diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index a1f55fb..dceec0e 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -29,6 +29,7 @@ all_files := \
 		compiler.h \
 		crt.h \
 		ctype.h \
+		dirent.h \
 		errno.h \
 		nolibc.h \
 		signal.h \
diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
index 1791a8c..753a8ed 100644
--- a/tools/include/nolibc/arch-mips.h
+++ b/tools/include/nolibc/arch-mips.h
@@ -179,6 +179,7 @@
 })
 
 /* startup code, note that it's called __start on MIPS */
+void __start(void);
 void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector __start(void)
 {
 	__asm__ volatile (
diff --git a/tools/include/nolibc/arch-s390.h b/tools/include/nolibc/arch-s390.h
index f9ab83a..df4c3cc 100644
--- a/tools/include/nolibc/arch-s390.h
+++ b/tools/include/nolibc/arch-s390.h
@@ -5,8 +5,8 @@
 
 #ifndef _NOLIBC_ARCH_S390_H
 #define _NOLIBC_ARCH_S390_H
-#include <asm/signal.h>
-#include <asm/unistd.h>
+#include <linux/signal.h>
+#include <linux/unistd.h>
 
 #include "compiler.h"
 #include "crt.h"
@@ -143,8 +143,13 @@
 void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
+#ifdef __s390x__
 		"lgr	%r2, %r15\n"          /* save stack pointer to %r2, as arg1 of _start_c */
 		"aghi	%r15, -160\n"         /* allocate new stackframe                        */
+#else
+		"lr	%r2, %r15\n"
+		"ahi	%r15, -96\n"
+#endif
 		"xc	0(8,%r15), 0(%r15)\n" /* clear backchain                                */
 		"brasl	%r14, _start_c\n"     /* transfer to c runtime                          */
 	);
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index c8f4e5d..8a2c143 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -29,7 +29,7 @@
 #include "arch-powerpc.h"
 #elif defined(__riscv)
 #include "arch-riscv.h"
-#elif defined(__s390x__)
+#elif defined(__s390x__) || defined(__s390__)
 #include "arch-s390.h"
 #elif defined(__loongarch__)
 #include "arch-loongarch.h"
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
index bbcd5fd..c4b1010 100644
--- a/tools/include/nolibc/crt.h
+++ b/tools/include/nolibc/crt.h
@@ -10,6 +10,7 @@
 char **environ __attribute__((weak));
 const unsigned long *_auxv __attribute__((weak));
 
+void _start(void);
 static void __stack_chk_init(void);
 static void exit(int);
 
@@ -22,6 +23,7 @@ extern void (*const __init_array_end[])(int, char **, char**) __attribute__((wea
 extern void (*const __fini_array_start[])(void) __attribute__((weak));
 extern void (*const __fini_array_end[])(void) __attribute__((weak));
 
+void _start_c(long *sp);
 __attribute__((weak,used))
 void _start_c(long *sp)
 {
diff --git a/tools/include/nolibc/dirent.h b/tools/include/nolibc/dirent.h
new file mode 100644
index 0000000..c5c30d0
--- /dev/null
+++ b/tools/include/nolibc/dirent.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Directory access for NOLIBC
+ * Copyright (C) 2025 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_DIRENT_H
+#define _NOLIBC_DIRENT_H
+
+#include "stdint.h"
+#include "types.h"
+
+#include <linux/limits.h>
+
+struct dirent {
+	ino_t	d_ino;
+	char	d_name[NAME_MAX + 1];
+};
+
+/* See comment of FILE in stdio.h */
+typedef struct {
+	char dummy[1];
+} DIR;
+
+static __attribute__((unused))
+DIR *fdopendir(int fd)
+{
+	if (fd < 0) {
+		SET_ERRNO(EBADF);
+		return NULL;
+	}
+	return (DIR *)(intptr_t)~fd;
+}
+
+static __attribute__((unused))
+DIR *opendir(const char *name)
+{
+	int fd;
+
+	fd = open(name, O_RDONLY);
+	if (fd == -1)
+		return NULL;
+	return fdopendir(fd);
+}
+
+static __attribute__((unused))
+int closedir(DIR *dirp)
+{
+	intptr_t i = (intptr_t)dirp;
+
+	if (i >= 0) {
+		SET_ERRNO(EBADF);
+		return -1;
+	}
+	return close(~i);
+}
+
+static __attribute__((unused))
+int readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
+{
+	char buf[sizeof(struct linux_dirent64) + NAME_MAX + 1];
+	struct linux_dirent64 *ldir = (void *)buf;
+	intptr_t i = (intptr_t)dirp;
+	int fd, ret;
+
+	if (i >= 0)
+		return EBADF;
+
+	fd = ~i;
+
+	ret = sys_getdents64(fd, ldir, sizeof(buf));
+	if (ret < 0)
+		return -ret;
+	if (ret == 0) {
+		*result = NULL;
+		return 0;
+	}
+
+	/*
+	 * getdents64() returns as many entries as fit the buffer.
+	 * readdir() can only return one entry at a time.
+	 * Make sure the non-returned ones are not skipped.
+	 */
+	ret = lseek(fd, ldir->d_off, SEEK_SET);
+	if (ret == -1)
+		return errno;
+
+	entry->d_ino = ldir->d_ino;
+	/* the destination should always be big enough */
+	strlcpy(entry->d_name, ldir->d_name, sizeof(entry->d_name));
+	*result = entry;
+	return 0;
+}
+
+/* make sure to include all global symbols */
+#include "nolibc.h"
+
+#endif /* _NOLIBC_DIRENT_H */
diff --git a/tools/include/nolibc/errno.h b/tools/include/nolibc/errno.h
index a44486f..1d8d803 100644
--- a/tools/include/nolibc/errno.h
+++ b/tools/include/nolibc/errno.h
@@ -7,7 +7,7 @@
 #ifndef _NOLIBC_ERRNO_H
 #define _NOLIBC_ERRNO_H
 
