diff --git a/Documentation/dev-tools/kunit/style.rst b/Documentation/dev-tools/kunit/style.rst
index b6d0d7359f00..eac81a714a29 100644
--- a/Documentation/dev-tools/kunit/style.rst
+++ b/Documentation/dev-tools/kunit/style.rst
@@ -188,15 +188,26 @@ For example, a Kconfig entry might look like:
 Test File and Module Names
 ==========================
 
-KUnit tests can often be compiled as a module. These modules should be named
-after the test suite, followed by ``_test``. If this is likely to conflict with
-non-KUnit tests, the suffix ``_kunit`` can also be used.
+KUnit tests are often compiled as a separate module. To avoid conflicting
+with regular modules, KUnit modules should be named after the test suite,
+followed by ``_kunit`` (e.g. if "foobar" is the core module, then
+"foobar_kunit" is the KUnit test module).
 
-The easiest way of achieving this is to name the file containing the test suite
-``<suite>_test.c`` (or, as above, ``<suite>_kunit.c``). This file should be
-placed next to the code under test.
+Test source files, whether compiled as a separate module or an
+``#include`` in another source file, are best kept in a ``tests/``
+subdirectory to not conflict with other source files (e.g. for
+tab-completion).
+
+Note that the ``_test`` suffix has also been used in some existing
+tests. The ``_kunit`` suffix is preferred, as it makes the distinction
+between KUnit and non-KUnit tests clearer.
+
+So for the common case, name the file containing the test suite
+``tests/<suite>_kunit.c``. The ``tests`` directory should be placed at
+the same level as the code under test. For example, tests for
+``lib/string.c`` live in ``lib/tests/string_kunit.c``.
 
 If the suite name contains some or all of the name of the test's parent
-directory, it may make sense to modify the source filename to reduce redundancy.
-For example, a ``foo_firmware`` suite could be in the ``foo/firmware_test.c``
-file.
+directory, it may make sense to modify the source filename to reduce
+redundancy. For example, a ``foo_firmware`` suite could be in the
+``foo/tests/firmware_kunit.c`` file.
diff --git a/include/kunit/visibility.h b/include/kunit/visibility.h
index 0dfe35feeec6..efff77b58dd6 100644
--- a/include/kunit/visibility.h
+++ b/include/kunit/visibility.h
@@ -22,6 +22,7 @@
      * EXPORTED_FOR_KUNIT_TESTING namespace only if CONFIG_KUNIT is
      * enabled. Must use MODULE_IMPORT_NS(EXPORTED_FOR_KUNIT_TESTING)
      * in test file in order to use symbols.
+     * @symbol: the symbol identifier to export
      */
     #define EXPORT_SYMBOL_IF_KUNIT(symbol) EXPORT_SYMBOL_NS(symbol, \
 	    EXPORTED_FOR_KUNIT_TESTING)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 26354671b37d..074ca51b7ea5 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3059,3 +3059,19 @@ config RUST_KERNEL_DOCTESTS
 endmenu # "Rust"
 
 endmenu # Kernel hacking
+
+config INT_POW_TEST
+	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This option enables the KUnit test suite for the int_pow function,
+	  which performs integer exponentiation. The test suite is designed to
+	  verify that the implementation of int_pow correctly computes the power
+	  of a given base raised to a given exponent.
+
+	  Enabling this option will include tests that check various scenarios
+	  and edge cases to ensure the accuracy and reliability of the exponentiation
+	  function.
+
+	  If unsure, say N
diff --git a/lib/math/Makefile b/lib/math/Makefile
index 91fcdb0c9efe..3c1f92a7459d 100644
--- a/lib/math/Makefile
+++ b/lib/math/Makefile
@@ -5,5 +5,6 @@ obj-$(CONFIG_CORDIC)		+= cordic.o
 obj-$(CONFIG_PRIME_NUMBERS)	+= prime_numbers.o
 obj-$(CONFIG_RATIONAL)		+= rational.o
 
+obj-$(CONFIG_INT_POW_TEST)  += tests/int_pow_kunit.o
 obj-$(CONFIG_TEST_DIV64)	+= test_div64.o
 obj-$(CONFIG_RATIONAL_KUNIT_TEST) += rational-test.o
diff --git a/lib/math/tests/Makefile b/lib/math/tests/Makefile
new file mode 100644
index 000000000000..6a169123320a
--- /dev/null
+++ b/lib/math/tests/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_INT_POW_TEST) += int_pow_kunit.o
diff --git a/lib/math/tests/int_pow_kunit.c b/lib/math/tests/int_pow_kunit.c
new file mode 100644
index 000000000000..34b33677d458
--- /dev/null
+++ b/lib/math/tests/int_pow_kunit.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <kunit/test.h>
+#include <linux/math.h>
+
+struct test_case_params {
+	u64 base;
+	unsigned int exponent;
+	u64 expected_result;
+	const char *name;
+};
+
+static const struct test_case_params params[] = {
+	{ 64, 0, 1, "Power of zero" },
+	{ 64, 1, 64, "Power of one"},
+	{ 0, 5, 0, "Base zero" },
+	{ 1, 64, 1, "Base one" },
+	{ 2, 2, 4, "Two squared"},
+	{ 2, 3, 8, "Two cubed"},
+	{ 5, 5, 3125, "Five raised to the fifth power" },
+	{ U64_MAX, 1, U64_MAX, "Max base" },
+	{ 2, 63, 9223372036854775808ULL, "Large result"},
+};
+
+static void get_desc(const struct test_case_params *tc, char *desc)
+{
+	strscpy(desc, tc->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(int_pow, params, get_desc);
+
+static void int_pow_test(struct kunit *test)
+{
+	const struct test_case_params *tc = (const struct test_case_params *)test->param_value;
+
+	KUNIT_EXPECT_EQ(test, tc->expected_result, int_pow(tc->base, tc->exponent));
+}
+
+static struct kunit_case math_int_pow_test_cases[] = {
+	KUNIT_CASE_PARAM(int_pow_test, int_pow_gen_params),
+	{}
+};
+
+static struct kunit_suite int_pow_test_suite = {
+	.name = "math-int_pow",
+	.test_cases = math_int_pow_test_cases,
+};
+
+kunit_test_suites(&int_pow_test_suite);
+
+MODULE_DESCRIPTION("math.int_pow KUnit test suite");
+MODULE_LICENSE("GPL");
diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index e69c26abe1ea..a1f55fb24bb3 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -35,6 +35,7 @@ all_files := \
 		stackprotector.h \
 		std.h \
 		stdarg.h \
+		stdbool.h \
 		stdint.h \
 		stdlib.h \
 		string.h \
diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h
index b23ac1f04035..06fdef7b291a 100644
--- a/tools/include/nolibc/arch-aarch64.h
+++ b/tools/include/nolibc/arch-aarch64.h
@@ -142,13 +142,13 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"mov x0, sp\n"          /* save stack pointer to x0, as arg1 of _start_c */
 		"and sp, x0, -16\n"     /* sp must be 16-byte aligned in the callee      */
 		"bl  _start_c\n"        /* transfer to c runtime                         */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 #endif /* _NOLIBC_ARCH_AARCH64_H */
diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h
index cae4afa7c1c7..6180ff99ab43 100644
--- a/tools/include/nolibc/arch-arm.h
+++ b/tools/include/nolibc/arch-arm.h
@@ -185,15 +185,15 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
-		"mov %r0, sp\n"         /* save stack pointer to %r0, as arg1 of _start_c */
-		"and ip, %r0, #-8\n"    /* sp must be 8-byte aligned in the callee        */
+		"mov r0, sp\n"          /* save stack pointer to %r0, as arg1 of _start_c */
+		"and ip, r0, #-8\n"     /* sp must be 8-byte aligned in the callee        */
 		"mov sp, ip\n"
 		"bl  _start_c\n"        /* transfer to c runtime                          */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_ARM_H */
diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h
index 28c26a00a762..ff5afc35bbd8 100644
--- a/tools/include/nolibc/arch-i386.h
+++ b/tools/include/nolibc/arch-i386.h
@@ -162,7 +162,7 @@
  * 2) The deepest stack frame should be set to zero
  *
  */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"xor  %ebp, %ebp\n"       /* zero the stack frame                                */
@@ -174,7 +174,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"call _start_c\n"         /* transfer to c runtime                               */
 		"hlt\n"                   /* ensure it does not return                           */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_I386_H */
diff --git a/tools/include/nolibc/arch-loongarch.h b/tools/include/nolibc/arch-loongarch.h
index 3f8ef8f86c0f..fb519545959e 100644
--- a/tools/include/nolibc/arch-loongarch.h
+++ b/tools/include/nolibc/arch-loongarch.h
@@ -149,14 +149,14 @@
 #endif
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"move          $a0, $sp\n"         /* save stack pointer to $a0, as arg1 of _start_c */
 		LONG_BSTRINS " $sp, $zero, 3, 0\n" /* $sp must be 16-byte aligned                    */
 		"bl            _start_c\n"         /* transfer to c runtime                          */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_LOONGARCH_H */
diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
index 62cc50ef3288..1791a8ce58da 100644
--- a/tools/include/nolibc/arch-mips.h
+++ b/tools/include/nolibc/arch-mips.h
@@ -179,7 +179,7 @@
 })
 
