Re: [PATCH] x86/ptrace: Use savesegment() in get_segment_reg() instead of inline asm

[Oleg Nesterov <oleg@redhat.com>]

On 04/02, Uros Bizjak wrote:
>
> @@ -251,32 +251,31 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
>  	/*
>  	 * Returning the value truncates it to 16 bits.
>  	 */
> -	unsigned int seg;
> +	unsigned int retval;

LGTM, but perhaps it would be better to use "u16 retval" ? and remove the
comment.

Oleg.

>  
>  	switch (offset) {
>  	case offsetof(struct user_regs_struct, fs):
>  		if (task == current) {
> -			/* Older gas can't assemble movq %?s,%r?? */
> -			asm("movl %%fs,%0" : "=r" (seg));
> -			return seg;
> +			savesegment(fs, retval);
> +			return retval;
>  		}
>  		return task->thread.fsindex;
>  	case offsetof(struct user_regs_struct, gs):
>  		if (task == current) {
> -			asm("movl %%gs,%0" : "=r" (seg));
> -			return seg;
> +			savesegment(gs, retval);
> +			return retval;
>  		}
>  		return task->thread.gsindex;
>  	case offsetof(struct user_regs_struct, ds):
>  		if (task == current) {
> -			asm("movl %%ds,%0" : "=r" (seg));
> -			return seg;
> +			savesegment(ds, retval);
> +			return retval;
>  		}
>  		return task->thread.ds;
>  	case offsetof(struct user_regs_struct, es):
>  		if (task == current) {
> -			asm("movl %%es,%0" : "=r" (seg));
> -			return seg;
> +			savesegment(es, retval);
> +			return retval;
>  		}
>  		return task->thread.es;
>  
> -- 
> 2.53.0
>