-#include <asm/errno.h>
+#include <linux/errno.h>
 
 #ifndef NOLIBC_IGNORE_ERRNO
 #define SET_ERRNO(v) do { errno = (v); } while (0)
diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
index 92436b1..7087240 100644
--- a/tools/include/nolibc/nolibc.h
+++ b/tools/include/nolibc/nolibc.h
@@ -31,8 +31,7 @@
  *   - The third level is the libc call definition. It exposes the lower raw
  *     sys_<name>() calls in a way that looks like what a libc usually does,
  *     takes care of specific input values, and of setting errno upon error.
- *     There can be minor variations compared to standard libc calls. For
- *     example the open() call always takes 3 args here.
+ *     There can be minor variations compared to standard libc calls.
  *
  * The errno variable is declared static and unused. This way it can be
  * optimized away if not used. However this means that a program made of
@@ -105,6 +104,7 @@
 #include "string.h"
 #include "time.h"
 #include "stackprotector.h"
+#include "dirent.h"
 
 /* Used by programs to avoid std includes */
 #define NOLIBC
diff --git a/tools/include/nolibc/signal.h b/tools/include/nolibc/signal.h
index 1375522..cdcc590 100644
--- a/tools/include/nolibc/signal.h
+++ b/tools/include/nolibc/signal.h
@@ -13,6 +13,7 @@
 #include "sys.h"
 
 /* This one is not marked static as it's needed by libgcc for divide by zero */
+int raise(int signal);
 __attribute__((weak,unused,section(".text.nolibc_raise")))
 int raise(int signal)
 {
diff --git a/tools/include/nolibc/stackprotector.h b/tools/include/nolibc/stackprotector.h
index 1d0d525..c71a2c2 100644
--- a/tools/include/nolibc/stackprotector.h
+++ b/tools/include/nolibc/stackprotector.h
@@ -18,6 +18,7 @@
  * triggering stack protector errors themselves
  */
 
+void __stack_chk_fail(void);
 __attribute__((weak,used,noreturn,section(".text.nolibc_stack_chk")))
 void __stack_chk_fail(void)
 {
@@ -28,6 +29,7 @@ void __stack_chk_fail(void)
 	for (;;);
 }
 
+void __stack_chk_fail_local(void);
 __attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
 void __stack_chk_fail_local(void)
 {
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index 3892034..a403351 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -350,6 +350,104 @@ int printf(const char *fmt, ...)
 }
 