 /* startup code, note that it's called __start on MIPS */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector __start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector __start(void)
 {
 	__asm__ volatile (
 		".set push\n"
@@ -194,11 +194,13 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"li    $t0, -8\n"
 		"and   $sp, $sp, $t0\n"  /* $sp must be 8-byte aligned                     */
 		"addiu $sp, $sp, -16\n"  /* the callee expects to save a0..a3 there        */
-		"jal   _start_c\n"       /* transfer to c runtime                          */
+		"lui $t9, %hi(_start_c)\n" /* ABI requires current function address in $t9 */
+		"ori $t9, %lo(_start_c)\n"
+		"jalr $t9\n"             /* transfer to c runtime                          */
 		" nop\n"                 /* delayed slot                                   */
 		".set pop\n"
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_MIPS_H */
diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h
index ac212e6185b2..ee2fdb8d601d 100644
--- a/tools/include/nolibc/arch-powerpc.h
+++ b/tools/include/nolibc/arch-powerpc.h
@@ -172,7 +172,7 @@
 	_ret;                                                                \
 })
 
-#ifndef __powerpc64__
+#if !defined(__powerpc64__) && !defined(__clang__)
 /* FIXME: For 32-bit PowerPC, with newer gcc compilers (e.g. gcc 13.1.0),
  * "omit-frame-pointer" fails with __attribute__((no_stack_protector)) but
  * works with __attribute__((__optimize__("-fno-stack-protector")))
@@ -184,7 +184,7 @@
 #endif /* !__powerpc64__ */
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 #ifdef __powerpc64__
 #if _CALL_ELF == 2
@@ -215,7 +215,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"bl     _start_c\n"     /* transfer to c runtime                         */
 	);
 #endif
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_POWERPC_H */
diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h
index 1927c643c739..8827bf936212 100644
--- a/tools/include/nolibc/arch-riscv.h
+++ b/tools/include/nolibc/arch-riscv.h
@@ -140,7 +140,7 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		".option push\n"
@@ -151,7 +151,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"andi sp, a0, -16\n"      /* sp must be 16-byte aligned                    */
 		"call _start_c\n"         /* transfer to c runtime                         */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_RISCV_H */
diff --git a/tools/include/nolibc/arch-s390.h b/tools/include/nolibc/arch-s390.h
index 5d60fd43f883..2ec13d8b9a2d 100644
--- a/tools/include/nolibc/arch-s390.h
+++ b/tools/include/nolibc/arch-s390.h
@@ -139,7 +139,7 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"lgr	%r2, %r15\n"          /* save stack pointer to %r2, as arg1 of _start_c */
@@ -147,7 +147,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"xc	0(8,%r15), 0(%r15)\n" /* clear backchain                                */
 		"brasl	%r14, _start_c\n"     /* transfer to c runtime                          */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 struct s390_mmap_arg_struct {
diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h
index 68609f421934..1e40620a2b33 100644
--- a/tools/include/nolibc/arch-x86_64.h
+++ b/tools/include/nolibc/arch-x86_64.h
@@ -161,7 +161,7 @@
  * 2) The deepest stack frame should be zero (the %rbp).
  *
  */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"xor  %ebp, %ebp\n"       /* zero the stack frame                            */
@@ -170,7 +170,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"call _start_c\n"         /* transfer to c runtime                           */
 		"hlt\n"                   /* ensure it does not return                       */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #define NOLIBC_ARCH_HAS_MEMMOVE
@@ -193,10 +193,10 @@ __asm__ (
 	"movq %rdi, %rdx\n\t"
 	"subq %rsi, %rdx\n\t"
 	"cmpq %rcx, %rdx\n\t"
-	"jb   .Lbackward_copy\n\t"
+	"jb   1f\n\t"
 	"rep movsb\n\t"
 	"retq\n"
-".Lbackward_copy:"
+"1:" /* backward copy */
 	"leaq -1(%rdi, %rcx, 1), %rdi\n\t"
 	"leaq -1(%rsi, %rcx, 1), %rsi\n\t"
 	"std\n\t"
diff --git a/tools/include/nolibc/compiler.h b/tools/include/nolibc/compiler.h
index beddc3665d69..9bc6a706a332 100644
--- a/tools/include/nolibc/compiler.h
+++ b/tools/include/nolibc/compiler.h
@@ -6,20 +6,30 @@
 #ifndef _NOLIBC_COMPILER_H
 #define _NOLIBC_COMPILER_H
 
