linux-toradex.git/arch/powerpc/sysdev/mpic_u3msi.c, branch v4.2.7

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

2015-10-22T21:49:31+00:00

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

powerpc/mpic_u3msi: Move MSI-related ops to pci_controller_ops

2015-06-02T01:47:44+00:00

Move the u3 MPIC msi subsystem to use the pci_controller_ops structure
rather than ppc_md for MSI related PCI controller operations.

As with fsl_msi, operations are plugged in at the subsys level, after
controller creation. Again, we iterate over all controllers and
populate them with the MSI ops.

Signed-off-by: Daniel Axtens 
Signed-off-by: Michael Ellerman

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

2014-12-12T01:48:14+00:00

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 mask/unmask_msi_irq treewide

2014-11-23T12:01:45+00:00

The PCI/MSI irq chip callbacks mask/unmask_msi_irq have been renamed
to pci_msi_mask/unmask_irq to mark them PCI specific. Rename all usage
sites. The conversion helper functions are kept around to avoid
conflicts in next and will be removed after merging into mainline.

Coccinelle assisted conversion. No functional change.

Signed-off-by: Thomas Gleixner 
Cc: Bjorn Helgaas 
Cc: Russell King 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Heiko Carstens 
Cc: "David S. Miller" 
Cc: Chris Metcalf 
Cc: x86@kernel.org
Cc: Jiang Liu 
Cc: Jason Cooper 
Cc: Murali Karicheri 
Cc: Thierry Reding 
Cc: Mohit Kumar 
Cc: Simon Horman 
Cc: Michal Simek 
Cc: Yijing Wang

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

2014-11-23T12:01:45+00:00

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

2014-11-09T22:59:26+00:00

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

PCI/MSI/PPC: Remove arch_msi_check_device()

2014-10-01T18:21:14+00:00

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: Convert to new irq_* function names

2011-03-29T12:48:12+00:00

Scripted with coccinelle.

Signed-off-by: Thomas Gleixner

powerpc: mpic irq_data conversion.

2011-03-10T00:03:56+00:00

Signed-off-by: Lennert Buytenhek 
Signed-off-by: Benjamin Herrenschmidt

pci: Convert msi to new irq_chip functions

2010-10-12T14:53:34+00:00

Signed-off-by: Thomas Gleixner 
Reviewed-by: Ingo Molnar 
Acked-by: Jesse Barnes 
Cc: Benjamin Herrenschmidt 
Cc: "David S. Miller" 
Cc: Tony Luck 
Cc: Russell King