 static __attribute__((unused))
+int vsscanf(const char *str, const char *format, va_list args)
+{
+	uintmax_t uval;
+	intmax_t ival;
+	int base;
+	char *endptr;
+	int matches;
+	int lpref;
+
+	matches = 0;
+
+	while (1) {
+		if (*format == '%') {
+			/* start of pattern */
+			lpref = 0;
+			format++;
+
+			if (*format == 'l') {
+				/* same as in printf() */
+				lpref = 1;
+				format++;
+				if (*format == 'l') {
+					lpref = 2;
+					format++;
+				}
+			}
+
+			if (*format == '%') {
+				/* literal % */
+				if ('%' != *str)
+					goto done;
+				str++;
+				format++;
+				continue;
+			} else if (*format == 'd') {
+				ival = strtoll(str, &endptr, 10);
+				if (lpref == 0)
+					*va_arg(args, int *) = ival;
+				else if (lpref == 1)
+					*va_arg(args, long *) = ival;
+				else if (lpref == 2)
+					*va_arg(args, long long *) = ival;
+			} else if (*format == 'u' || *format == 'x' || *format == 'X') {
+				base = *format == 'u' ? 10 : 16;
+				uval = strtoull(str, &endptr, base);
+				if (lpref == 0)
+					*va_arg(args, unsigned int *) = uval;
+				else if (lpref == 1)
+					*va_arg(args, unsigned long *) = uval;
+				else if (lpref == 2)
+					*va_arg(args, unsigned long long *) = uval;
+			} else if (*format == 'p') {
+				*va_arg(args, void **) = (void *)strtoul(str, &endptr, 16);
+			} else {
+				SET_ERRNO(EILSEQ);
+				goto done;
+			}
+
+			format++;
+			str = endptr;
+			matches++;
+
+		} else if (*format == '\0') {
+			goto done;
+		} else if (isspace(*format)) {
+			/* skip spaces in format and str */
+			while (isspace(*format))
+				format++;
+			while (isspace(*str))
+				str++;
+		} else if (*format == *str) {
+			/* literal match */
+			format++;
+			str++;
+		} else {
+			if (!matches)
+				matches = EOF;
+			goto done;
+		}
+	}
+
+done:
+	return matches;
+}
+
+static __attribute__((unused, format(scanf, 2, 3)))
+int sscanf(const char *str, const char *format, ...)
+{
+	va_list args;
+	int ret;
+
+	va_start(args, format);
+	ret = vsscanf(str, format, args);
+	va_end(args);
+	return ret;
+}
+
+static __attribute__((unused))
 void perror(const char *msg)
 {
 	fprintf(stderr, "%s%serrno=%d\n", (msg && *msg) ? msg : "", (msg && *msg) ? ": " : "", errno);
diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h
index 75aa273..86ad378 100644
--- a/tools/include/nolibc/stdlib.h
+++ b/tools/include/nolibc/stdlib.h
@@ -30,6 +30,7 @@ static __attribute__((unused)) char itoa_buffer[21];
  */
 
 /* must be exported, as it's used by libgcc for various divide functions */
+void abort(void);
 __attribute__((weak,unused,noreturn,section(".text.nolibc_abort")))
 void abort(void)
 {
diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
index 9ec9c24..ba84ab7 100644
--- a/tools/include/nolibc/string.h
+++ b/tools/include/nolibc/string.h
@@ -32,6 +32,7 @@ int memcmp(const void *s1, const void *s2, size_t n)
 /* might be ignored by the compiler without -ffreestanding, then found as
  * missing.
  */
+void *memmove(void *dst, const void *src, size_t len);
 __attribute__((weak,unused,section(".text.nolibc_memmove")))
 void *memmove(void *dst, const void *src, size_t len)
 {
@@ -56,6 +57,7 @@ void *memmove(void *dst, const void *src, size_t len)
 
 #ifndef NOLIBC_ARCH_HAS_MEMCPY
 /* must be exported, as it's used by libgcc on ARM */
+void *memcpy(void *dst, const void *src, size_t len);
 __attribute__((weak,unused,section(".text.nolibc_memcpy")))
 void *memcpy(void *dst, const void *src, size_t len)
 {
@@ -73,6 +75,7 @@ void *memcpy(void *dst, const void *src, size_t len)
 /* might be ignored by the compiler without -ffreestanding, then found as
  * missing.
  */
+void *memset(void *dst, int b, size_t len);
 __attribute__((weak,unused,section(".text.nolibc_memset")))
 void *memset(void *dst, int b, size_t len)
 {
@@ -124,6 +127,7 @@ char *strcpy(char *dst, const char *src)
  * thus itself, hence the asm() statement below that's meant to disable this
  * confusing practice.
  */
+size_t strlen(const char *str);
 __attribute__((weak,unused,section(".text.nolibc_strlen")))
 size_t strlen(const char *str)
 {
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index d4a5c23..08c1c07 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -10,10 +10,10 @@
 #include "std.h"
 
