From ae0c3751ab08d3fe039d48935e9ad2c46711b23b Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Wed, 22 Jun 2011 15:32:48 +0100
Subject: [PATCH] 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 <mark.rutland@arm.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/kernel/pmu.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/arm/kernel/pmu.c b/arch/arm/kernel/pmu.c
index 87942b931c62..de6b1b0860c2 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;
}
--
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