[PATCH v1 3/6] LoongArch: Enable jump table for objtool

From: Tiezhu Yang
Date: Tue Oct 15 2024 - 07:40:03 EST


For now, it can remove -fno-jump-tables and then enable jump table
for objtool if the compiler has option -mannotate-tablejump.

Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
---
arch/loongarch/Kconfig | 8 +++++++-
arch/loongarch/Makefile | 5 +----
2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index bb35c34f86d2..49ed776cb253 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -150,7 +150,7 @@ config LOONGARCH
select HAVE_LIVEPATCH
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
- select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB
+ select HAVE_OBJTOOL if TOOLCHAIN_SUPPORTS_OBJTOOL
select HAVE_PCI
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
@@ -284,6 +284,12 @@ 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)
+
+config TOOLCHAIN_SUPPORTS_OBJTOOL
+ def_bool AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB && CC_HAS_ANNOTATE_TABLEJUMP
+
menu "Kernel type and options"

source "kernel/Kconfig.hz"
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index ae3f80622f4c..69a3b4ae6c60 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -99,10 +99,7 @@ KBUILD_AFLAGS += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno
KBUILD_CFLAGS += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
KBUILD_AFLAGS += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
KBUILD_CFLAGS += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
-
-ifdef CONFIG_OBJTOOL
-KBUILD_CFLAGS += -fno-jump-tables
-endif
+KBUILD_CFLAGS += $(call cc-option,-mannotate-tablejump)

KBUILD_RUSTFLAGS += --target=loongarch64-unknown-none-softfloat
KBUILD_RUSTFLAGS_KERNEL += -Zdirect-access-external-data=yes
--
2.42.0