arch: copy_thread: pass clone_flags as u64

[ Upstream commit bbc46b23af ]

With the introduction of clone3 in commit 7f192e3cd3 ("fork: add
clone3") the effective bit width of clone_flags on all architectures was
increased from 32-bit to 64-bit, with a new type of u64 for the flags.
However, for most consumers of clone_flags the interface was not
changed from the previous type of unsigned long.

While this works fine as long as none of the new 64-bit flag bits
(CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still
undesirable in terms of the principle of least surprise.

Thus, this commit fixes all relevant interfaces of the copy_thread
function that is called from copy_process to consistently pass
clone_flags as u64, so that no truncation to 32-bit integers occurs on
32-bit architectures.

Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com>
Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-3-53fcf5577d57@siemens-energy.com
Fixes: c5febea095 ("fork: Pass struct kernel_clone_args into copy_thread")
Acked-by: Guo Ren (Alibaba Damo Academy) <guoren@kernel.org>
Acked-by: Andreas Larsson <andreas@gaisler.com> # sparc
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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);

arch/nios2/kernel/process.c

@@ -101,7 +101,7 @@ 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/openrisc/kernel/process.c

@@ -165,7 +165,7 @@ extern 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 *userregs;

arch/parisc/kernel/process.c

@@ -201,7 +201,7 @@ arch_initcall(parisc_idle_init);
 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 *cregs = &(p->thread.regs);

arch/powerpc/kernel/process.c

@@ -1805,7 +1805,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 			f = ret_from_kernel_user_thread;
 		} else {
 			struct pt_regs *regs = current_pt_regs();
-			unsigned long clone_flags = args->flags;
+			u64 clone_flags = args->flags;
 			unsigned long usp = args->stack;
 
 			/* Copy registers */

arch/riscv/kernel/process.c

@@ -223,7 +223,7 @@ asmlinkage void ret_from_fork_user(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 pt_regs *childregs = task_pt_regs(p);

arch/s390/kernel/process.c

@@ -106,7 +106,7 @@ 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 new_stackp = args->stack;
 	unsigned long tls = args->tls;
 	struct fake_frame

arch/sh/kernel/process_32.c

@@ -89,7 +89,7 @@ asmlinkage void ret_from_kernel_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 thread_info *ti = task_thread_info(p);

arch/sparc/kernel/process_32.c

@@ -260,7 +260,7 @@ extern void ret_from_kernel_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 sp = args->stack;
 	unsigned long tls = args->tls;
 	struct thread_info *ti = task_thread_info(p);

arch/sparc/kernel/process_64.c

@@ -567,7 +567,7 @@ barf:
  */
 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 sp = args->stack;
 	unsigned long tls = args->tls;
 	struct thread_info *t = task_thread_info(p);

arch/um/kernel/process.c

@@ -143,7 +143,7 @@ static void fork_handler(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 sp = args->stack;
 	unsigned long tls = args->tls;
 	void (*handler)(void);

arch/x86/include/asm/fpu/sched.h

@@ -11,7 +11,7 @@
 
 extern void save_fpregs_to_fpstate(struct fpu *fpu);
 extern void fpu__drop(struct task_struct *tsk);
-extern int  fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
+extern int  fpu_clone(struct task_struct *dst, u64 clone_flags, bool minimal,
 		      unsigned long shstk_addr);
 extern void fpu_flush_thread(void);
 

arch/x86/include/asm/shstk.h

@@ -16,7 +16,7 @@ struct thread_shstk {
 
 long shstk_prctl(struct task_struct *task, int option, unsigned long arg2);
 void reset_thread_features(void);
-unsigned long shstk_alloc_thread_stack(struct task_struct *p, unsigned long clone_flags,
+unsigned long shstk_alloc_thread_stack(struct task_struct *p, u64 clone_flags,
 				       unsigned long stack_size);
 void shstk_free(struct task_struct *p);
 int setup_signal_shadow_stack(struct ksignal *ksig);
@@ -28,7 +28,7 @@ static inline long shstk_prctl(struct task_struct *task, int option,
 			       unsigned long arg2) { return -EINVAL; }
 static inline void reset_thread_features(void) {}
 static inline unsigned long shstk_alloc_thread_stack(struct task_struct *p,
-						     unsigned long clone_flags,
+						     u64 clone_flags,
 						     unsigned long stack_size) { return 0; }
 static inline void shstk_free(struct task_struct *p) {}
 static inline int setup_signal_shadow_stack(struct ksignal *ksig) { return 0; }

arch/x86/kernel/fpu/core.c

@@ -631,7 +631,7 @@ static int update_fpu_shstk(struct task_struct *dst, unsigned long ssp)
 }
 
 /* Clone current's FPU state on fork */
-int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
+int fpu_clone(struct task_struct *dst, u64 clone_flags, bool minimal,
 	      unsigned long ssp)
 {
 	/*

arch/x86/kernel/process.c

@@ -159,7 +159,7 @@ __visible void ret_from_fork(struct task_struct *prev, 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 sp = args->stack;
 	unsigned long tls = args->tls;
 	struct inactive_task_frame *frame;

arch/x86/kernel/shstk.c

@@ -191,7 +191,7 @@ void reset_thread_features(void)
 	current->thread.features_locked = 0;
 }
 
-unsigned long shstk_alloc_thread_stack(struct task_struct *tsk, unsigned long clone_flags,
+unsigned long shstk_alloc_thread_stack(struct task_struct *tsk, u64 clone_flags,
 				       unsigned long stack_size)
 {
 	struct thread_shstk *shstk = &tsk->thread.shstk;

arch/xtensa/kernel/process.c

@@ -267,7 +267,7 @@ 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_thread_fn = args->stack;
 	unsigned long tls = args->tls;
 	struct pt_regs *childregs = task_pt_regs(p);