+#if defined(__has_attribute)
+#  define __nolibc_has_attribute(attr) __has_attribute(attr)
+#else
+#  define __nolibc_has_attribute(attr) 0
+#endif
+
+#if __nolibc_has_attribute(naked)
+#  define __nolibc_entrypoint __attribute__((naked))
+#  define __nolibc_entrypoint_epilogue()
+#else
+#  define __nolibc_entrypoint __attribute__((optimize("Os", "omit-frame-pointer")))
+#  define __nolibc_entrypoint_epilogue() __builtin_unreachable()
+#endif /* __nolibc_has_attribute(naked) */
+
 #if defined(__SSP__) || defined(__SSP_STRONG__) || defined(__SSP_ALL__) || defined(__SSP_EXPLICIT__)
 
 #define _NOLIBC_STACKPROTECTOR
 
 #endif /* defined(__SSP__) ... */
 
-#if defined(__has_attribute)
-#  if __has_attribute(no_stack_protector)
-#    define __no_stack_protector __attribute__((no_stack_protector))
-#  else
-#    define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
-#  endif
+#if __nolibc_has_attribute(no_stack_protector)
+#  define __no_stack_protector __attribute__((no_stack_protector))
 #else
 #  define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
-#endif /* defined(__has_attribute) */
+#endif /* __nolibc_has_attribute(no_stack_protector) */
 
 #endif /* _NOLIBC_COMPILER_H */
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
index 43b551468c2a..bbcd5fd09806 100644
--- a/tools/include/nolibc/crt.h
+++ b/tools/include/nolibc/crt.h
@@ -13,23 +13,24 @@ const unsigned long *_auxv __attribute__((weak));
 static void __stack_chk_init(void);
 static void exit(int);
 
-extern void (*const __preinit_array_start[])(void) __attribute__((weak));
-extern void (*const __preinit_array_end[])(void) __attribute__((weak));
+extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak));
+extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak));
 
-extern void (*const __init_array_start[])(void) __attribute__((weak));
-extern void (*const __init_array_end[])(void) __attribute__((weak));
+extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak));
+extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak));
 
 extern void (*const __fini_array_start[])(void) __attribute__((weak));
 extern void (*const __fini_array_end[])(void) __attribute__((weak));
 
-__attribute__((weak))
+__attribute__((weak,used))
 void _start_c(long *sp)
 {
 	long argc;
 	char **argv;
 	char **envp;
 	int exitcode;
-	void (* const *func)(void);
+	void (* const *ctor_func)(int, char **, char **);
+	void (* const *dtor_func)(void);
 	const unsigned long *auxv;
 	/* silence potential warning: conflicting types for 'main' */
 	int _nolibc_main(int, char **, char **) __asm__ ("main");
@@ -66,16 +67,16 @@ void _start_c(long *sp)
 		;
 	_auxv = auxv;
 
-	for (func = __preinit_array_start; func < __preinit_array_end; func++)
-		(*func)();
-	for (func = __init_array_start; func < __init_array_end; func++)
-		(*func)();
+	for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++)
+		(*ctor_func)(argc, argv, envp);
+	for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++)
+		(*ctor_func)(argc, argv, envp);
 
 	/* go to application */
 	exitcode = _nolibc_main(argc, argv, envp);
 
-	for (func = __fini_array_end; func > __fini_array_start;)
-		(*--func)();
+	for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;)
+		(*--dtor_func)();
 
 	exit(exitcode);
 }
diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
index 989e707263a4..92436b1e4441 100644
--- a/tools/include/nolibc/nolibc.h
+++ b/tools/include/nolibc/nolibc.h
@@ -74,7 +74,8 @@
  *            -I../nolibc -o hello hello.c -lgcc
  *
  * The available standard (but limited) include files are:
- *   ctype.h, errno.h, signal.h, stdarg.h, stdio.h, stdlib.h, string.h, time.h
+ *   ctype.h, errno.h, signal.h, stdarg.h, stdbool.h stdio.h, stdlib.h,
+ *   string.h, time.h
  *
  * In addition, the following ones are expected to be provided by the compiler:
  *   float.h, stddef.h
diff --git a/tools/include/nolibc/stackprotector.h b/tools/include/nolibc/stackprotector.h
index 13f1d0e60387..1d0d5259ec41 100644
--- a/tools/include/nolibc/stackprotector.h
+++ b/tools/include/nolibc/stackprotector.h
@@ -18,7 +18,7 @@
  * triggering stack protector errors themselves
  */
 
-__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
+__attribute__((weak,used,noreturn,section(".text.nolibc_stack_chk")))
 void __stack_chk_fail(void)
 {
 	pid_t pid;
@@ -34,7 +34,7 @@ void __stack_chk_fail_local(void)
 	__stack_chk_fail();
 }
 
-__attribute__((weak,section(".data.nolibc_stack_chk")))
+__attribute__((weak,used,section(".data.nolibc_stack_chk")))
 uintptr_t __stack_chk_guard;
 
 static __no_stack_protector void __stack_chk_init(void)
diff --git a/tools/include/nolibc/stdbool.h b/tools/include/nolibc/stdbool.h
new file mode 100644
index 000000000000..60feece22f17
--- /dev/null
+++ b/tools/include/nolibc/stdbool.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Boolean types support for NOLIBC
+ * Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_STDBOOL_H
+#define _NOLIBC_STDBOOL_H
+
+#define bool _Bool
+#define true 1
+#define false 0
+
+#define __bool_true_false_are_defined 1
+
+#endif /* _NOLIBC_STDBOOL_H */
diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
index f9ab28421e6d..9ec9c24f38c0 100644
--- a/tools/include/nolibc/string.h
+++ b/tools/include/nolibc/string.h
@@ -7,6 +7,7 @@
 #ifndef _NOLIBC_STRING_H
 #define _NOLIBC_STRING_H
 
+#include "arch.h"
 #include "std.h"
 
 static void *malloc(size_t len);
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index 7254c110ff23..61931c4926fd 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -72,7 +72,8 @@ class LinuxSourceTreeOperations:
 			raise ConfigError(e.output.decode())
 
