[tip: objtool/core] LoongArch: Enable jump table for objtool

[tip-bot2 for Tiezhu Yang]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     e20ab7d454ee8d1e0e8b9ff73a7c87e84c666b2f
Gitweb:        https://git.kernel.org/tip/e20ab7d454ee8d1e0e8b9ff73a7c87e84c666b2f
Author:        Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
AuthorDate:    Tue, 17 Dec 2024 09:09:03 +08:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Wed, 12 Mar 2025 15:43:39 -07:00

LoongArch: Enable jump table for objtool

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>
Link: https://lore.kernel.org/r/20241217010905.13054-8-yangtiezhu@xxxxxxxxxxx
Acked-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 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 2b8bd27..15aaa2e 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -291,6 +291,9 @@ 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 567bd12..0304eab 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