[x86-64 psABI] RFC: Extend x86-64 PLT entry to support MPX

[Florian Weimer]

On 07/23/2013 09:49 PM, H.J. Lu wrote:
>   2. Extend the current 16-byte PLT entry:
>
>    ff 25 32 8b 21 00        jmpq   *name@GOTPCREL(%rip)
>    68 00 00 00 00           pushq  $index
>    e9 00 00 00 00           jmpq   PLT0
>
>      which clear bound registers, to 32-byte to add BND prefix to branch
>      instructions.

Would it be possible to use a different instruction sequence that stays 
in the 16 byte limit?  Or restrict MPX support to BIND_NOW relocations?

-- 
Florian Weimer / Red Hat Product Security Team