linux.git/arch/powerpc/sysdev/fsl_msi.c, branch v3.12.65

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

2015-10-05T20:02:56+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: Paul Mackerras 
Signed-off-by: Jiri Slaby

powerpc/fsl_msi: add MSIIR1 support for MPIC v4.3

2013-08-07T23:38:05+00:00

The original MPIC MSI bank contains 8 registers, MPIC v4.3 MSI bank
contains 16 registers, and this patch adds NR_MSI_REG_MAX and
NR_MSI_IRQS_MAX to describe the maximum capability of MSI bank.
MPIC v4.3 provides MSIIR1 to index these 16 MSI registers. MSIIR1
uses different bits definition than MSIIR. This patch adds
ibs_shift and srs_shift to indicate the bits definition of the
MSIIR and MSIIR1, so the same code can handle the MSIIR and MSIIR1
simultaneously.

Signed-off-by: Minghuan Lian 
[scottwood@freescale.com: reinstated static on all_avail]
Signed-off-by: Scott Wood

powerpc/fsl_msi: fix error return code in fsl_of_msi_probe()

2013-07-30T20:50:08+00:00

Fix to return a negative error code in the MSI bitmap alloc error
handling case instead of 0, as done elsewhere in this function.

Signed-off-by: Wei Yongjun 
Signed-off-by: Scott Wood

powerpc/fsl-msi: use a different lockclass for the cascade interrupt

2013-04-03T16:42:48+00:00

lockdep thinks that it might deadlock because it grabs a lock of the
same class while calling the generic_irq_handler(). This annotation will
inform lockdep that it will not.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Kumar Gala

powerpc/fsl: msi: sparse fixes

2013-02-12T17:05:23+00:00

arch/powerpc/sysdev/fsl_msi.c:31:1: warning: symbol 'msi_head' was not declared. Should it be static?
arch/powerpc/sysdev/fsl_msi.c:138:40: warning: incorrect type in argument 1 (different base types)
arch/powerpc/sysdev/fsl_msi.c:138:40:    expected restricted __be64 const [usertype] *p
arch/powerpc/sysdev/fsl_msi.c:138:40:    got unsigned long long const [usertype] *[assigned] reg

Signed-off-by: Kim Phillips 
Signed-off-by: Kumar Gala

POWERPC: drivers: remove __dev* attributes.

2013-01-03T23:57:04+00:00

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

Merge branch 'for-upstream' of http://github.com/agraf/linux-2.6 into queue

2012-10-10T22:03:54+00:00

* 'for-upstream' of http://github.com/agraf/linux-2.6: (56 commits)
  arch/powerpc/kvm/e500_tlb.c: fix error return code
  KVM: PPC: Book3S HV: Provide a way for userspace to get/set per-vCPU areas
  KVM: PPC: Book3S: Get/set guest FP regs using the GET/SET_ONE_REG interface
  KVM: PPC: Book3S: Get/set guest SPRs using the GET/SET_ONE_REG interface
  KVM: PPC: set IN_GUEST_MODE before checking requests
  KVM: PPC: e500: MMU API: fix leak of shared_tlb_pages
  KVM: PPC: e500: fix allocation size error on g2h_tlb1_map
  KVM: PPC: Book3S HV: Fix calculation of guest phys address for MMIO emulation
  KVM: PPC: Book3S HV: Remove bogus update of physical thread IDs
  KVM: PPC: Book3S HV: Fix updates of vcpu->cpu
  KVM: Move some PPC ioctl definitions to the correct place
  KVM: PPC: Book3S HV: Handle memory slot deletion and modification correctly
  KVM: PPC: Move kvm->arch.slot_phys into memslot.arch
  KVM: PPC: Book3S HV: Take the SRCU read lock before looking up memslots
  KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
  KVM: PPC: BookE: Support FPU on non-hv systems
  KVM: PPC: 440: Implement mfdcrx
  KVM: PPC: 440: Implement mtdcrx
  Document IACx/DACx registers access using ONE_REG API
  KVM: PPC: E500: Remove E500_TLB_DIRTY flag
  ...

powerpc/fsl-soc: use CONFIG_EPAPR_PARAVIRT for hcalls

2012-10-05T21:38:38+00:00

Signed-off-by: Scott Wood 
Signed-off-by: Stuart Yoder 
Signed-off-by: Alexander Graf

powerpc/fsl_msi: drop unneeded cast to non-const pointer

2012-09-11T06:57:28+00:00

This cast is unneeded since *of_device_id.data became const.

[ukl: split Arnd's patch by driver and add changelog]

Signed-off-by: Arnd Bergmann 
Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Uwe Kleine-König

powerpc/fsl_msi: add a const qualifier

2012-09-11T06:57:09+00:00

This prepares *of_device_id.data becoming const. Without this change
the following warning would occur:

	arch/powerpc/sysdev/fsl_msi.c: In function 'fsl_of_msi_probe':
	arch/powerpc/sysdev/fsl_msi.c:379:11: error: assignment discards 'const' qualifier from pointer target type [-Werror]

Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Uwe Kleine-König