Re: [RFC][PATCH 01/22] x86 user stack frame reads: switch to explicit __get_user()

[Peter Zijlstra]

On Mon, Mar 23, 2020 at 06:37:58PM +0000, Al Viro wrote:
> From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> 
> rather than relying upon the magic in raw_copy_from_user()
> 
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>


> diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
> index 61d93f062a36..ab8eab43a8a2 100644
> --- a/arch/x86/include/asm/uaccess.h
> +++ b/arch/x86/include/asm/uaccess.h
> @@ -695,15 +695,6 @@ extern struct movsl_mask {
>  #endif
>  
>  /*
> - * We rely on the nested NMI work to allow atomic faults from the NMI path; the
> - * nested NMI paths are careful to preserve CR2.
> - *
> - * Caller must use pagefault_enable/disable, or run in interrupt context,
> - * and also do a uaccess_ok() check
> - */
> -#define __copy_from_user_nmi __copy_from_user_inatomic
> -
> -/*
>   * The "unsafe" user accesses aren't really "unsafe", but the naming
>   * is a big fat warning: you have to not only do the access_ok()
>   * checking before using them, but you have to surround them with the

Thanks for killing that remnant!

Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>