kernel/arch/powerpc/sysdev/ppc4xx_msi.c, branch linux-4.1.y

powerpc/MSI: Fix race condition in tearing down MSI interrupts

2015-10-22T21:43:24Z

commit e297c939b745e420ef0b9dc989cb87bda617b399 upstream. This fixes a race which can result in the same virtual IRQ number being assigned to two different MSI interrupts. The most visible consequence of that is usually a warning and stack trace from the sysfs code about an attempt to create a duplicate entry in sysfs. The race happens when one CPU (say CPU 0) is disposing of an MSI while another CPU (say CPU 1) is setting up an MSI. CPU 0 calls (for example) pnv_teardown_msi_irqs(), which calls msi_bitmap_free_hwirqs() to indicate that the MSI (i.e. its hardware IRQ number) is no longer in use. Then, before CPU 0 gets to calling irq_dispose_mapping() to free up the virtal IRQ number, CPU 1 comes in and calls msi_bitmap_alloc_hwirqs() to allocate an MSI, and gets the same hardware IRQ number that CPU 0 just freed. CPU 1 then calls irq_create_mapping() to get a virtual IRQ number, which sees that there is currently a mapping for that hardware IRQ number and returns the corresponding virtual IRQ number (which is the same virtual IRQ number that CPU 0 was using). CPU 0 then calls irq_dispose_mapping() and frees that virtual IRQ number. Now, if another CPU comes along and calls irq_create_mapping(), it is likely to get the virtual IRQ number that was just freed, resulting in the same virtual IRQ number apparently being used for two different hardware interrupts. To fix this race, we just move the call to msi_bitmap_free_hwirqs() to after the call to irq_dispose_mapping(). Since virq_to_hw() doesn't work for the virtual IRQ number after irq_dispose_mapping() has been called, we need to call it before irq_dispose_mapping() and remember the result for the msi_bitmap_free_hwirqs() call. The pattern of calling msi_bitmap_free_hwirqs() before irq_dispose_mapping() appears in 5 places under arch/powerpc, and appears to have originated in commit 05af7bd2d75e ("[POWERPC] MPIC U3/U4 MSI backend") from 2007. Fixes: 05af7bd2d75e ("[POWERPC] MPIC U3/U4 MSI backend") Reported-by: Alexey Kardashevskiy Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2014-12-15T00:10:09Z

Pull driver core update from Greg KH: "Here's the set of driver core patches for 3.19-rc1. They are dominated by the removal of the .owner field in platform drivers. They touch a lot of files, but they are "simple" changes, just removing a line in a structure. Other than that, a few minor driver core and debugfs changes. There are some ath9k patches coming in through this tree that have been acked by the wireless maintainers as they relied on the debugfs changes. Everything has been in linux-next for a while" * tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits) Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries" fs: debugfs: add forward declaration for struct device type firmware class: Deletion of an unnecessary check before the function call "vunmap" firmware loader: fix hung task warning dump devcoredump: provide a one-way disable function device: Add dev__once variants ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries ath: use seq_file api for ath9k debugfs files debugfs: add helper function to create device related seq_file drivers/base: cacheinfo: remove noisy error boot message Revert "core: platform: add warning if driver has no owner" drivers: base: support cpu cache information interface to userspace via sysfs drivers: base: add cpu_device_create to support per-cpu devices topology: replace custom attribute macros with standard DEVICE_ATTR* cpumask: factor out show_cpumap into separate helper function driver core: Fix unbalanced device reference in drivers_probe driver core: fix race with userland in device_add() sysfs/kernfs: make read requests on pre-alloc files use the buffer. sysfs/kernfs: allow attributes to request write buffer be pre-allocated. fs: sysfs: return EGBIG on write if offset is larger than file size ...

