[PATCH] rust: kbuild: support `-Cjump-tables=n` for Rust 1.93.0

[Miguel Ojeda <ojeda@kernel.org>]

Rust 1.93.0 (expected 2026-01-22) is stabilizing `-Zno-jump-tables`
[1][2] as `-Cjump-tables=n` [3].

Without this change, one would eventually see:

      RUSTC L rust/core.o
    error: unknown unstable option: `no-jump-tables`

Thus support the upcoming version.

Link: https://github.com/rust-lang/rust/issues/116592 [1]
Link: https://github.com/rust-lang/rust/pull/105812 [2]
Link: https://github.com/rust-lang/rust/pull/145974 [3]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 arch/loongarch/Makefile | 2 +-
 arch/x86/Makefile       | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index dc5bd3f1b8d2..96ca1a688984 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -109,7 +109,7 @@ 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
+KBUILD_RUSTFLAGS		+= $(if $(call rustc-min-version,109300),-Cjump-tables=n,-Zno-jump-tables) # keep compatibility with older compilers
 endif
 ifdef CONFIG_LTO_CLANG
 # The annotate-tablejump option can not be passed to LLVM backend when LTO is enabled.
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 4db7e4bf69f5..c60371db49d9 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -98,7 +98,7 @@ ifeq ($(CONFIG_X86_KERNEL_IBT),y)
 #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
 #
 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
-KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables
+KBUILD_RUSTFLAGS += -Zcf-protection=branch $(if $(call rustc-min-version,109300),-Cjump-tables=n,-Zno-jump-tables)
 else
 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
 endif

base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa
-- 
2.51.2