1c2a08812e
If CONFIG_IOMMU_DEBUG_TRACKING=y, a deadlock will occur if userspace
writes to the debugfs file "attach":
-001|context_switch(inline)
-001|__schedule()
-002|__preempt_count_sub(inline)
-002|schedule()
-003|schedule_timeout()
-004|do_wait_for_common(inline)
-004|__wait_for_common(inline)
-004|wait_for_common()
-005|wait_for_completion()
-006|__synchronize_srcu()
-007|synchronize_srcu()
-008|debugfs_remove_recursive()
-009|iommu_debug_detach_device()
-010|__iommu_detach_device()
-011|__iommu_group_for_each_dev(inline)
-011|__iommu_detach_group()
-012|iommu_detach_device()
-013|iommu_debug_device_profiling()
-014|iommu_debug_device_show()
-015|seq_read()
-016|full_proxy_read()
-017|__vfs_read()
-018|vfs_read()
Since the files in the attachment directory are rarely used, remove
them. Update the data saved by this config option to work properly
with iommu groups.
Change-Id: I3f0f1d0836f37412915ce3e78d8aefe92dc8d096
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
[lmark@codeaurora.org: deadlock is not an issue on this branch
but this change is backported because there are security benefits
from removing the iommu debugfs attachments nodes, such as removing
register access.]
Signed-off-by: Liam Mark <lmark@codeaurora.org>
34 lines
1 KiB
C
34 lines
1 KiB
C
/* Copyright (c) 2015-2017, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef IOMMU_DEBUG_H
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#define IOMMU_DEBUG_H
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#ifdef CONFIG_IOMMU_DEBUG_TRACKING
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void iommu_debug_attach_device(struct iommu_domain *domain, struct device *dev);
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void iommu_debug_domain_remove(struct iommu_domain *domain);
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#else /* !CONFIG_IOMMU_DEBUG_TRACKING */
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static inline void iommu_debug_attach_device(struct iommu_domain *domain,
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struct device *dev)
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{
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}
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static inline void iommu_debug_domain_remove(struct iommu_domain *domain)
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{
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}
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#endif /* CONFIG_IOMMU_DEBUG_TRACKING */
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#endif /* IOMMU_DEBUG_H */
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