Re: [PATCH 2/4] sparc: fix accurate exception reporting in copy_{from_to}_user for UltraSPARC III

[Rene Rebe <rene@exactcode.com>]

Hi,

From: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>

> Based on a finding by Anthony Yznaga that the UltraSPARC III copy_from_user
> returns invalid values breaking other parts of the kernel in case of a
> fault, while the generic implementation is correct.

Tested-by: René Rebe <rene@exactcode.com> # UltraSparc III+ and UltraSparc IIIi

> Fixes: ee841d0aff64 ("sparc64: Convert U3copy_{from,to}_user to accurate exception reporting.")
> Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
> ---
>  arch/sparc/lib/U3memcpy.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/sparc/lib/U3memcpy.S b/arch/sparc/lib/U3memcpy.S
> index 9248d59c734c..bace3a18f836 100644
> --- a/arch/sparc/lib/U3memcpy.S
> +++ b/arch/sparc/lib/U3memcpy.S
> @@ -267,6 +267,7 @@ FUNC_NAME:	/* %o0=dst, %o1=src, %o2=len */
>  	faligndata	%f10, %f12, %f26
>  	EX_LD_FP(LOAD(ldd, %o1 + 0x040, %f0), U3_retl_o2)
>  
> +	and		%o2, 0x3f, %o2
>  	subcc		GLOBAL_SPARE, 0x80, GLOBAL_SPARE
>  	add		%o1, 0x40, %o1
>  	bgu,pt		%XCC, 1f
> @@ -336,7 +337,6 @@ FUNC_NAME:	/* %o0=dst, %o1=src, %o2=len */
>  	 * Also notice how this code is careful not to perform a
>  	 * load past the end of the src buffer.
>  	 */
> -	and		%o2, 0x3f, %o2
>  	andcc		%o2, 0x38, %g2
>  	be,pn		%XCC, 2f
>  	 subcc		%g2, 0x8, %g2
> -- 
> 2.50.1
> 
> 

-- 
  René Rebe, ExactCODE GmbH, Berlin, Germany
  https://exactcode.com | https://t2linux.com | https://rene.rebe.de