Re: [RFC] User stack pointer randomisation

[Ralf Baechle <ralf@linux-mips.org>]

On Thu, Jul 19, 2007 at 01:47:19PM +0200, Franck Bui-Huu wrote:

> this is weird I would have defined them like this instead:
> 
> #if (_MIPS_SIM == _MIPS_SIM_ABI32)
> #define ALSZ 8
> #elif (_MIPS_SIM == _MIPS_SIM_NABI32) || (_MIPS_SIM == _MIPS_SIM_ABI64)
> #define ALSZ 16
> #endif
> 
> #define ALMASK (~(ALSZ-1))

<asm/asm.h> which is fairly similar to it's userspace equivalent <sys/asm.h>
contains definitions which are some sort of pseudo-standard in the MIPS
world, including ALSZ and ALMASK.  If I had choosen them I'd have set
ALSZ to 8 rsp. 16, just like you ...  Anyway, having similar macros makes
porting of assembler code easier.  This also is why <asm/regdef.h> and
<asm/fpregdef.h> are as they are.  RISC/os, IRIX, some of the BSD variants,
even the non-Linux SDE variants for example for baremetal use a similar
set of macros and headers.

  Ralf