linux/kernel/irq, branch v3.19

genirq: Prevent proc race against freeing of irq descriptors

2014-12-13T12:33:07Z

Since the rework of the sparse interrupt code to actually free the unused interrupt descriptors there exists a race between the /proc interfaces to the irq subsystem and the code which frees the interrupt descriptor. CPU0 CPU1 show_interrupts() desc = irq_to_desc(X); free_desc(desc) remove_from_radix_tree(); kfree(desc); raw_spinlock_irq(&desc->lock); /proc/interrupts is the only interface which can actively corrupt kernel memory via the lock access. /proc/stat can only read from freed memory. Extremly hard to trigger, but possible. The interfaces in /proc/irq/N/ are not affected by this because the removal of the proc file is serialized in procfs against concurrent readers/writers. The removal happens before the descriptor is freed. For architectures which have CONFIG_SPARSE_IRQ=n this is a non issue as the descriptor is never freed. It's merely cleared out with the irq descriptor lock held. So any concurrent proc access will either see the old correct value or the cleared out ones. Protect the lookup and access to the irq descriptor in show_interrupts() with the sparse_irq_lock. Provide kstat_irqs_usr() which is protecting the lookup and access with sparse_irq_lock and switch /proc/stat to use it. Document the existing kstat_irqs interfaces so it's clear that the caller needs to take care about protection. The users of these interfaces are either not affected due to SPARSE_IRQ=n or already protected against removal. Fixes: 1f5a5b87f78f "genirq: Implement a sane sparse_irq allocator" Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org

Merge branch 'irq-irqdomain-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-12-10T17:01:01Z

Pull irq domain updates from Thomas Gleixner: "The real interesting irq updates: - Support for hierarchical irq domains: For complex interrupt routing scenarios where more than one interrupt related chip is involved we had no proper representation in the generic interrupt infrastructure so far. That made people implement rather ugly constructs in their nested irq chip implementations. The main offenders are x86 and arm/gic. To distangle that mess we have now hierarchical irqdomains which seperate the various interrupt chips and connect them via the hierarchical domains. That keeps the domain specific details internal to the particular hierarchy level and removes the criss/cross referencing of chip internals. The resulting hierarchy for a complex x86 system will look like this: vector mapped: 74 msi-0 mapped: 2 dmar-ir-1 mapped: 69 ioapic-1 mapped: 4 ioapic-0 mapped: 20 pci-msi-2 mapped: 45 dmar-ir-0 mapped: 3 ioapic-2 mapped: 1 pci-msi-1 mapped: 2 htirq mapped: 0 Neither ioapic nor pci-msi know about the dmar interrupt remapping between themself and the vector domain. If interrupt remapping is disabled ioapic and pci-msi become direct childs of the vector domain. In hindsight we should have done that years ago, but in hindsight we always know better :) - Support for generic MSI interrupt domain handling We have more and more non PCI related MSI interrupts, so providing a generic infrastructure for this is better than having all affected architectures implementing their own private hacks. - Support for PCI-MSI interrupt domain handling, based on the generic MSI support. This part carries the pci/msi branch from Bjorn Helgaas pci tree to avoid a massive conflict. The PCI/MSI parts are acked by Bjorn. I have two more branches on top of this. The full conversion of x86 to hierarchical domains and a partial conversion of arm/gic" * 'irq-irqdomain-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) genirq: Move irq_chip_write_msi_msg() helper to core PCI/MSI: Allow an msi_controller to be associated to an irq domain PCI/MSI: Provide mechanism to alloc/free MSI/MSIX interrupt from irqdomain PCI/MSI: Enhance core to support hierarchy irqdomain PCI/MSI: Move cached entry functions to irq core genirq: Provide default callbacks for msi_domain_ops genirq: Introduce msi_domain_alloc/free_irqs() asm-generic: Add msi.h genirq: Add generic msi irq domain support genirq: Introduce callback irq_chip.irq_write_msi_msg genirq: Work around __irq_set_handler vs stacked domains ordering issues irqdomain: Introduce helper function irq_domain_add_hierarchy() irqdomain: Implement a method to automatically call parent domains alloc/free genirq: Introduce helper irq_domain_set_info() to reduce duplicated code genirq: Split out flow handler typedefs into seperate header file genirq: Add IRQ_SET_MASK_OK_DONE to support stacked irqchip genirq: Introduce irq_chip.irq_compose_msi_msg() to support stacked irqchip genirq: Add more helper functions to support stacked irq_chip genirq: Introduce helper functions to support stacked irq_chip irqdomain: Do irq_find_mapping and set_type for hierarchy irqdomain in case OF ...

