syscall.h: add syscall_set_arguments()

This function is going to be needed on all HAVE_ARCH_TRACEHOOK
architectures to implement PTRACE_SET_SYSCALL_INFO API.

This partially reverts commit 7962c2eddbfe ("arch: remove unused function
syscall_set_arguments()") by reusing some of old syscall_set_arguments()
implementations.

[[e-mail]: fix compile time fortify checks]
Link: https://lkml.kernel.org/r/20250408213131.GA2872426@ax162
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Dmitry V. Levin <[e-mail]>
Signed-off-by: Nathan Chancellor <[e-mail]>
Tested-by: Charlie Jenkins <[e-mail]>
Reviewed-by: Charlie Jenkins <[e-mail]>
Acked-by: Helge Deller <[e-mail]> # parisc
Reviewed-by: Maciej W. Rozycki <[e-mail]> [mips]
Cc: Alexander Gordeev <[e-mail]>
Cc: Alexey Gladkov (Intel) <[e-mail]>
Cc: Andreas Larsson <[e-mail]>
Cc: anton ivanov <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Borislav Betkov <[e-mail]>
Cc: Brian Cain <[e-mail]>
Cc: Christian Borntraeger <[e-mail]>
Cc: Christian Zankel <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Davide Berardi <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Dinh Nguyen <[e-mail]>
Cc: Eugene Syromiatnikov <[e-mail]>
Cc: Eugene Syromyatnikov <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Guo Ren <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Johannes Berg <[e-mail]>
Cc: John Paul Adrian Glaubitz <[e-mail]>
Cc: Jonas Bonn <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Max Filippov <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Michal Simek <[e-mail]>
Cc: Mike Frysinger <[e-mail]>
Cc: Naveen N Rao <[e-mail]>
Cc: Nicholas Piggin <[e-mail]>
Cc: Oleg Nesterov <[e-mail]>
Cc: Renzo Davoi <[e-mail]>
Cc: Richard Weinberger <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Russel King <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Stafford Horne <[e-mail]>
Cc: Stefan Kristiansson <[e-mail]>
Cc: Sven Schnelle <[e-mail]>
Cc: Thomas Gleinxer <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: WANG Xuerui <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

arch/arc/include/asm/syscall.h

···
 	}
 }
 
+static inline void
+syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+		      unsigned long *args)
+{
+	unsigned long *inside_ptregs = &regs->r0;
+	unsigned int n = 6;
+	unsigned int i = 0;
+
+	while (n--) {
+		*inside_ptregs = args[i++];
+		inside_ptregs--;
+	}
+}
+
 static inline int
 syscall_get_arch(struct task_struct *task)
 {

arch/arm/include/asm/syscall.h

···
 	memcpy(args, &regs->ARM_r0 + 1, 5 * sizeof(args[0]));
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	memcpy(&regs->ARM_r0, args, 6 * sizeof(args[0]));
+	/*
+	 * Also copy the first argument into ARM_ORIG_r0
+	 * so that syscall_get_arguments() would return it
+	 * instead of the previous value.
+	 */
+	regs->ARM_ORIG_r0 = regs->ARM_r0;
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	/* ARM tasks don't change audit architectures on the fly. */

arch/arm64/include/asm/syscall.h

···
 	memcpy(args, &regs->regs[1], 5 * sizeof(args[0]));
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	memcpy(&regs->regs[0], args, 6 * sizeof(args[0]));
+	/*
+	 * Also copy the first argument into orig_x0
+	 * so that syscall_get_arguments() would return it
+	 * instead of the previous value.
+	 */
+	regs->orig_x0 = regs->regs[0];
+}
+
 /*
  * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
  * AArch64 has the same system calls both on little- and big- endian.

