[PATCH v6 3/6] syscall.h: introduce syscall_set_nr()

[Maciej W. Rozycki]

On Mon, 17 Feb 2025, Dmitry V. Levin wrote:

> diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
> index ea050b23d428..b956b015641c 100644
> --- a/arch/mips/include/asm/syscall.h
> +++ b/arch/mips/include/asm/syscall.h
> @@ -41,6 +41,20 @@ static inline long syscall_get_nr(struct task_struct *task,
>  	return task_thread_info(task)->syscall;
>  }
>  
> +static inline void syscall_set_nr(struct task_struct *task,
> +				  struct pt_regs *regs,
> +				  int nr)
> +{
> +	/*
> +	 * New syscall number has to be assigned to regs[2] because
> +	 * syscall_trace_entry() loads it from there unconditionally.

 That label is called `trace_a_syscall' in arch/mips/kernel/scall64-o32.S 
instead.  To bring some order and avoid an inaccuracy here should the odd 
one be matched to the other three?

> +	 *
> +	 * Consequently, if the syscall was indirect and nr != __NR_syscall,
> +	 * then after this assignment the syscall will cease to be indirect.
> +	 */
> +	task_thread_info(task)->syscall = regs->regs[2] = nr;
> +}
> +
>  static inline void mips_syscall_update_nr(struct task_struct *task,
>  					  struct pt_regs *regs)
>  {

 Otherwise:

Reviewed-by: Maciej W. Rozycki <macro at orcam.me.uk>

for this part, thank you!

  Maciej