ARM: 6975/1: pmu: reject duplicate PMU registrations

Currently, the PMU reservation framework allows for multiple PMUs of
the same type to register themselves. This can lead to a bug with the
sequence:

register_pmu(pmu1);
reserve_pmu(pmu_type);
register_pmu(pmu2);
release_pmu(pmu1);

Here, pmu1 cannot be released, and pmu2 cannot be reserved.

This patch modifies register_pmu to reject registrations where a PMU is
already present, preventing this problem. PMUs which can have multiple
instances should not use the PMU reservation framework.

Signed-off-by: Mark Rutland <[email protected]>
Acked-by: Jamie Iles <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Russell King <[email protected]>

0 files changed, 0 insertions, 0 deletions