| Message ID | 1307546911-2714-3-git-send-email-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jun 08, 2011 at 04:28:31PM +0100, Mark Rutland wrote: > 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 <mark.rutland@arm.com> > Acked-By Will Deacon <will.deacon@arm.com> > Cc: Jamie Iles <jamie@jamieiles.com> Acked-by: Jamie Iles <jamie@jamieiles.com> Jamie
diff --git a/arch/arm/kernel/pmu.c b/arch/arm/kernel/pmu.c index 87942b9..de6b1b0 100644 --- a/arch/arm/kernel/pmu.c +++ b/arch/arm/kernel/pmu.c @@ -34,13 +34,13 @@ static int __devinit pmu_register(struct platform_device *pdev, return -EINVAL; } - if (pmu_devices[type]) - pr_warning("registering new PMU device type %d overwrites " - "previous registration!\n", type); - else - pr_info("registered new PMU device of type %d\n", - type); + if (pmu_devices[type]) { + pr_warning("rejecting duplicate registration of PMU device " + "type %d.", type); + return -ENOSPC; + } + pr_info("registered new PMU device of type %d\n", type); pmu_devices[type] = pdev; return 0; }
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 <mark.rutland@arm.com> Acked-By Will Deacon <will.deacon@arm.com> Cc: Jamie Iles <jamie@jamieiles.com> --- arch/arm/kernel/pmu.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-)