 /* system includes */
-#include <asm/unistd.h>
-#include <asm/signal.h>  /* for SIGCHLD */
-#include <asm/ioctls.h>
-#include <asm/mman.h>
+#include <linux/unistd.h>
+#include <linux/signal.h>  /* for SIGCHLD */
+#include <linux/termios.h>
+#include <linux/mman.h>
 #include <linux/fs.h>
 #include <linux/loop.h>
 #include <linux/time.h>
@@ -23,7 +23,6 @@
 #include <linux/prctl.h>
 #include <linux/resource.h>
 #include <linux/utsname.h>
-#include <linux/signal.h>
 
 #include "arch.h"
 #include "errno.h"
@@ -532,20 +531,16 @@ uid_t getuid(void)
 
 
 /*
- * int ioctl(int fd, unsigned long req, void *value);
+ * int ioctl(int fd, unsigned long cmd, ... arg);
  */
 
 static __attribute__((unused))
-int sys_ioctl(int fd, unsigned long req, void *value)
+long sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 {
-	return my_syscall3(__NR_ioctl, fd, req, value);
+	return my_syscall3(__NR_ioctl, fd, cmd, arg);
 }
 
-static __attribute__((unused))
-int ioctl(int fd, unsigned long req, void *value)
-{
-	return __sysret(sys_ioctl(fd, req, value));
-}
+#define ioctl(fd, cmd, arg) __sysret(sys_ioctl(fd, cmd, (unsigned long)(arg)))
 
 /*
  * int kill(pid_t pid, int signal);
@@ -602,9 +597,36 @@ off_t sys_lseek(int fd, off_t offset, int whence)
 }
 
 static __attribute__((unused))
+int sys_llseek(int fd, unsigned long offset_high, unsigned long offset_low,
+	       __kernel_loff_t *result, int whence)
+{
+#ifdef __NR_llseek
+	return my_syscall5(__NR_llseek, fd, offset_high, offset_low, result, whence);
+#else
+	return __nolibc_enosys(__func__, fd, offset_high, offset_low, result, whence);
+#endif
+}
+
+static __attribute__((unused))
 off_t lseek(int fd, off_t offset, int whence)
 {
-	return __sysret(sys_lseek(fd, offset, whence));
+	__kernel_loff_t loff = 0;
+	off_t result;
+	int ret;
+
+	result = sys_lseek(fd, offset, whence);
+	if (result == -ENOSYS) {
+		/* Only exists on 32bit where nolibc off_t is also 32bit */
+		ret = sys_llseek(fd, 0, offset, &loff, whence);
+		if (ret < 0)
+			result = ret;
+		else if (loff != (off_t)loff)
+			result = -EOVERFLOW;
+		else
+			result = loff;
+	}
+
+	return __sysret(result);
 }
 
 
@@ -742,6 +764,31 @@ int mount(const char *src, const char *tgt,
 	return __sysret(sys_mount(src, tgt, fst, flags, data));
 }
 
+/*
+ * int openat(int dirfd, const char *path, int flags[, mode_t mode]);
+ */
+
+static __attribute__((unused))
+int sys_openat(int dirfd, const char *path, int flags, mode_t mode)
+{
+	return my_syscall4(__NR_openat, dirfd, path, flags, mode);
+}
+
+static __attribute__((unused))
+int openat(int dirfd, const char *path, int flags, ...)
+{
+	mode_t mode = 0;
+
+	if (flags & O_CREAT) {
+		va_list args;
+
+		va_start(args, flags);
+		mode = va_arg(args, mode_t);
+		va_end(args);
+	}
+
+	return __sysret(sys_openat(dirfd, path, flags, mode));
+}
 
 /*
  * int open(const char *path, int flags[, mode_t mode]);
@@ -750,13 +797,7 @@ int mount(const char *src, const char *tgt,
 static __attribute__((unused))
 int sys_open(const char *path, int flags, mode_t mode)
 {
-#ifdef __NR_openat
 	return my_syscall4(__NR_openat, AT_FDCWD, path, flags, mode);
-#elif defined(__NR_open)
-	return my_syscall3(__NR_open, path, flags, mode);
-#else
-	return __nolibc_enosys(__func__, path, flags, mode);
-#endif
 }
 
 static __attribute__((unused))
@@ -768,7 +809,7 @@ int open(const char *path, int flags, ...)
 		va_list args;
 
 		va_start(args, flags);
-		mode = va_arg(args, int);
+		mode = va_arg(args, mode_t);
 		va_end(args);
 	}
 
diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index cdf91b0..c3b6d26 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -444,10 +444,6 @@ static inline __noreturn __printf(1, 2) void ksft_exit_skip(const char *msg, ...
 static inline int ksft_min_kernel_version(unsigned int min_major,
 					  unsigned int min_minor)
 {
-#ifdef NOLIBC
-	ksft_print_msg("NOLIBC: Can't check kernel version: Function not implemented\n");
-	return 0;
-#else
 	unsigned int major, minor;
 	struct utsname info;
 