 	def make(self, jobs: int, build_dir: str, make_options: Optional[List[str]]) -> None:
-		command = ['make', 'ARCH=' + self._linux_arch, 'O=' + build_dir, '--jobs=' + str(jobs)]
+		command = ['make', 'all', 'compile_commands.json', 'ARCH=' + self._linux_arch,
+			   'O=' + build_dir, '--jobs=' + str(jobs)]
 		if make_options:
 			command.extend(make_options)
 		if self._cross_compile:
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 3b7df5477317..b38199965f99 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+TARGETS += acct
 TARGETS += alsa
 TARGETS += amd-pstate
 TARGETS += arm64
@@ -109,7 +110,6 @@ TARGETS += tmpfs
 TARGETS += tpm2
 TARGETS += tty
 TARGETS += uevent
-TARGETS += user
 TARGETS += user_events
 TARGETS += vDSO
 TARGETS += mm
diff --git a/tools/testing/selftests/acct/.gitignore b/tools/testing/selftests/acct/.gitignore
new file mode 100644
index 000000000000..7e78aac19038
--- /dev/null
+++ b/tools/testing/selftests/acct/.gitignore
@@ -0,0 +1,3 @@
+acct_syscall
+config
+process_log
\ No newline at end of file
diff --git a/tools/testing/selftests/acct/Makefile b/tools/testing/selftests/acct/Makefile
new file mode 100644
index 000000000000..7e025099cf65
--- /dev/null
+++ b/tools/testing/selftests/acct/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+TEST_GEN_PROGS := acct_syscall
+CFLAGS += -Wall
+
+include ../lib.mk
\ No newline at end of file
diff --git a/tools/testing/selftests/acct/acct_syscall.c b/tools/testing/selftests/acct/acct_syscall.c
new file mode 100644
index 000000000000..e44e8fe1f4a3
--- /dev/null
+++ b/tools/testing/selftests/acct/acct_syscall.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* kselftest for acct() system call
+ *  The acct() system call enables or disables process accounting.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/wait.h>
+
+#include "../kselftest.h"
+
+int main(void)
+{
+	char filename[] = "process_log";
+	FILE *fp;
+	pid_t child_pid;
+	int sz;
+
+	// Setting up kselftest framework
+	ksft_print_header();
+	ksft_set_plan(1);
+
+	// Check if test is run a root
+	if (geteuid()) {
+		ksft_test_result_skip("This test needs root to run!\n");
+		return 1;
+	}
+
+	// Create file to log closed processes
+	fp = fopen(filename, "w");
+
+	if (!fp) {
+		ksft_test_result_error("%s.\n", strerror(errno));
+		ksft_finished();
+		return 1;
+	}
+
+	acct(filename);
+
+	// Handle error conditions
+	if (errno) {
+		ksft_test_result_error("%s.\n", strerror(errno));
+		fclose(fp);
+		ksft_finished();
+		return 1;
+	}
+
+	// Create child process and wait for it to terminate.
+
+	child_pid = fork();
+
+	if (child_pid < 0) {
+		ksft_test_result_error("Creating a child process to log failed\n");
+		acct(NULL);
+		return 1;
+	} else if (child_pid > 0) {
+		wait(NULL);
+		fseek(fp, 0L, SEEK_END);
+		sz = ftell(fp);
+
+		acct(NULL);
+
+		if (sz <= 0) {
+			ksft_test_result_fail("Terminated child process not logged\n");
+			ksft_exit_fail();
+			return 1;
+		}
+
+		ksft_test_result_pass("Successfully logged terminated process.\n");
+		fclose(fp);
+		ksft_exit_pass();
+		return 0;
+	}
+
+	return 1;
+}
diff --git a/tools/testing/selftests/core/Makefile b/tools/testing/selftests/core/Makefile
index ce262d097269..8e99f87f5d7c 100644
--- a/tools/testing/selftests/core/Makefile
+++ b/tools/testing/selftests/core/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 CFLAGS += -g $(KHDR_INCLUDES)
 
-TEST_GEN_PROGS := close_range_test
+TEST_GEN_PROGS := close_range_test unshare_test
 
 include ../lib.mk
 
diff --git a/tools/testing/selftests/core/unshare_test.c b/tools/testing/selftests/core/unshare_test.c
new file mode 100644
index 000000000000..7fec9dfb1b0e
--- /dev/null
+++ b/tools/testing/selftests/core/unshare_test.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/kernel.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <unistd.h>
+#include <sys/resource.h>
+#include <linux/close_range.h>
+
+#include "../kselftest_harness.h"
+#include "../clone3/clone3_selftests.h"
+
+TEST(unshare_EMFILE)
+{
+	pid_t pid;
+	int status;
+	struct __clone_args args = {
+		.flags = CLONE_FILES,
+		.exit_signal = SIGCHLD,
+	};
+	int fd;
+	ssize_t n, n2;
+	static char buf[512], buf2[512];
+	struct rlimit rlimit;
+	int nr_open;
+
+	fd = open("/proc/sys/fs/nr_open", O_RDWR);
+	ASSERT_GE(fd, 0);
+
+	n = read(fd, buf, sizeof(buf));
+	ASSERT_GT(n, 0);
+	ASSERT_EQ(buf[n - 1], '\n');
+
+	ASSERT_EQ(sscanf(buf, "%d", &nr_open), 1);
+
+	ASSERT_EQ(0, getrlimit(RLIMIT_NOFILE, &rlimit));
+
+	/* bump fs.nr_open */
+	n2 = sprintf(buf2, "%d\n", nr_open + 1024);
+	lseek(fd, 0, SEEK_SET);
+	write(fd, buf2, n2);
+
+	/* bump ulimit -n */
+	rlimit.rlim_cur = nr_open + 1024;
+	rlimit.rlim_max = nr_open + 1024;
+	EXPECT_EQ(0, setrlimit(RLIMIT_NOFILE, &rlimit)) {
+		lseek(fd, 0, SEEK_SET);
+		write(fd, buf, n);
+		exit(EXIT_FAILURE);
+	}
+
+	/* get a descriptor past the old fs.nr_open */
+	EXPECT_GE(dup2(2, nr_open + 64), 0) {
+		lseek(fd, 0, SEEK_SET);
+		write(fd, buf, n);
+		exit(EXIT_FAILURE);
+	}
+
+	/* get descriptor table shared */
+	pid = sys_clone3(&args, sizeof(args));
+	EXPECT_GE(pid, 0) {
+		lseek(fd, 0, SEEK_SET);
+		write(fd, buf, n);
+		exit(EXIT_FAILURE);
+	}
+
+	if (pid == 0) {
+		int err;
+
+		/* restore fs.nr_open */
+		lseek(fd, 0, SEEK_SET);
+		write(fd, buf, n);
+		/* ... and now unshare(CLONE_FILES) must fail with EMFILE */
+		err = unshare(CLONE_FILES);
+		EXPECT_EQ(err, -1)
+			exit(EXIT_FAILURE);
+		EXPECT_EQ(errno, EMFILE)
+			exit(EXIT_FAILURE);
+		exit(EXIT_SUCCESS);
+	}
+
+	EXPECT_EQ(waitpid(pid, &status, 0), pid);
+	EXPECT_EQ(true, WIFEXITED(status));
+	EXPECT_EQ(0, WEXITSTATUS(status));
+}
+
+TEST_HARNESS_MAIN
diff --git a/tools/testing/selftests/cpufreq/cpufreq.sh b/tools/testing/selftests/cpufreq/cpufreq.sh
index a8b1dbc0a3a5..e350c521b467 100755
--- a/tools/testing/selftests/cpufreq/cpufreq.sh
+++ b/tools/testing/selftests/cpufreq/cpufreq.sh
@@ -231,6 +231,21 @@ do_suspend()
 
 		for i in `seq 1 $2`; do
 			printf "Starting $1\n"
+
+			if [ "$3" = "rtc" ]; then
+				if ! command -v rtcwake &> /dev/null; then
+					printf "rtcwake could not be found, please install it.\n"
+					return 1
+				fi
+
+				rtcwake -m $filename -s 15
+
+				if [ $? -ne 0 ]; then
+					printf "Failed to suspend using RTC wake alarm\n"
+					return 1
+				fi
+			fi
+
 			echo $filename > $SYSFS/power/state
 			printf "Came out of $1\n"
 