Merge tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

2014-12-12T01:48:14Z

Pull powerpc updates from Michael Ellerman: "Some nice cleanups like removing bootmem, and removal of __get_cpu_var(). There is one patch to mm/gup.c. This is the generic GUP implementation, but is only used by us and arm(64). We have an ack from Steve Capper, and although we didn't get an ack from Andrew he told us to take the patch through the powerpc tree. There's one cxl patch. This is in drivers/misc, but Greg said he was happy for us to manage fixes for it. There is an infrastructure patch to support an IPMI driver for OPAL. There is also an RTC driver for OPAL. We weren't able to get any response from the RTC maintainer, Alessandro Zummo, so in the end we just merged the driver. The usual batch of Freescale updates from Scott" * tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (101 commits) powerpc/powernv: Return to cpu offline loop when finished in KVM guest powerpc/book3s: Fix partial invalidation of TLBs in MCE code. powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault powerpc/xmon: Cleanup the breakpoint flags powerpc/xmon: Enable HW instruction breakpoint on POWER8 powerpc/mm/thp: Use tlbiel if possible powerpc/mm/thp: Remove code duplication powerpc/mm/hugetlb: Sanity check gigantic hugepage count powerpc/oprofile: Disable pagefaults during user stack read powerpc/mm: Check for matching hpte without taking hpte lock powerpc: Drop useless warning in eeh_init() powerpc/powernv: Cleanup unused MCE definitions/declarations. powerpc/eeh: Dump PHB diag-data early powerpc/eeh: Recover EEH error on ownership change for BCM5719 powerpc/eeh: Set EEH_PE_RESET on PE reset powerpc/eeh: Refactor eeh_reset_pe() powerpc: Remove more traces of bootmem powerpc/pseries: Initialise nvram_pstore_info's buf_lock cxl: Name interrupts in /proc/interrupt cxl: Return error to PSL if IRQ demultiplexing fails & print clearer warning ...

PCI/MSI: Rename write_msi_msg() to pci_write_msi_msg()

2014-11-23T12:01:45Z

Rename write_msi_msg() to pci_write_msi_msg() to mark it as PCI specific. 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

powerpc: Remove superfluous bootmem includes

2014-11-09T22:59:26Z

Lots of places included bootmem.h even when not using bootmem. Signed-off-by: Anton Blanchard Tested-by: Emil Medve Signed-off-by: Michael Ellerman

powerpc: sysdev: drop owner assignment from platform_drivers

2014-10-20T14:20:13Z

A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang

PCI/MSI/PPC: Remove arch_msi_check_device()

2014-10-01T18:21:14Z

Move MSI checks from arch_msi_check_device() to arch_setup_msi_irqs(). This makes the code more compact and allows removing arch_msi_check_device() from generic MSI code. Signed-off-by: Alexander Gordeev Signed-off-by: Bjorn Helgaas Acked-by: Michael Ellerman

POWERPC: drivers: remove __dev* attributes.

2013-01-03T23:57:04Z

CONFIG_HOTPLUG is going away as an option. As a result, the __dev* markings need to be removed. This change removes the use of __devinit, __devexit_p, __devinitdata, __devinitconst, and __devexit from these drivers. Based on patches originally written by Bill Pemberton, but redone by me in order to handle some of the coding style issues better, by hand. Cc: Bill Pemberton Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Signed-off-by: Greg Kroah-Hartman

powerpc/40x: Use {upper,lower}_32_bits for msi_phys

2012-05-04T00:13:13Z

Fix a build error when -Werror is set: arch/powerpc/sysdev/ppc4xx_msi.c: In function ‘ppc4xx_setup_pcieh_hw’: arch/powerpc/sysdev/ppc4xx_msi.c:178:2: error: right shift count >= width of type [-Werror] Signed-off-by: Josh Boyer

powerpc/44x: Fix PCI MSI support for Maui APM821xx SoC and Bluestone board

2012-05-03T12:49:31Z

This patch consists of: - Enable PCI MSI as default for Bluestone board - Change definition of number of MSI interrupts as it depends on SoC - Fix returning ENODEV as finding MSI node - Fix MSI physical high and low address - Keep MSI data logically Signed-off-by: Mai La Signed-off-by: Josh Boyer