@@ -455,7 +451,6 @@ static inline int ksft_min_kernel_version(unsigned int min_major,
 		ksft_exit_fail_msg("Can't parse kernel version\n");
 
 	return major > min_major || (major == min_major && minor >= min_minor);
-#endif
 }
 
 #endif /* __KSELFTEST_H */
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 7d14a7c..58bcbbd 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/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
@@ -54,6 +55,7 @@ ARCH_mips32le    = mips
 ARCH_mips32be    = mips
 ARCH_riscv32     = riscv
 ARCH_riscv64     = riscv
+ARCH_s390x       = s390
 ARCH            := $(or $(ARCH_$(XARCH)),$(XARCH))
 
 # kernel image names by architecture
@@ -62,6 +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
@@ -70,6 +73,7 @@ IMAGE_ppc64le    = arch/powerpc/boot/zImage
 IMAGE_riscv      = arch/riscv/boot/Image
 IMAGE_riscv32    = arch/riscv/boot/Image
 IMAGE_riscv64    = arch/riscv/boot/Image
+IMAGE_s390x      = arch/s390/boot/bzImage
 IMAGE_s390       = arch/s390/boot/bzImage
 IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
 IMAGE            = $(objtree)/$(IMAGE_$(XARCH))
@@ -81,19 +85,20 @@ 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
+DEFCONFIG_mips32be   = malta_defconfig generic/eb.config
 DEFCONFIG_ppc        = pmac32_defconfig
 DEFCONFIG_ppc64      = powernv_be_defconfig
 DEFCONFIG_ppc64le    = powernv_defconfig
 DEFCONFIG_riscv      = defconfig
 DEFCONFIG_riscv32    = rv32_defconfig
 DEFCONFIG_riscv64    = defconfig
-DEFCONFIG_s390       = defconfig
+DEFCONFIG_s390x      = defconfig
+DEFCONFIG_s390       = defconfig compat.config
 DEFCONFIG_loongarch  = defconfig
 DEFCONFIG            = $(DEFCONFIG_$(XARCH))
 
-EXTRACONFIG_mips32be = -d CONFIG_CPU_LITTLE_ENDIAN -e CONFIG_CPU_BIG_ENDIAN
 EXTRACONFIG           = $(EXTRACONFIG_$(XARCH))
 
 # optional tests to run (default = all)
@@ -105,6 +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
@@ -113,6 +119,7 @@ QEMU_ARCH_ppc64le    = ppc64
 QEMU_ARCH_riscv      = riscv64
 QEMU_ARCH_riscv32    = riscv32
 QEMU_ARCH_riscv64    = riscv64
+QEMU_ARCH_s390x      = s390x
 QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
 QEMU_ARCH            = $(QEMU_ARCH_$(XARCH))
@@ -133,6 +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=%)"
@@ -141,6 +149,7 @@ QEMU_ARGS_ppc64le    = -M powernv -append "console=hvc0 panic=-1 $(TEST:%=NOLIBC
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv32    = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv64    = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_s390x      = -M s390-ccw-virtio -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS            = -m 1G $(QEMU_ARGS_$(XARCH)) $(QEMU_ARGS_BIOS) $(QEMU_ARGS_EXTRA)
@@ -156,15 +165,18 @@ Q=@
 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)
-CFLAGS_s390 = -m64
+CFLAGS_s390x = -m64
+CFLAGS_s390 = -m31
 CFLAGS_mips32le = -EL -mabi=32 -fPIC
 CFLAGS_mips32be = -EB -mabi=32
 CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
 CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -W -Wall -Wextra \
-		$(call cc-option,-fno-stack-protector) \
+		$(call cc-option,-fno-stack-protector) $(call cc-option,-Wmissing-prototypes) \
 		$(CFLAGS_$(XARCH)) $(CFLAGS_STACKPROTECTOR) $(CFLAGS_EXTRA)
 LDFLAGS :=
 