diff --git a/tools/testing/selftests/cpufreq/main.sh b/tools/testing/selftests/cpufreq/main.sh
index a0eb84cf7167..f12ff7416e41 100755
--- a/tools/testing/selftests/cpufreq/main.sh
+++ b/tools/testing/selftests/cpufreq/main.sh
@@ -24,6 +24,8 @@ helpme()
 	[-t <basic: Basic cpufreq testing
 	     suspend: suspend/resume,
 	     hibernate: hibernate/resume,
+	     suspend_rtc: suspend/resume back using the RTC wakeup alarm,
+	     hibernate_rtc: hibernate/resume back using the RTC wakeup alarm,
 	     modtest: test driver or governor modules. Only to be used with -d or -g options,
 	     sptest1: Simple governor switch to produce lockdep.
 	     sptest2: Concurrent governor switch to produce lockdep.
@@ -76,7 +78,8 @@ parse_arguments()
 				helpme
 				;;
 
-			t) # --func_type (Function to perform: basic, suspend, hibernate, modtest, sptest1/2/3/4 (default: basic))
+			t) # --func_type (Function to perform: basic, suspend, hibernate,
+			   # suspend_rtc, hibernate_rtc, modtest, sptest1/2/3/4 (default: basic))
 				FUNC=$OPTARG
 				;;
 
@@ -121,6 +124,14 @@ do_test()
 		do_suspend "hibernate" 1
 		;;
 
+		"suspend_rtc")
+                do_suspend "suspend" 1 rtc
+                ;;
+
+                "hibernate_rtc")
+                do_suspend "hibernate" 1 rtc
+                ;;
+
 		"modtest")
 		# Do we have modules in place?
 		if [ -z $DRIVER_MOD ] && [ -z $GOVERNOR_MOD ]; then
diff --git a/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c b/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
index ea0cdc37b44f..7ee7492138c6 100644
--- a/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
+++ b/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
@@ -257,12 +257,6 @@ TEST_F(attest_fixture, att_inval_addr)
 	att_inval_addr_test(&self->uvio_attest.meas_addr, _metadata, self);
 }
 
-static void __attribute__((constructor)) __constructor_order_last(void)
-{
-	if (!__constructor_order)
-		__constructor_order = _CONSTRUCTOR_ORDER_BACKWARD;
-}
-
 int main(int argc, char **argv)
 {
 	int fd = open(UV_PATH, O_ACCMODE);
diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c
index 6418ded40bdd..071e03532cba 100644
--- a/tools/testing/selftests/exec/execveat.c
+++ b/tools/testing/selftests/exec/execveat.c
@@ -117,7 +117,7 @@ static int check_execveat_invoked_rc(int fd, const char *path, int flags,
 	}
 	if ((WEXITSTATUS(status) != expected_rc) &&
 	    (WEXITSTATUS(status) != expected_rc2)) {
-		ksft_print_msg("child %d exited with %d not %d nor %d\n",
+		ksft_print_msg("child %d exited with %d neither %d nor %d\n",
 			       child, WEXITSTATUS(status), expected_rc,
 			       expected_rc2);
 		ksft_test_result_fail("%s\n", test_name);
diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
index e044f5fc57fd..70cb0c8b21cf 100644
--- a/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
+++ b/tools/testing/selftests/filesystems/statmount/statmount_test_ns.c
@@ -319,8 +319,11 @@ static void test_listmount_ns(void)
 		 * Tell our parent how many mounts we have, and then wait for it
 		 * to tell us we're done.
 		 */
-		write(child_ready_pipe[1], &nr_mounts, sizeof(nr_mounts));
-		read(parent_ready_pipe[0], &cval, sizeof(cval));
+		if (write(child_ready_pipe[1], &nr_mounts, sizeof(nr_mounts)) !=
+					sizeof(nr_mounts))
+			ret = NSID_ERROR;
+		if (read(parent_ready_pipe[0], &cval, sizeof(cval)) != sizeof(cval))
+			ret = NSID_ERROR;
 		exit(NSID_PASS);
 	}
 
diff --git a/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc b/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc
index c45094d1e1d2..094419e190c2 100644
--- a/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc
+++ b/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc
@@ -6,6 +6,18 @@ original_group=`stat -c "%g" .`
 original_owner=`stat -c "%u" .`
 
 mount_point=`stat -c '%m' .`
+
+# If stat -c '%m' does not work (e.g. busybox) or failed, try to use the
+# current working directory (which should be a tracefs) as the mount point.
+if [ ! -d "$mount_point" ]; then
+	if mount | grep -qw $PWD ; then
+		mount_point=$PWD
+	else
+		# If PWD doesn't work, that is an environmental problem.
+		exit_unresolved
+	fi
+fi
+
 mount_options=`mount | grep "$mount_point" | sed -e 's/.*(\(.*\)).*/\1/'`
 
 # find another owner and group that is not the original
@@ -83,32 +95,38 @@ run_tests() {
 	done
 }
 
-mount -o remount,"$new_options" .
+# Run the tests twice as leftovers can cause issues
+for loop in 1 2 ; do
 
-run_tests
+	echo "Running iteration $loop"
 
-mount -o remount,"$mount_options" .
+	mount -o remount,"$new_options" .
 
-for d in "." "events" "events/sched" "events/sched/sched_switch" "events/sched/sched_switch/enable" $canary; do
-	test "$d" $original_group
-done
+	run_tests
+
+	mount -o remount,"$mount_options" .
+
+	for d in "." "events" "events/sched" "events/sched/sched_switch" "events/sched/sched_switch/enable" $canary; do
+		test "$d" $original_group
+	done
 
 # check instances as well
 
-chgrp $other_group instances
+	chgrp $other_group instances
 
-instance="$(mktemp -u test-XXXXXX)"
+	instance="$(mktemp -u test-XXXXXX)"
 
-mkdir instances/$instance
+	mkdir instances/$instance
 
-cd instances/$instance
+	cd instances/$instance
 
-run_tests
+	run_tests
 
-cd ../..
+	cd ../..
 
