[PATCH v6 7/9] LoongArch: Enable jump table for objtool

From: Tiezhu Yang
Date: Mon Dec 16 2024 - 20:11:18 EST


For now, it is time to remove -fno-jump-tables to enable jump table for
objtool if the compiler has -mannotate-tablejump, otherwise it is better
to remain -fno-jump-tables to keep compatibility with older compilers.

Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
---
arch/loongarch/Kconfig | 3 +++
arch/loongarch/Makefile | 6 +++++-
2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index dae3a9104ca6..66980d847f4e 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -287,6 +287,9 @@ config AS_HAS_LBT_EXTENSION
config AS_HAS_LVZ_EXTENSION
def_bool $(as-instr,hvcl 0)

+config CC_HAS_ANNOTATE_TABLEJUMP
+ def_bool $(cc-option,-mannotate-tablejump)
+
menu "Kernel type and options"

source "kernel/Kconfig.hz"
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index 567bd122a9ee..0304eabbe606 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -101,7 +101,11 @@ KBUILD_AFLAGS += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)
KBUILD_CFLAGS += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)

ifdef CONFIG_OBJTOOL
-KBUILD_CFLAGS += -fno-jump-tables
+ifdef CONFIG_CC_HAS_ANNOTATE_TABLEJUMP
+KBUILD_CFLAGS += -mannotate-tablejump
+else
+KBUILD_CFLAGS += -fno-jump-tables # keep compatibility with older compilers
+endif
endif

KBUILD_RUSTFLAGS += --target=loongarch64-unknown-none-softfloat -Ccode-model=small
--
2.42.0