@@ -220,7 +232,7 @@ all: run
 
 sysroot: sysroot/$(ARCH)/include
 
-sysroot/$(ARCH)/include:
+sysroot/$(ARCH)/include: | defconfig
 	$(Q)rm -rf sysroot/$(ARCH) sysroot/sysroot
 	$(QUIET_MKDIR)mkdir -p sysroot
 	$(Q)$(MAKE) -C $(srctree) outputmakefile
@@ -264,16 +276,16 @@ initramfs: nolibc-test
 	$(Q)cp nolibc-test initramfs/init
 
 defconfig:
-	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) mrproper $(DEFCONFIG) prepare
+	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(DEFCONFIG)
 	$(Q)if [ -n "$(EXTRACONFIG)" ]; then \
 		$(srctree)/scripts/config --file $(objtree)/.config $(EXTRACONFIG); \
 		$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) olddefconfig < /dev/null; \
 	fi
 
-kernel:
+kernel: | defconfig
 	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(IMAGE_NAME) < /dev/null
 
-kernel-standalone: initramfs
+kernel-standalone: initramfs | defconfig
 	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(IMAGE_NAME) CONFIG_INITRAMFS_SOURCE=$(CURDIR)/initramfs < /dev/null
 
 # run the tests after building the kernel
diff --git a/tools/testing/selftests/nolibc/nolibc-test-linkage.c b/tools/testing/selftests/nolibc/nolibc-test-linkage.c
index 5ff4c8a..a7ca832 100644
--- a/tools/testing/selftests/nolibc/nolibc-test-linkage.c
+++ b/tools/testing/selftests/nolibc/nolibc-test-linkage.c
@@ -11,16 +11,16 @@ void *linkage_test_errno_addr(void)
 	return &errno;
 }
 
-int linkage_test_constructor_test_value;
+int linkage_test_constructor_test_value = 0;
 
 __attribute__((constructor))
 static void constructor1(void)
 {
-	linkage_test_constructor_test_value = 2;
+	linkage_test_constructor_test_value |= 1 << 0;
 }
 
 __attribute__((constructor))
 static void constructor2(void)
 {
-	linkage_test_constructor_test_value *= 3;
+	linkage_test_constructor_test_value |= 1 << 1;
 }
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 0e0e3b4..5884a89 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -43,6 +43,8 @@
 #endif
 #endif
 
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+
 #include "nolibc-test-linkage.h"
 
 /* for the type of int_fast16_t and int_fast32_t, musl differs from glibc and nolibc */
@@ -690,14 +692,14 @@ int expect_strtox(int llen, void *func, const char *input, int base, intmax_t ex
 __attribute__((constructor))
 static void constructor1(void)
 {
-	constructor_test_value = 1;
+	constructor_test_value |= 1 << 0;
 }
 
 __attribute__((constructor))
 static void constructor2(int argc, char **argv, char **envp)
 {
 	if (argc && argv && envp)
-		constructor_test_value *= 2;
+		constructor_test_value |= 1 << 1;
 }
 
 int run_startup(int min, int max)
@@ -736,9 +738,9 @@ int run_startup(int min, int max)
 		CASE_TEST(environ_HOME);     EXPECT_PTRNZ(1, getenv("HOME")); break;
 		CASE_TEST(auxv_addr);        EXPECT_PTRGT(test_auxv != (void *)-1, test_auxv, brk); break;
 		CASE_TEST(auxv_AT_UID);      EXPECT_EQ(1, getauxval(AT_UID), getuid()); break;
-		CASE_TEST(constructor);      EXPECT_EQ(1, constructor_test_value, 2); break;
+		CASE_TEST(constructor);      EXPECT_EQ(is_nolibc, constructor_test_value, 0x3); break;
 		CASE_TEST(linkage_errno);    EXPECT_PTREQ(1, linkage_test_errno_addr(), &errno); break;
-		CASE_TEST(linkage_constr);   EXPECT_EQ(1, linkage_test_constructor_test_value, 6); break;
+		CASE_TEST(linkage_constr);   EXPECT_EQ(1, linkage_test_constructor_test_value, 0x3); break;
 		case __LINE__:
 			return ret; /* must be last */
 		/* note: do not set any defaults so as to permit holes above */
@@ -767,6 +769,44 @@ int test_getdents64(const char *dir)
 	return ret;
 }
 