-rmdir instances/$instance
+	rmdir instances/$instance
 
-chgrp $original_group instances
+	chgrp $original_group instances
+done
 
 exit 0
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc
new file mode 100644
index 000000000000..a275decdc880
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc
@@ -0,0 +1,26 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove/test uprobe events
+# requires: uprobe_events
+
+echo 0 > events/enable
+echo > dynamic_events
+
+echo 'cat /proc/$$/maps' | /bin/sh | \
+	grep "r-xp .*/bin/.*sh$" | \
+	awk '{printf "p:myevent %s:0x%s\n", $6,$3 }' >> uprobe_events
+
+grep -q myevent uprobe_events
+test -d events/uprobes/myevent
+
+echo 1 > events/uprobes/myevent/enable
+echo 'ls' | /bin/sh > /dev/null
+echo 0 > events/uprobes/myevent/enable
+grep -q myevent trace
+
+echo "-:myevent" >> uprobe_events
+! grep -q myevent uprobe_events
+
+echo > uprobe_events
+
+clear_trace
diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc
index 073a748b9380..263f6b798c85 100644
--- a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc
+++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc
@@ -19,7 +19,14 @@ fail() { # mesg
 
 FILTER=set_ftrace_filter
 FUNC1="schedule"
-FUNC2="sched_tick"
+if grep '^sched_tick\b' available_filter_functions; then
+    FUNC2="sched_tick"
+elif grep '^scheduler_tick\b' available_filter_functions; then
+    FUNC2="scheduler_tick"
+else
+    exit_unresolved
+fi
+
 
 ALL_FUNCS="#### all functions enabled ####"
 
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc
index e21c9c27ece4..77f4c07cdcb8 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_char.tc
@@ -1,7 +1,7 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 # description: Kprobe event char type argument
-# requires: kprobe_events
+# requires: kprobe_events available_filter_functions
 
 case `uname -m` in
 x86_64)
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
index 93217d459556..39001073f7ed 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
@@ -1,7 +1,7 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 # description: Kprobe event string type argument
-# requires: kprobe_events
+# requires: kprobe_events available_filter_functions
 
 case `uname -m` in
 x86_64)
diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index 75b7b4ef6cfa..c4bc2aa508c3 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -1357,12 +1357,6 @@ static int libbpf_print_fn(enum libbpf_print_level level,
 	return 0;
 }
 
-static void __attribute__((constructor)) __constructor_order_last(void)
-{
-	if (!__constructor_order)
-		__constructor_order = _CONSTRUCTOR_ORDER_BACKWARD;
-}
-
 int main(int argc, char **argv)
 {
 	/* Use libbpf 1.0 API mode */
diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index b8967b6e29d5..29fedf609611 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -61,6 +61,7 @@
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #endif
 
+#if defined(__i386__) || defined(__x86_64__) /* arch */
 /*
  * gcc cpuid.h provides __cpuid_count() since v4.4.
  * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
@@ -75,6 +76,7 @@
 			      : "=a" (a), "=b" (b), "=c" (c), "=d" (d)	\
 			      : "0" (level), "2" (count))
 #endif
+#endif /* end arch */
 
 /* define kselftest exit codes */
 #define KSFT_PASS  0
@@ -371,15 +373,7 @@ static inline __noreturn __printf(1, 2) void ksft_exit_fail_msg(const char *msg,
 
 static inline __noreturn void ksft_exit_fail_perror(const char *msg)
 {
-#ifndef NOLIBC
 	ksft_exit_fail_msg("%s: %s (%d)\n", msg, strerror(errno), errno);
-#else
-	/*
-	 * nolibc doesn't provide strerror() and it seems
-	 * inappropriate to add one, just print the errno.
-	 */
-	ksft_exit_fail_msg("%s: %d)\n", msg, errno);
-#endif
 }
 
 static inline __noreturn void ksft_exit_xfail(void)
diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 40723a6a083f..a5a72415e37b 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -488,12 +488,6 @@
  * Use once to append a main() to the test file.
  */
 #define TEST_HARNESS_MAIN \
-	static void __attribute__((constructor)) \
-	__constructor_order_last(void) \
-	{ \
-		if (!__constructor_order) \
-			__constructor_order = _CONSTRUCTOR_ORDER_BACKWARD; \
-	} \
 	int main(int argc, char **argv) { \
 		return test_harness_run(argc, argv); \
 	}
@@ -824,7 +818,7 @@
 		item->prev = item; \
 		return;	\
 	} \
-	if (__constructor_order == _CONSTRUCTOR_ORDER_FORWARD) { \
+	if (__constructor_order_forward) { \
 		item->next = NULL; \
 		item->prev = head->prev; \
 		item->prev->next = item; \
@@ -888,10 +882,7 @@ struct __test_xfail {
 	}
 
 static struct __fixture_metadata *__fixture_list = &_fixture_global;
-static int __constructor_order;
-
-#define _CONSTRUCTOR_ORDER_FORWARD   1
-#define _CONSTRUCTOR_ORDER_BACKWARD -1
+static bool __constructor_order_forward;
 
 static inline void __register_fixture(struct __fixture_metadata *f)
 {
@@ -942,7 +933,7 @@ static inline bool __test_passed(struct __test_metadata *metadata)
  * list so tests are run in source declaration order.
  * https://gcc.gnu.org/onlinedocs/gccint/Initialization.html
  * However, it seems not all toolchains do this correctly, so use
- * __constructor_order to detect which direction is called first
+ * __constructor_order_foward to detect which direction is called first
  * and adjust list building logic to get things running in the right
  * direction.
  */
@@ -1337,8 +1328,7 @@ static int test_harness_run(int argc, char **argv)
 
 static void __attribute__((constructor)) __constructor_order_first(void)
 {
-	if (!__constructor_order)
-		__constructor_order = _CONSTRUCTOR_ORDER_FORWARD;
+	__constructor_order_forward = true;
 }
 
 #endif  /* __KSELFTEST_HARNESS_H */
diff --git a/tools/testing/selftests/lib/Makefile b/tools/testing/selftests/lib/Makefile
index ee71fc99d5b5..c52fe3ad8e98 100644
--- a/tools/testing/selftests/lib/Makefile
+++ b/tools/testing/selftests/lib/Makefile
@@ -4,6 +4,5 @@
 # No binaries, but make sure arg-less "make" doesn't trigger "run_tests"
 all:
 
-TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh scanf.sh strscpy.sh
-
+TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh scanf.sh
 include ../lib.mk
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index 645839b50b0a..dc15aba8d0a3 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -2,5 +2,4 @@ CONFIG_TEST_PRINTF=m
 CONFIG_TEST_SCANF=m
 CONFIG_TEST_BITMAP=m
 CONFIG_PRIME_NUMBERS=m
-CONFIG_TEST_STRSCPY=m
 CONFIG_TEST_BITOPS=m
diff --git a/tools/testing/selftests/lib/strscpy.sh b/tools/testing/selftests/lib/strscpy.sh
deleted file mode 100755
index be60ef6e1a7f..000000000000
--- a/tools/testing/selftests/lib/strscpy.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0+
-$(dirname $0)/../kselftest/module.sh "strscpy*" test_strscpy
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 3fbabab46958..8de98ea7af80 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -1,19 +1,21 @@
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for nolibc tests
-include ../../../scripts/Makefile.include
-include ../../../scripts/utilities.mak
-# We need this for the "cc-option" macro.
-include ../../../build/Build.include
+# we're in ".../tools/testing/selftests/nolibc"
+ifeq ($(srctree),)
+srctree := $(patsubst %/tools/testing/selftests/,%,$(dir $(CURDIR)))
+endif
+
+include $(srctree)/tools/scripts/utilities.mak
+# We need this for the "__cc-option" macro.
+include $(srctree)/scripts/Makefile.compiler
 
 ifneq ($(O),)
 ifneq ($(call is-absolute,$(O)),y)
 $(error Only absolute O= parameters are supported)
 endif
-endif
-
-# we're in ".../tools/testing/selftests/nolibc"
-ifeq ($(srctree),)
-srctree := $(patsubst %/tools/testing/selftests/,%,$(dir $(CURDIR)))
+objtree := $(O)
+else
+objtree ?= $(srctree)
 endif
 
 ifeq ($(ARCH),)
@@ -21,7 +23,7 @@ include $(srctree)/scripts/subarch.include
 ARCH = $(SUBARCH)
 endif
 