arch/csky/include/asm/syscall.h

···
 	memcpy(args, &regs->a1, 5 * sizeof(args[0]));
 }
 
+static inline void
+syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+		      const unsigned long *args)
+{
+	memcpy(&regs->a0, args, 6 * sizeof(regs->a0));
+	/*
+	 * Also copy the first argument into orig_a0
+	 * so that syscall_get_arguments() would return it
+	 * instead of the previous value.
+	 */
+	regs->orig_a0 = regs->a0;
+}
+
 static inline int
 syscall_get_arch(struct task_struct *task)
 {

arch/hexagon/include/asm/syscall.h

···
 	memcpy(args, &(&regs->r00)[0], 6 * sizeof(args[0]));
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned long *args)
+{
+	memcpy(&(&regs->r00)[0], args, 6 * sizeof(args[0]));
+}
+
 static inline long syscall_get_error(struct task_struct *task,
 				     struct pt_regs *regs)
 {

arch/loongarch/include/asm/syscall.h

···
 	memcpy(&args[1], &regs->regs[5], 5 * sizeof(long));
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned long *args)
+{
+	regs->orig_a0 = args[0];
+	memcpy(&regs->regs[5], &args[1], 5 * sizeof(long));
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_LOONGARCH64;

arch/mips/include/asm/syscall.h

···
 #endif
 }
 
+static inline void mips_set_syscall_arg(unsigned long *arg,
+	struct task_struct *task, struct pt_regs *regs, unsigned int n)
+{
+#ifdef CONFIG_32BIT
+	switch (n) {
+	case 0: case 1: case 2: case 3:
+		regs->regs[4 + n] = *arg;
+		return;
+	case 4: case 5: case 6: case 7:
+		*arg = regs->args[n] = *arg;
+		return;
+	}
+#else
+	regs->regs[4 + n] = *arg;
+#endif
+}
+
 static inline long syscall_get_error(struct task_struct *task,
 				     struct pt_regs *regs)
 {
···
 
 	while (n--)
 		mips_get_syscall_arg(args++, task, regs, i++);
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned long *args)
+{
+	unsigned int i = 0;
+	unsigned int n = 6;
+
+	while (n--)
+		mips_set_syscall_arg(args++, task, regs, i++);
 }
 
 extern const unsigned long sys_call_table[];

arch/nios2/include/asm/syscall.h

···
 	*args   = regs->r9;
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+	struct pt_regs *regs, const unsigned long *args)
+{
+	regs->r4 = *args++;
+	regs->r5 = *args++;
+	regs->r6 = *args++;
+	regs->r7 = *args++;
+	regs->r8 = *args++;
+	regs->r9 = *args;
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_NIOS2;

arch/openrisc/include/asm/syscall.h

···
 	memcpy(args, &regs->gpr[3], 6 * sizeof(args[0]));
 }
 
+static inline void
+syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+		      const unsigned long *args)
+{
+	memcpy(&regs->gpr[3], args, 6 * sizeof(args[0]));
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_OPENRISC;

arch/parisc/include/asm/syscall.h

···
 	args[0] = regs->gr[26];
 }
 
+static inline void syscall_set_arguments(struct task_struct *tsk,
+					 struct pt_regs *regs,
+					 unsigned long *args)
+{
+	regs->gr[21] = args[5];
+	regs->gr[22] = args[4];
+	regs->gr[23] = args[3];
+	regs->gr[24] = args[2];
+	regs->gr[25] = args[1];
+	regs->gr[26] = args[0];
+}
+
 static inline long syscall_get_error(struct task_struct *task,
 				     struct pt_regs *regs)
 {

arch/powerpc/include/asm/syscall.h

···
 	}
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	memcpy(&regs->gpr[3], args, 6 * sizeof(args[0]));
+
+	/* Also copy the first argument into orig_gpr3 */
+	regs->orig_gpr3 = args[0];
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	if (is_tsk_32bit_task(task))

arch/riscv/include/asm/syscall.h

···
 	args[5] = regs->a5;
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	regs->orig_a0 = args[0];
+	regs->a1 = args[1];
+	regs->a2 = args[2];
+	regs->a3 = args[3];
+	regs->a4 = args[4];
+	regs->a5 = args[5];
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 #ifdef CONFIG_64BIT