+static int test_dirent(void)
+{
+	int comm = 0, cmdline = 0;
+	struct dirent dirent, *result;
+	DIR *dir;
+	int ret;
+
+	dir = opendir("/proc/self");
+	if (!dir)
+		return 1;
+
+	while (1) {
+		errno = 0;
+		ret = readdir_r(dir, &dirent, &result);
+		if (ret != 0)
+			return 1;
+		if (!result)
+			break;
+
+		if (strcmp(dirent.d_name, "comm") == 0)
+			comm++;
+		else if (strcmp(dirent.d_name, "cmdline") == 0)
+			cmdline++;
+	}
+
+	if (errno)
+		return 1;
+
+	ret = closedir(dir);
+	if (ret)
+		return 1;
+
+	if (comm != 1 || cmdline != 1)
+		return 1;
+
+	return 0;
+}
+
 int test_getpagesize(void)
 {
 	int x = getpagesize();
@@ -988,6 +1028,22 @@ int test_rlimit(void)
 	return 0;
 }
 
+int test_openat(void)
+{
+	int dev, null;
+
+	dev = openat(AT_FDCWD, "/dev", O_DIRECTORY);
+	if (dev < 0)
+		return -1;
+
+	null = openat(dev, "null", O_RDONLY);
+	close(dev);
+	if (null < 0)
+		return -1;
+
+	close(null);
+	return 0;
+}
 
 /* Run syscall tests between IDs <min> and <max>.
  * Return 0 on success, non-zero on failure.
@@ -1059,6 +1115,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(fork);              EXPECT_SYSZR(1, test_fork()); break;
 		CASE_TEST(getdents64_root);   EXPECT_SYSNE(1, test_getdents64("/"), -1); break;
 		CASE_TEST(getdents64_null);   EXPECT_SYSER(1, test_getdents64("/dev/null"), -1, ENOTDIR); break;
+		CASE_TEST(directories);       EXPECT_SYSZR(proc, test_dirent()); break;
 		CASE_TEST(gettimeofday_tv);   EXPECT_SYSZR(1, gettimeofday(&tv, NULL)); break;
 		CASE_TEST(gettimeofday_tv_tz);EXPECT_SYSZR(1, gettimeofday(&tv, &tz)); break;
 		CASE_TEST(getpagesize);       EXPECT_SYSZR(1, test_getpagesize()); break;
@@ -1073,8 +1130,9 @@ int run_syscall(int min, int max)
 		CASE_TEST(mmap_bad);          EXPECT_PTRER(1, mmap(NULL, 0, PROT_READ, MAP_PRIVATE, 0, 0), MAP_FAILED, EINVAL); break;
 		CASE_TEST(munmap_bad);        EXPECT_SYSER(1, munmap(NULL, 0), -1, EINVAL); break;
 		CASE_TEST(mmap_munmap_good);  EXPECT_SYSZR(1, test_mmap_munmap()); break;
-		CASE_TEST(open_tty);          EXPECT_SYSNE(1, tmp = open("/dev/null", 0), -1); if (tmp != -1) close(tmp); break;
-		CASE_TEST(open_blah);         EXPECT_SYSER(1, tmp = open("/proc/self/blah", 0), -1, ENOENT); if (tmp != -1) close(tmp); break;
+		CASE_TEST(open_tty);          EXPECT_SYSNE(1, tmp = open("/dev/null", O_RDONLY), -1); if (tmp != -1) close(tmp); break;
+		CASE_TEST(open_blah);         EXPECT_SYSER(1, tmp = open("/proc/self/blah", O_RDONLY), -1, ENOENT); if (tmp != -1) close(tmp); break;
+		CASE_TEST(openat_dir);        EXPECT_SYSZR(1, test_openat()); break;
 		CASE_TEST(pipe);              EXPECT_SYSZR(1, test_pipe()); break;
 		CASE_TEST(poll_null);         EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
 		CASE_TEST(poll_stdout);       EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break;
@@ -1284,6 +1342,73 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
 	return ret;
 }
 