-objtree ?= $(srctree)
+cc-option = $(call __cc-option, $(CC),$(CLANG_CROSS_FLAGS),$(1),$(2))
 
 # XARCH extends the kernel's ARCH with a few variants of the same
 # architecture that only differ by the configuration, the toolchain
@@ -155,9 +157,22 @@ CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 -W -Wall -Wex
 		$(CFLAGS_$(XARCH)) $(CFLAGS_STACKPROTECTOR) $(CFLAGS_EXTRA)
 LDFLAGS :=
 
+LIBGCC := -lgcc
+
+ifneq ($(LLVM),)
+# Not needed for clang
+LIBGCC :=
+endif
+
+# Modify CFLAGS based on LLVM=
+include $(srctree)/tools/scripts/Makefile.include
+
+# GCC uses "s390", clang "systemz"
+CLANG_CROSS_FLAGS := $(subst --target=s390-linux,--target=systemz-linux,$(CLANG_CROSS_FLAGS))
+
 REPORT  ?= awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{if (!f) printf("\n"); f++; print;} /\[SKIPPED\][\r]*$$/{s++} \
 		END{ printf("\n%3d test(s): %3d passed, %3d skipped, %3d failed => status: ", p+s+f, p, s, f); \
-		if (f) printf("failure\n"); else if (s) printf("warning\n"); else printf("success\n");; \
+		if (f || !p) printf("failure\n"); else if (s) printf("warning\n"); else printf("success\n");; \
 		printf("\nSee all results in %s\n", ARGV[1]); }'
 
 help:
@@ -204,11 +219,11 @@ sysroot/$(ARCH)/include:
 ifneq ($(NOLIBC_SYSROOT),0)
 nolibc-test: nolibc-test.c nolibc-test-linkage.c sysroot/$(ARCH)/include
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
-	  -nostdlib -nostdinc -static -Isysroot/$(ARCH)/include nolibc-test.c nolibc-test-linkage.c -lgcc
+	  -nostdlib -nostdinc -static -Isysroot/$(ARCH)/include nolibc-test.c nolibc-test-linkage.c $(LIBGCC)
 else
 nolibc-test: nolibc-test.c nolibc-test-linkage.c
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
-	  -nostdlib -static -include $(srctree)/tools/include/nolibc/nolibc.h nolibc-test.c nolibc-test-linkage.c -lgcc
+	  -nostdlib -static -include $(srctree)/tools/include/nolibc/nolibc.h nolibc-test.c nolibc-test-linkage.c $(LIBGCC)
 endif
 
 libc-test: nolibc-test.c nolibc-test-linkage.c
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 093d0512f4c5..6fba7025c5e3 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -542,7 +542,7 @@ int expect_strzr(const char *expr, int llen)
 {
 	int ret = 0;
 
-	llen += printf(" = <%s> ", expr);
+	llen += printf(" = <%s> ", expr ? expr : "(null)");
 	if (expr) {
 		ret = 1;
 		result(llen, FAIL);
@@ -561,7 +561,7 @@ int expect_strnz(const char *expr, int llen)
 {
 	int ret = 0;
 
-	llen += printf(" = <%s> ", expr);
+	llen += printf(" = <%s> ", expr ? expr : "(null)");
 	if (!expr) {
 		ret = 1;
 		result(llen, FAIL);
@@ -686,9 +686,10 @@ static void constructor1(void)
 }
 
 __attribute__((constructor))
-static void constructor2(void)
+static void constructor2(int argc, char **argv, char **envp)
 {
-	constructor_test_value *= 2;
+	if (argc && argv && envp)
+		constructor_test_value *= 2;
 }
 
 int run_startup(int min, int max)
diff --git a/tools/testing/selftests/nolibc/run-tests.sh b/tools/testing/selftests/nolibc/run-tests.sh
index 0446e6326a40..e7ecda4ae796 100755
--- a/tools/testing/selftests/nolibc/run-tests.sh
+++ b/tools/testing/selftests/nolibc/run-tests.sh
@@ -15,10 +15,11 @@ download_location="${cache_dir}/crosstools/"
 build_location="$(realpath "${cache_dir}"/nolibc-tests/)"
 perform_download=0
 test_mode=system
-CFLAGS_EXTRA="-Werror"
+werror=1
+llvm=
 archs="i386 x86_64 arm64 arm mips32le mips32be ppc ppc64 ppc64le riscv s390 loongarch"
 
-TEMP=$(getopt -o 'j:d:c:b:a:m:peh' -n "$0" -- "$@")
+TEMP=$(getopt -o 'j:d:c:b:a:m:pelh' -n "$0" -- "$@")
 
 eval set -- "$TEMP"
 unset TEMP
@@ -42,6 +43,7 @@ Options:
  -b [DIR]       Build location (default: ${build_location})
  -m [MODE]      Test mode user/system (default: ${test_mode})
  -e             Disable -Werror
+ -l             Build with LLVM/clang
 EOF
 }
 
@@ -69,7 +71,10 @@ while true; do
 			test_mode="$2"
 			shift 2; continue ;;
 		'-e')
-			CFLAGS_EXTRA=""
+			werror=0
+			shift; continue ;;
+		'-l')
+			llvm=1
 			shift; continue ;;
 		'-h')
 			print_usage
@@ -140,7 +145,10 @@ test_arch() {
 	ct_abi=$(crosstool_abi "$1")
 	cross_compile=$(realpath "${download_location}gcc-${crosstool_version}-nolibc/${ct_arch}-${ct_abi}/bin/${ct_arch}-${ct_abi}-")
 	build_dir="${build_location}/${arch}"
-	MAKE=(make -j"${nproc}" XARCH="${arch}" CROSS_COMPILE="${cross_compile}" O="${build_dir}")
+	if [ "$werror" -ne 0 ]; then
+		CFLAGS_EXTRA="$CFLAGS_EXTRA -Werror"
+	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
diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index 742782438ca3..94cfdba5308d 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -290,12 +290,12 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param
 
 static bool arch_supports_noncont_cat(const struct resctrl_test *test)
 {
-	unsigned int eax, ebx, ecx, edx;
-
 	/* AMD always supports non-contiguous CBM. */
 	if (get_vendor() == ARCH_AMD)
 		return true;
 
