Re: [PATCH 29/29] x86/fpu: Defer FPU state load until return to userspace

[Sebastian Andrzej Siewior]

On 2018-11-28 23:20:35 [+0100], To linux-kernel@xxxxxxxxxxxxxxx wrote:
> --- a/arch/x86/kernel/fpu/signal.c
> +++ b/arch/x86/kernel/fpu/signal.c
> @@ -228,13 +228,12 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
>  	struct task_struct *tsk = current;
>  	struct fpu *fpu = &tsk->thread.fpu;
>  	int state_size = fpu_kernel_xstate_size;
> -	union fpregs_state *state;
> -	void *tmp;
>  	struct user_i387_ia32_struct env;
>  	struct user_i387_ia32_struct *envp = NULL;
>  	int ret = 0;
>  	u64 xfeatures = 0;
>  	int fx_only = 0;
> +	int err;
>  
â
>  	} else if (use_fxsr()) {
> -		ret = __copy_from_user(&state->fxsave, buf_fx, state_size);
> -		if (ret)
> +		ret = __copy_from_user(&fpu->state.fxsave, buf_fx, state_size);
> +		if (ret) {
> +			err = -EFAULT;
>  			goto err_out;
> +		}

After reworking the series after addressing the comments for 08/29 I
noticed that `err' should have been `ret'. 

Sebastian