arch/s390/include/asm/syscall.h

···
 	args[0] = regs->orig_gpr2 & mask;
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	regs->orig_gpr2 = args[0];
+	for (int n = 1; n < 6; n++)
+		regs->gprs[2 + n] = args[n];
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 #ifdef CONFIG_COMPAT

arch/sh/include/asm/syscall_32.h

···
 	args[0] = regs->regs[4];
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	regs->regs[1] = args[5];
+	regs->regs[0] = args[4];
+	regs->regs[7] = args[3];
+	regs->regs[6] = args[2];
+	regs->regs[5] = args[1];
+	regs->regs[4] = args[0];
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	int arch = AUDIT_ARCH_SH;

arch/sparc/include/asm/syscall.h

···
 	}
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	unsigned int i;
+
+	for (i = 0; i < 6; i++)
+		regs->u_regs[UREG_I0 + i] = args[i];
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 #if defined(CONFIG_SPARC64) && defined(CONFIG_COMPAT)

arch/um/include/asm/syscall-generic.h

···
 	*args   = UPT_SYSCALL_ARG6(r);
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	struct uml_pt_regs *r = &regs->regs;
+
+	UPT_SYSCALL_ARG1(r) = *args++;
+	UPT_SYSCALL_ARG2(r) = *args++;
+	UPT_SYSCALL_ARG3(r) = *args++;
+	UPT_SYSCALL_ARG4(r) = *args++;
+	UPT_SYSCALL_ARG5(r) = *args++;
+	UPT_SYSCALL_ARG6(r) = *args;
+}
+
 /* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */
 
 #endif	/* __UM_SYSCALL_GENERIC_H */

arch/x86/include/asm/syscall.h

···
 	args[5] = regs->bp;
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	regs->bx = args[0];
+	regs->cx = args[1];
+	regs->dx = args[2];
+	regs->si = args[3];
+	regs->di = args[4];
+	regs->bp = args[5];
+}
+
 static inline int syscall_get_arch(struct task_struct *task)
 {
 	return AUDIT_ARCH_I386;
···
 		*args++ = regs->r10;
 		*args++ = regs->r8;
 		*args   = regs->r9;
+	}
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+# ifdef CONFIG_IA32_EMULATION
+	if (task->thread_info.status & TS_COMPAT) {
+		regs->bx = *args++;
+		regs->cx = *args++;
+		regs->dx = *args++;
+		regs->si = *args++;
+		regs->di = *args++;
+		regs->bp = *args;
+	} else
+# endif
+	{
+		regs->di = *args++;
+		regs->si = *args++;
+		regs->dx = *args++;
+		regs->r10 = *args++;
+		regs->r8 = *args++;
+		regs->r9 = *args;
 	}
 }
 

arch/xtensa/include/asm/syscall.h

···
 		args[i] = regs->areg[reg[i]];
 }
 
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 const unsigned long *args)
+{
+	static const unsigned int reg[] = XTENSA_SYSCALL_ARGUMENT_REGS;
+	unsigned int i;
+
+	for (i = 0; i < 6; ++i)
+		regs->areg[reg[i]] = args[i];
+}
+
 asmlinkage long xtensa_rt_sigreturn(void);
 asmlinkage long xtensa_shmat(int, char __user *, int);
 asmlinkage long xtensa_fadvise64_64(int, int,

include/asm-generic/syscall.h

···
 			   unsigned long *args);
 
 /**
+ * syscall_set_arguments - change system call parameter value
+ * @task:	task of interest, must be in system call entry tracing
+ * @regs:	task_pt_regs() of @task
+ * @args:	array of argument values to store
+ *
+ * Changes 6 arguments to the system call.
+ * The first argument gets value @args[0], and so on.
+ *
+ * It's only valid to call this when @task is stopped for tracing on
+ * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
+ */
+void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+			   const unsigned long *args);
+
+/**
  * syscall_get_arch - return the AUDIT_ARCH for the current system call
  * @task:	task of interest, must be blocked
  *