+#if defined(__i386__) || defined(__x86_64__) /* arch */
+	unsigned int eax, ebx, ecx, edx;
 	/* Intel support for non-contiguous CBM needs to be discovered. */
 	if (!strcmp(test->resource, "L3"))
 		__cpuid_count(0x10, 1, eax, ebx, ecx, edx);
@@ -305,6 +305,9 @@ static bool arch_supports_noncont_cat(const struct resctrl_test *test)
 		return false;
 
 	return ((ecx >> 3) & 1);
+#endif /* end arch */
+
+	return false;
 }
 
 static int noncont_cat_run_test(const struct resctrl_test *test,
diff --git a/tools/testing/selftests/rtc/rtctest.c b/tools/testing/selftests/rtc/rtctest.c
index 5df7316ca61a..185580ab9358 100644
--- a/tools/testing/selftests/rtc/rtctest.c
+++ b/tools/testing/selftests/rtc/rtctest.c
@@ -412,13 +412,6 @@ TEST_F_TIMEOUT(rtc, alarm_wkalm_set_minute, 65) {
 }
 #endif
 
-static void __attribute__((constructor))
-__constructor_order_last(void)
-{
-	if (!__constructor_order)
-		__constructor_order = _CONSTRUCTOR_ORDER_BACKWARD;
-}
-
 int main(int argc, char **argv)
 {
 	switch (argc) {
diff --git a/tools/testing/selftests/rust/config b/tools/testing/selftests/rust/config
index b4002acd40bc..5f942b5c8c17 100644
--- a/tools/testing/selftests/rust/config
+++ b/tools/testing/selftests/rust/config
@@ -1,5 +1,6 @@
+# CONFIG_GCC_PLUGINS is not set
 CONFIG_RUST=y
 CONFIG_SAMPLES=y
 CONFIG_SAMPLES_RUST=y
 CONFIG_SAMPLE_RUST_MINIMAL=m
-CONFIG_SAMPLE_RUST_PRINT=m
\ No newline at end of file
+CONFIG_SAMPLE_RUST_PRINT=m
diff --git a/tools/testing/selftests/timers/change_skew.c b/tools/testing/selftests/timers/change_skew.c
index 4421cd562c24..18e794a46c23 100644
--- a/tools/testing/selftests/timers/change_skew.c
+++ b/tools/testing/selftests/timers/change_skew.c
@@ -30,9 +30,6 @@
 #include <time.h>
 #include "../kselftest.h"
 
-#define NSEC_PER_SEC 1000000000LL
-
-
 int change_skew_test(int ppm)
 {
 	struct timex tx;
diff --git a/tools/testing/selftests/timers/skew_consistency.c b/tools/testing/selftests/timers/skew_consistency.c
index c8e6bffe4e0a..83450145fe65 100644
--- a/tools/testing/selftests/timers/skew_consistency.c
+++ b/tools/testing/selftests/timers/skew_consistency.c
@@ -36,8 +36,6 @@
 #include <sys/wait.h>
 #include "../kselftest.h"
 
-#define NSEC_PER_SEC 1000000000LL
-
 int main(int argc, char **argv)
 {
 	struct timex tx;
diff --git a/tools/testing/selftests/timers/threadtest.c b/tools/testing/selftests/timers/threadtest.c
index 76b38e41d9c7..d5564bbf0e50 100644
--- a/tools/testing/selftests/timers/threadtest.c
+++ b/tools/testing/selftests/timers/threadtest.c
@@ -38,10 +38,10 @@ struct timespec global_list[LISTSIZE];
 int listcount = 0;
 
 
-void checklist(struct timespec *list, int size)
+void checklist(const struct timespec *list, int size)
 {
 	int i, j;
-	struct timespec *a, *b;
+	const struct timespec *a, *b;
 
 	/* scan the list */
 	for (i = 0; i < size-1; i++) {
diff --git a/tools/testing/selftests/tpm2/test_async.sh b/tools/testing/selftests/tpm2/test_async.sh
index 43bf5bd772fd..cf5a9c826097 100755
--- a/tools/testing/selftests/tpm2/test_async.sh
+++ b/tools/testing/selftests/tpm2/test_async.sh
@@ -7,4 +7,4 @@ ksft_skip=4
 [ -e /dev/tpm0 ] || exit $ksft_skip
 [ -e /dev/tpmrm0 ] || exit $ksft_skip
 
-python3 -m unittest -v tpm2_tests.AsyncTest
+python3 -m unittest -v tpm2_tests.AsyncTest 2>&1
diff --git a/tools/testing/selftests/tpm2/test_smoke.sh b/tools/testing/selftests/tpm2/test_smoke.sh
index 58af963e5b55..20fa70f970a9 100755
--- a/tools/testing/selftests/tpm2/test_smoke.sh
+++ b/tools/testing/selftests/tpm2/test_smoke.sh
@@ -6,4 +6,4 @@ ksft_skip=4
 
 [ -e /dev/tpm0 ] || exit $ksft_skip
 
-python3 -m unittest -v tpm2_tests.SmokeTest
+python3 -m unittest -v tpm2_tests.SmokeTest 2>&1
diff --git a/tools/testing/selftests/tpm2/test_space.sh b/tools/testing/selftests/tpm2/test_space.sh
index 04c47b13fe8a..93894cbc89a8 100755
--- a/tools/testing/selftests/tpm2/test_space.sh
+++ b/tools/testing/selftests/tpm2/test_space.sh
@@ -6,4 +6,4 @@ ksft_skip=4
 
 [ -e /dev/tpmrm0 ] || exit $ksft_skip
 
-python3 -m unittest -v tpm2_tests.SpaceTest
+python3 -m unittest -v tpm2_tests.SpaceTest 2>&1
diff --git a/tools/testing/selftests/user/Makefile b/tools/testing/selftests/user/Makefile
deleted file mode 100644
index 640a40f9b72b..000000000000
--- a/tools/testing/selftests/user/Makefile
+++ /dev/null
@@ -1,9 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-# Makefile for user memory selftests
-
-# No binaries, but make sure arg-less "make" doesn't trigger "run_tests"
-all:
-
-TEST_PROGS := test_user_copy.sh
-
-include ../lib.mk
diff --git a/tools/testing/selftests/user/config b/tools/testing/selftests/user/config
deleted file mode 100644
index 784ed8416324..000000000000
--- a/tools/testing/selftests/user/config
+++ /dev/null
@@ -1 +0,0 @@
-CONFIG_TEST_USER_COPY=m
diff --git a/tools/testing/selftests/user/test_user_copy.sh b/tools/testing/selftests/user/test_user_copy.sh
deleted file mode 100755
index f9b31a57439b..000000000000
--- a/tools/testing/selftests/user/test_user_copy.sh
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-# Runs copy_to/from_user infrastructure using test_user_copy kernel module
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-if ! /sbin/modprobe -q -n test_user_copy; then
-	echo "user: module test_user_copy is not found [SKIP]"
-	exit $ksft_skip
-fi
-if /sbin/modprobe -q test_user_copy; then
-	/sbin/modprobe -q -r test_user_copy
-	echo "user_copy: ok"
-else
-	echo "user_copy: [FAIL]"
-	exit 1
-fi