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authorThomas Weißschuh <thomas.weissschuh@linutronix.de>2025-11-14 14:43:58 +0100
committerNicolas Schier <nsc@kernel.org>2025-11-14 20:20:35 +0100
commitdeab487e0f9b39ae4603e22d7d00908ebfc9753c (patch)
tree192c5044d2cd8191e53940bf27e98f43123a4927
parent80623f2c83d7de5c289d4240b8f4cef4103c51fc (diff)
kbuild: allow architectures to override CC_CAN_LINK
The generic test for CC_CAN_LINK assumes that all architectures use -m32 and -m64 to switch between 32-bit and 64-bit compilation. This is overly simplistic. Architectures may use other flags (-mabi, -m31, etc.) or may also require byte order handling (-mlittle-endian, -EL). Expressing all of the different possibilities will be very complicated and brittle. Instead allow architectures to supply their own logic which will be easy to understand and evolve. Both the boolean ARCH_HAS_CC_CAN_LINK and the string ARCH_USERFLAGS need to be implemented as kconfig does not allow the reuse of string options. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Nicolas Schier <nsc@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://patch.msgid.link/20251114-kbuild-userprogs-bits-v3-3-4dee0d74d439@linutronix.de Signed-off-by: Nicolas Schier <nsc@kernel.org>
-rw-r--r--Makefile13
-rw-r--r--init/Kconfig4
2 files changed, 15 insertions, 2 deletions
diff --git a/Makefile b/Makefile
index 96ca0f17d158..63f16b160668 100644
--- a/Makefile
+++ b/Makefile
@@ -1137,8 +1137,17 @@ ifneq ($(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS),)
LDFLAGS_vmlinux += --emit-relocs --discard-none
endif
-# Align the bit size of userspace programs with the kernel
-USERFLAGS_FROM_KERNEL := -m32 -m64 --target=%
+# Align the architecture of userspace programs with the kernel
+USERFLAGS_FROM_KERNEL := --target=%
+
+ifdef CONFIG_ARCH_USERFLAGS
+KBUILD_USERCFLAGS += $(CONFIG_ARCH_USERFLAGS)
+KBUILD_USERLDFLAGS += $(CONFIG_ARCH_USERFLAGS)
+else
+# If not overridden also inherit the bit size
+USERFLAGS_FROM_KERNEL += -m32 -m64
+endif
+
KBUILD_USERCFLAGS += $(filter $(USERFLAGS_FROM_KERNEL), $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
KBUILD_USERLDFLAGS += $(filter $(USERFLAGS_FROM_KERNEL), $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
diff --git a/init/Kconfig b/init/Kconfig
index 7b722e714d5c..4a2ae3cfbf26 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -82,8 +82,12 @@ config RUSTC_LLVM_VERSION
int
default $(rustc-llvm-version)
+config ARCH_HAS_CC_CAN_LINK
+ bool
+
config CC_CAN_LINK
bool
+ default ARCH_CC_CAN_LINK if ARCH_HAS_CC_CAN_LINK
default $(cc_can_link_user,$(m64-flag)) if 64BIT
default $(cc_can_link_user,$(m32-flag))