genirq: Move irq_chip_write_msi_msg() helper to core

2014-12-07T20:49:45Z

No point to expose this to the world. The only legitimate user is the core code. Signed-off-by: Thomas Gleixner Cc: Jiang Liu Cc: Marc Zyngier

PCI/MSI: Move cached entry functions to irq core

2014-11-23T12:01:47Z

Required to support non PCI based MSI. [ tglx: Extracted from Jiangs patch series ] Signed-off-by: Jiang Liu Signed-off-by: Thomas Gleixner

genirq: Provide default callbacks for msi_domain_ops

2014-11-23T12:01:47Z

Extend struct msi_domain_info and provide default callbacks for msi_domain_ops. Signed-off-by: Jiang Liu Cc: Tony Luck Cc: linux-arm-kernel@lists.infradead.org Cc: Bjorn Helgaas Cc: Grant Likely Cc: Marc Zyngier Cc: Yijing Wang Cc: Yingjoe Chen Cc: Borislav Petkov Cc: Matthias Brugger Cc: Alexander Gordeev Link: http://lkml.kernel.org/r/1416061447-9472-8-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner

genirq: Introduce msi_domain_alloc/free_irqs()

2014-11-23T12:01:47Z

Introduce msi_domain_{alloc|free}_irqs() to alloc/free interrupts from generic MSI irqdomain. Signed-off-by: Jiang Liu Cc: Tony Luck Cc: linux-arm-kernel@lists.infradead.org Cc: Bjorn Helgaas Cc: Grant Likely Cc: Marc Zyngier Cc: Yijing Wang Cc: Yingjoe Chen Cc: Borislav Petkov Cc: Matthias Brugger Cc: Alexander Gordeev Link: http://lkml.kernel.org/r/1416061447-9472-7-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner

genirq: Add generic msi irq domain support

2014-11-23T12:01:47Z

Implement the basic functions for MSI interrupt support with hierarchical interrupt domains. [ tglx: Extracted and combined from several patches ] Signed-off-by: Jiang Liu Cc: Bjorn Helgaas Cc: Grant Likely Cc: Marc Zyngier Cc: Yingjoe Chen Cc: Yijing Wang Signed-off-by: Thomas Gleixner

genirq: Work around __irq_set_handler vs stacked domains ordering issues

2014-11-23T12:01:47Z

With the introduction of stacked domains, we have the issue that, depending on where in the stack this is called, __irq_set_handler will succeed or fail: If this is called from the inner irqchip, __irq_set_handler() will fail, as it will look at the outer domain as the (desc->irq_data.chip == &no_irq_chip) test fails (we haven't set the top level yet). This patch implements the following: "If there is at least one valid irqchip in the domain, it will probably sort itself out". This is clearly not ideal, but it is far less confusing then crashing because the top-level domain is not up yet. [ tglx: Added comment and a protection against chained interrupts in that context ] Signed-off-by: Marc Zyngier Cc: Yingjoe Chen Cc: Bjorn Helgaas Cc: linux-arm-kernel@lists.infradead.org Cc: Jiang Liu Link: http://lkml.kernel.org/r/1416048553-29289-3-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner

irqdomain: Introduce helper function irq_domain_add_hierarchy()

2014-11-23T12:01:46Z

Introduce helper function irq_domain_add_hierarchy(), which creates a linear irqdomain if parameter 'size' is not zero, otherwise creates a tree irqdomain. Signed-off-by: Jiang Liu Cc: Tony Luck Cc: linux-arm-kernel@lists.infradead.org Cc: Bjorn Helgaas Cc: Grant Likely Cc: Marc Zyngier Cc: Yijing Wang Cc: Yingjoe Chen Cc: Borislav Petkov Cc: Benjamin Herrenschmidt Cc: Matthias Brugger Link: http://lkml.kernel.org/r/1416061447-9472-5-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner

irqdomain: Implement a method to automatically call parent domains alloc/free

2014-11-23T12:01:46Z

Add a flags to irq_domain.flags to control whether the irqdomain core should automatically call parent irqdomain's alloc/free callbacks. It help to reduce hierarchy irqdomains users' code size. Signed-off-by: Jiang Liu Cc: Tony Luck Cc: linux-arm-kernel@lists.infradead.org Cc: Bjorn Helgaas Cc: Grant Likely Cc: Marc Zyngier Cc: Yijing Wang Cc: Yingjoe Chen Cc: Borislav Petkov Cc: Benjamin Herrenschmidt Cc: Matthias Brugger Link: http://lkml.kernel.org/r/1416061447-9472-4-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner