Re: [PATCH v1 09/10] gdb/linux-tdep: parse ProtectionKey in /proc/PID/smaps

[Matthieu Longo <matthieu.longo@arm.com>]

On 14/07/2026 10:12, Matthieu Longo wrote:
> On 09/07/2026 07:42, Thiago Jung Bauermann wrote:
>>
>> There's nothing in this patch series that uses the parsed pkey, so IMHO
>> (other maintainers may disagree) it makes more sense if this patch is
>> committed together with a patch that makes use of the field.
>>
> 
> Nothing uses it yet because it is still unclear how to expose it to the users.
> I assume that "info proc mappings" is a good place to do it.
> 
> As a reminder those are the existing columns:
> Start Addr         End Addr           Size               Offset             Perms File
> 
> Should we add a new column "Protection Key" or "PKey" between "Offset" and "Perms" ?
> What do you think ?
> 

Additionally, if we were to print the permissions associated with a PKey, what do you think about
the following view ?

Start Addr         End Addr           Size               Offset    PKey     Perms File
0x0000000000400000 0x0000000000483000 0x83000            0x0       0        r-xp  /path/to/file
    ...
0x00000000004a2000 0x00000000004a7000 0x5000             0x0       1        rw-p
    Thread 1: effective: r--  overlay: r--
    Thread 3: effective: rw-  overlay: rw-
    Thread 4: effective: r--  overlay: r-x

Effective being the effective permissions resulting from the ANDing of the base permissions (coming
from "Perms") AND the overlay permissions attached to a thread (permissions associated to the PKey.
The look-up of those overlay permissions is platform-specific).

If no protection key support exists on the target, the PKey column would not be printed.
Same for the threads' permissions (effective and overlay).

Does this approach look fine to you ? Does it overload the view ?
Should the dumping of effective and overlay permissions be part of a generic or platform-specific
command ?

Matthieu