[PATCH v6 01/10] powerpc/uaccess: Add unsafe_copy_from_user

[Christophe Leroy]

Le 21/02/2021 à 02:23, Christopher M. Riedl a écrit :
> Just wrap __copy_tofrom_user() for the usual 'unsafe' pattern which
> accepts a label to goto on error.
> 
> Signed-off-by: Christopher M. Riedl <cmr at codefail.de>
> Reviewed-by: Daniel Axtens <dja at axtens.net>
> ---
>   arch/powerpc/include/asm/uaccess.h | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
> index 78e2a3990eab..33b2de642120 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -487,6 +487,9 @@ user_write_access_begin(const void __user *ptr, size_t len)
>   #define unsafe_put_user(x, p, e) \
>   	__unsafe_put_user_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
>   
> +#define unsafe_copy_from_user(d, s, l, e) \
> +	unsafe_op_wrap(__copy_tofrom_user((__force void __user *)d, s, l), e)
> +

Could we perform same as unsafe_copy_to_user() instead of calling an external function which is 
banned in principle inside uaccess blocks ?


>   #define unsafe_copy_to_user(d, s, l, e) \
>   do {									\
>   	u8 __user *_dst = (u8 __user *)(d);				\
>