Re: [v6 PATCH 01/21] x86/mpx: Use signed variables to compute effective addresses

From: Borislav Petkov
Date: Tue Apr 11 2017 - 17:56:31 EST


On Tue, Mar 07, 2017 at 04:32:34PM -0800, Ricardo Neri wrote:
> Even though memory addresses are unsigned. The operands used to compute the

... unsigned, the operands ...

> effective address do have a sign. This is true for the r/m part of the
> ModRM byte, the base and index parts of the SiB byte as well as the
> displacement. Thus, signed variables shall be used when computing the
> effective address from these operands. Once the signed effective address
> has been computed, it is casted to an unsigned long to determine the
> linear address.
>
> Variables are renamed to better reflect the type of address being
> computed.

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
--