+static int test_scanf(void)
+{
+	unsigned long long ull;
+	unsigned long ul;
+	unsigned int u;
+	long long ll;
+	long l;
+	void *p;
+	int i;
+
+	/* return __LINE__ to point to the specific failure */
+
+	/* test EOF */
+	if (sscanf("", "foo") != EOF)
+		return __LINE__;
+
+	/* test simple literal without placeholder */
+	if (sscanf("foo", "foo") != 0)
+		return __LINE__;
+
+	/* test single placeholder */
+	if (sscanf("123", "%d", &i) != 1)
+		return __LINE__;
+
+	if (i != 123)
+		return __LINE__;
+
+	/* test multiple place holders and separators */
+	if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
+		return __LINE__;
+
+	if (i != 123)
+		return __LINE__;
+
+	if (u != 456)
+		return __LINE__;
+
+	if (p != (void *)0x90)
+		return __LINE__;
+
+	/* test space handling */
+	if (sscanf("a    b1", "a b%d", &i) != 1)
+		return __LINE__;
+
+	if (i != 1)
+		return __LINE__;
+
+	/* test literal percent */
+	if (sscanf("a%1", "a%%%d", &i) != 1)
+		return __LINE__;
+
+	if (i != 1)
+		return __LINE__;
+
+	/* test stdint.h types */
+	if (sscanf("1|2|3|4|5|6",
+		   "%d|%ld|%lld|%u|%lu|%llu",
+		   &i, &l, &ll, &u, &ul, &ull) != 6)
+		return __LINE__;
+
+	if (i != 1 || l != 2 || ll != 3 ||
+	    u != 4 || ul != 5 || ull != 6)
+		return __LINE__;
+
+	return 0;
+}
+
 static int run_vfprintf(int min, int max)
 {
 	int test;
@@ -1305,6 +1430,7 @@ static int run_vfprintf(int min, int max)
 		CASE_TEST(char);         EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
 		CASE_TEST(hex);          EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
 		CASE_TEST(pointer);      EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
+		CASE_TEST(scanf);        EXPECT_ZR(1, test_scanf()); break;
 		case __LINE__:
 			return ret; /* must be last */
 		/* note: do not set any defaults so as to permit holes above */
diff --git a/tools/testing/selftests/nolibc/run-tests.sh b/tools/testing/selftests/nolibc/run-tests.sh
index 9c5160c..0299a09 100755
--- a/tools/testing/selftests/nolibc/run-tests.sh
+++ b/tools/testing/selftests/nolibc/run-tests.sh
@@ -17,7 +17,16 @@ perform_download=0
 test_mode=system
 werror=1
 llvm=
-archs="i386 x86_64 arm64 arm mips32le mips32be ppc ppc64 ppc64le riscv32 riscv64 s390 loongarch"
+all_archs=(
+	i386 x86_64
+	arm64 arm armthumb
+	mips32le mips32be
+	ppc ppc64 ppc64le
+	riscv32 riscv64
+	s390x s390
+	loongarch
+)
+archs="${all_archs[@]}"
 
 TEMP=$(getopt -o 'j:d:c:b:a:m:pelh' -n "$0" -- "$@")
 
@@ -94,19 +103,21 @@ fi
 crosstool_arch() {
 	case "$1" in
 	arm64) echo aarch64;;
+	armthumb) echo arm;;
 	ppc) echo powerpc;;
 	ppc64) echo powerpc64;;
 	ppc64le) echo powerpc64;;
 	riscv) echo riscv64;;
 	loongarch) echo loongarch64;;
 	mips*) echo mips;;
+	s390*) echo s390;;
 	*) echo "$1";;
 	esac
 }
 
 crosstool_abi() {
 	case "$1" in
-	arm) echo linux-gnueabi;;
+	arm | armthumb) echo linux-gnueabi;;
 	*) echo linux;;
 	esac
 }
@@ -157,10 +168,6 @@ test_arch() {
 	fi
 	MAKE=(make -j"${nproc}" XARCH="${arch}" CROSS_COMPILE="${cross_compile}" LLVM="${llvm}" O="${build_dir}")
 
-	mkdir -p "$build_dir"
-	if [ "$test_mode" = "system" ] && [ ! -f "${build_dir}/.config" ]; then
-		swallow_output "${MAKE[@]}" defconfig
-	fi
 	case "$test_mode" in
 		'system')
 			test_target=run
@@ -173,6 +180,13 @@ test_arch() {
 			exit 1
 	esac
 	printf '%-15s' "$arch:"
+	if [ "$arch" = "s390" ] && ([ "$llvm" = "1" ] || [ "$test_mode" = "user" ]); then
+		echo "Unsupported configuration"
+		return
+	fi
+
+	mkdir -p "$build_dir"
+	swallow_output "${MAKE[@]}" defconfig
 	swallow_output "${MAKE[@]}" CFLAGS_EXTRA="$CFLAGS_EXTRA" "$test_target" V=1
 	cp run.out run.out."${arch}"
 	"${MAKE[@]}" report | grep passed