Re: PowerPC exec page protection

[Anton Blanchard <anton@au1.ibm.com>]

Hi,

> <asm-ppc/pgtable.h> and <asm-ppc64/pgtable.h> both define the
> following map of protection bits:
> 
>     #define __P000  PAGE_NONE
>     #define __P001  PAGE_READONLY_X
>     #define __P010  PAGE_COPY
>     #define __P011  PAGE_COPY_X
>     #define __P100  PAGE_READONLY
>     #define __P101  PAGE_READONLY_X
>     #define __P110  PAGE_COPY
>     #define __P111  PAGE_COPY_X
> 
>     #define __S000  PAGE_NONE
>     #define __S001  PAGE_READONLY_X
>     #define __S010  PAGE_SHARED
>     #define __S011  PAGE_SHARED_X
>     #define __S100  PAGE_READONLY
>     #define __S101  PAGE_READONLY_X
>     #define __S110  PAGE_SHARED
>     #define __S111  PAGE_SHARED_X
> 
> The _X flags seem wrongly placed, as bit 2 is the PROT_EXEC bit, not
> bit 0.  Is the above intentional?

Its backwards and we know it :) Ive got a patch to implement per page
execute on ppc64 and that did pop up.

Thanks for pointing it out, are you looking at ppc* page protection or
just chanced upon it?

Anton