += -Zno-jump-tables # keep compatibility with older compilers +endif ifdef CONFIG_LTO_CLANG # The annotate-tablejump option can not be passed to LLVM backend when LTO is enabled. # Ensure it is aware of linker with LTO, '--loongarch-annotate-tablejump' also needs to |