selftests/nolibc: add armthumb configuration

While nolibc does support ARM Thumb instructions,
that support was not tested specifically.

Add a new test configuration for it.

Tested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20250301-nolibc-armthumb-v1-2-d1f04abb5f6d@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

Author: t-8ch

tools/testing/selftests/nolibc/Makefile

@@ -47,6 +47,7 @@ XARCH_riscv      = riscv64
 XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH))
 
 # map from user input variants to their kernel supported architectures
+ARCH_armthumb    = arm
 ARCH_ppc         = powerpc
 ARCH_ppc64       = powerpc
 ARCH_ppc64le     = powerpc
@@ -63,6 +64,7 @@ IMAGE_x86_64     = arch/x86/boot/bzImage
 IMAGE_x86        = arch/x86/boot/bzImage
 IMAGE_arm64      = arch/arm64/boot/Image
 IMAGE_arm        = arch/arm/boot/zImage
+IMAGE_armthumb   = arch/arm/boot/zImage
 IMAGE_mips32le   = vmlinuz
 IMAGE_mips32be   = vmlinuz
 IMAGE_ppc        = vmlinux
@@ -83,6 +85,7 @@ DEFCONFIG_x86_64     = defconfig
 DEFCONFIG_x86        = defconfig
 DEFCONFIG_arm64      = defconfig
 DEFCONFIG_arm        = multi_v7_defconfig
+DEFCONFIG_armthumb   = multi_v7_defconfig
 DEFCONFIG_mips32le   = malta_defconfig
 DEFCONFIG_mips32be   = malta_defconfig generic/eb.config
 DEFCONFIG_ppc        = pmac32_defconfig
@@ -107,6 +110,7 @@ QEMU_ARCH_x86_64     = x86_64
 QEMU_ARCH_x86        = x86_64
 QEMU_ARCH_arm64      = aarch64
 QEMU_ARCH_arm        = arm
+QEMU_ARCH_armthumb   = arm
 QEMU_ARCH_mips32le   = mipsel  # works with malta_defconfig
 QEMU_ARCH_mips32be  = mips
 QEMU_ARCH_ppc        = ppc
@@ -136,6 +140,7 @@ QEMU_ARGS_x86_64     = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(
 QEMU_ARGS_x86        = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_arm64      = -M virt -cpu cortex-a53 -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_arm        = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_armthumb   = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_mips32le   = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_mips32be   = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_ppc        = -M g3beige -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
@@ -161,6 +166,7 @@ endif
 
 CFLAGS_i386 = $(call cc-option,-m32)
 CFLAGS_arm = -marm
+CFLAGS_armthumb = -mthumb -march=armv6t2
 CFLAGS_ppc = -m32 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
 CFLAGS_ppc64 = -m64 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
 CFLAGS_ppc64le = -m64 -mlittle-endian -mno-vsx $(call cc-option,-mabi=elfv2)

tools/testing/selftests/nolibc/run-tests.sh

@@ -19,7 +19,7 @@ werror=1
 llvm=
 all_archs=(
 	i386 x86_64
-	arm64 arm
+	arm64 arm armthumb
 	mips32le mips32be
 	ppc ppc64 ppc64le
 	riscv32 riscv64
@@ -103,6 +103,7 @@ fi
 crosstool_arch() {
 	case "$1" in
 	arm64) echo aarch64;;
+	armthumb) echo arm;;
 	ppc) echo powerpc;;
 	ppc64) echo powerpc64;;
 	ppc64le) echo powerpc64;;
@@ -116,7 +117,7 @@ crosstool_arch() {
 
 crosstool_abi() {
 	case "$1" in
-	arm) echo linux-gnueabi;;
+	arm | armthumb) echo linux-gnueabi;;
 	*) echo linux;;
 	esac
 }