perf_allow_cpu() and perf_allow_tracepoint() are static inline and
reach into a non-exported sysctl, so modular drivers that want the
same permission model as system-wide perf end up writing partial
copies of this code. Let's instead export these properly so that modules
can call them.

Commit 5e9629d0ae97 ("drivers/perf: arm_spe: Use perf_allow_kernel()
for permissions") already moved perf_allow_kernel() out of line and
exported it. Patch 1 does the same for the other two, and provides
!CONFIG_PERF_EVENTS stubs so the helpers stay callable when perf is
compiled out.

Patch 2 converts drm/xe's OA and EU stall paths to call
perf_allow_cpu(), so xe observation now respects the system
perf_event_paranoid policy and consults the LSM hook. Sites that have
already configured an LSM perf policy or tuned the paranoid sysctl will
now see those settings honored on xe as well.

Changes since v1:

* Patch 1: add !CONFIG_PERF_EVENTS stubs that fall back to
  perfmon_capable() so the helpers remain callable when perf is
  compiled out. The sashiko-bot AI review caught that the v1 code
  would otherwise fail to build with PERF_EVENTS=n.

John Hubbard (2):
  perf/core: out-of-line and export perf_allow_cpu/tracepoint()
  drm/xe: gate observation streams with perf_allow_cpu()

 drivers/gpu/drm/xe/xe_eu_stall.c    |  5 +++--
 drivers/gpu/drm/xe/xe_oa.c          | 25 +++++++++++++---------
 drivers/gpu/drm/xe/xe_observation.c | 32 ++++++++++++++++++++++++-----
 drivers/gpu/drm/xe/xe_observation.h |  3 +--
 include/linux/perf_event.h          | 31 ++++++++++++++--------------
 kernel/events/core.c                | 18 ++++++++++++++++
 6 files changed, 79 insertions(+), 35 deletions(-)


base-commit: 79bd2dded182b1d458b18e62684b7f82ffc682e5
-- 
2.54.0

On Fri, May 22, 2026 at 06:33:24PM -0700, John Hubbard wrote:
> perf_allow_cpu() and perf_allow_tracepoint() are static inline and
> reach into a non-exported sysctl, so modular drivers that want the
> same permission model as system-wide perf end up writing partial
> copies of this code. Let's instead export these properly so that modules
> can call them.
> 
> Commit 5e9629d0ae97 ("drivers/perf: arm_spe: Use perf_allow_kernel()
> for permissions") already moved perf_allow_kernel() out of line and
> exported it. Patch 1 does the same for the other two, and provides
> !CONFIG_PERF_EVENTS stubs so the helpers stay callable when perf is
> compiled out.
> 
> Patch 2 converts drm/xe's OA and EU stall paths to call
> perf_allow_cpu(), so xe observation now respects the system
> perf_event_paranoid policy and consults the LSM hook. Sites that have
> already configured an LSM perf policy or tuned the paranoid sysctl will
> now see those settings honored on xe as well.
> 
> Changes since v1:
> 
> * Patch 1: add !CONFIG_PERF_EVENTS stubs that fall back to
>   perfmon_capable() so the helpers remain callable when perf is
>   compiled out. The sashiko-bot AI review caught that the v1 code
>   would otherwise fail to build with PERF_EVENTS=n.
> 
> John Hubbard (2):
>   perf/core: out-of-line and export perf_allow_cpu/tracepoint()
>   drm/xe: gate observation streams with perf_allow_cpu()
> 
>  drivers/gpu/drm/xe/xe_eu_stall.c    |  5 +++--
>  drivers/gpu/drm/xe/xe_oa.c          | 25 +++++++++++++---------
>  drivers/gpu/drm/xe/xe_observation.c | 32 ++++++++++++++++++++++++-----
>  drivers/gpu/drm/xe/xe_observation.h |  3 +--
>  include/linux/perf_event.h          | 31 ++++++++++++++--------------
>  kernel/events/core.c                | 18 ++++++++++++++++
>  6 files changed, 79 insertions(+), 35 deletions(-)

Sure, works for me. How do you want to route these things, Xe tree or
-tip?

On 5/23/26 1:40 AM, Peter Zijlstra wrote:
> On Fri, May 22, 2026 at 06:33:24PM -0700, John Hubbard wrote:
...
>>    perf/core: out-of-line and export perf_allow_cpu/tracepoint()
>>    drm/xe: gate observation streams with perf_allow_cpu()
>>
>>   drivers/gpu/drm/xe/xe_eu_stall.c    |  5 +++--
>>   drivers/gpu/drm/xe/xe_oa.c          | 25 +++++++++++++---------
>>   drivers/gpu/drm/xe/xe_observation.c | 32 ++++++++++++++++++++++++-----
>>   drivers/gpu/drm/xe/xe_observation.h |  3 +--
>>   include/linux/perf_event.h          | 31 ++++++++++++++--------------
>>   kernel/events/core.c                | 18 ++++++++++++++++
>>   6 files changed, 79 insertions(+), 35 deletions(-)
> 
> Sure, works for me. How do you want to route these things, Xe tree or
> -tip?

Hi Peter,

Maybe -tip, but really, either way is perfectly OK with me.

thanks,
-- 
John Hubbard