Merge patch series "nios2: Add architecture support for clone3"

Simon Schuster <schuster.simon@siemens-energy.com> says:

This series adds support for the clone3 system call to the nios2
architecture. This addresses the build-time warning "warning: clone3()
entry point is missing, please fix" introduced in 505d66d
("clone3: drop __ARCH_WANT_SYS_CLONE3 macro"). The implementation passes
the relevant clone3 tests of kselftest when applied on top of
next-20250815:

	./run_kselftest.sh
	TAP version 13
	1..4
	# selftests: clone3: clone3
	ok 1 selftests: clone3: clone3
	# selftests: clone3: clone3_clear_sighand
	ok 2 selftests: clone3: clone3_clear_sighand
	# selftests: clone3: clone3_set_tid
	ok 3 selftests: clone3: clone3_set_tid
	# selftests: clone3: clone3_cap_checkpoint_restore
	ok 4 selftests: clone3: clone3_cap_checkpoint_restore

The series also includes a small patch to kernel/fork.c that ensures
that clone_flags are passed correctly on architectures where unsigned
long is insufficient to store the u64 clone_flags. It is marked as a fix
for stable backporting.

As requested, in v2, this series now further tries to correct this type
error throughout the whole code base. Thus, it now touches a larger
number of subsystems and all architectures.

Therefore, another test was performed for ARCH=x86_64 (as a
representative for 64-bit architectures). Here, the series builds cleanly
without warnings on defconfig with CONFIG_SECURITY_APPARMOR=y and
CONFIG_SECURITY_TOMOYO=y (to compile-check the LSM-related changes).
The build further successfully passes testing/selftests/clone3 (with the
patch from 20241105062948.1037011-1-zhouyuhang1010@163.com to prepare
clone3_cap_checkpoint_restore for compatibility with the newer libcap
version on my system).

* patches from https://lore.kernel.org/20250901-nios2-implement-clone3-v2-0-53fcf5577d57@siemens-energy.com:
  nios2: implement architecture-specific portion of sys_clone3
  arch: copy_thread: pass clone_flags as u64
  copy_process: pass clone_flags as u64 across calltree
  copy_sighand: Handle architectures where sizeof(unsigned long) < sizeof(u64)

Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-0-53fcf5577d57@siemens-energy.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

arch/alpha/kernel/process.c

@@ -231,7 +231,7 @@ flush_thread(void)
  */
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	extern void ret_from_fork(void);

arch/arc/kernel/process.c

@@ -166,7 +166,7 @@ asmlinkage void ret_from_fork(void);
  */
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	struct pt_regs *c_regs;        /* child's pt_regs */

arch/arm/kernel/process.c

@@ -234,7 +234,7 @@ asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long stack_start = args->stack;
 	unsigned long tls = args->tls;
 	struct thread_info *thread = task_thread_info(p);

arch/arm64/kernel/process.c

@@ -409,7 +409,7 @@ asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long stack_start = args->stack;
 	unsigned long tls = args->tls;
 	struct pt_regs *childregs = task_pt_regs(p);

arch/csky/kernel/process.c

@@ -32,7 +32,7 @@ void flush_thread(void){}
 
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	struct switch_stack *childstack;

arch/hexagon/kernel/process.c

@@ -52,7 +52,7 @@ void arch_cpu_idle(void)
  */
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	struct thread_info *ti = task_thread_info(p);

arch/loongarch/kernel/process.c

@@ -167,7 +167,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 	unsigned long childksp;
 	unsigned long tls = args->tls;
 	unsigned long usp = args->stack;
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	struct pt_regs *childregs, *regs = current_pt_regs();
 
 	childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE;

arch/m68k/kernel/process.c

@@ -141,7 +141,7 @@ asmlinkage int m68k_clone3(struct pt_regs *regs)
 
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	struct fork_frame {

arch/microblaze/kernel/process.c

@@ -54,7 +54,7 @@ void flush_thread(void)
 
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	struct pt_regs *childregs = task_pt_regs(p);

arch/mips/kernel/process.c

@@ -107,7 +107,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
  */
 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
-	unsigned long clone_flags = args->flags;
+	u64 clone_flags = args->flags;
 	unsigned long usp = args->stack;
 	unsigned long tls = args->tls;
 	struct thread_info *ti = task_thread_info(p);