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  1. 18 5月, 2012 37 次提交
  3. 17 5月, 2012 3 次提交
    • W
      ARM: 7419/1: vfp: fix VFP flushing regression on sigreturn path · 56cb2484
      由 Will Deacon 提交于 
      Commit ff9a184c ("ARM: 7400/1: vfp: clear fpscr length and stride bits
on entry to sig handler") flushes the VFP state prior to entering a
signal handler so that a VFP operation inside the handler will trap and
force a restore of ABI-compliant registers. Reflushing and disabling VFP
on the sigreturn path is predicated on the saved thread state indicating
that VFP was used by the handler -- however for SMP platforms this is
only set on context-switch, making the check unreliable and causing VFP
register corruption in userspace since the register values are not
necessarily those restored from the sigframe.

This patch unconditionally flushes the VFP state after a signal handler.
Since we already perform the flush before the handler and the flushing
itself happens lazily, the redundant flush when VFP is not used by the
handler is essentially a nop.
Reported-by: NJon Medhurst <tixy@linaro.org>
Signed-off-by: NJon Medhurst <tixy@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      56cb2484
    • V
      ARM: 7418/1: LPAE: fix access flag setup in mem_type_table · 1a3abcf4
      由 Vitaly Andrianov 提交于 
      A zero value for prot_sect in the memory types table implies that
section mappings should never be created for the memory type in question.
This is checked for in alloc_init_section().

With LPAE, we set a bit to mask access flag faults for kernel mappings.
This breaks the aforementioned (!prot_sect) check in alloc_init_section().

This patch fixes this bug by first checking for a non-zero
prot_sect before setting the PMD_SECT_AF flag.
Signed-off-by: NVitaly Andrianov <vitalya@ti.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      1a3abcf4
    • M
      virtio_net: invoke softirqs after __napi_schedule · ec13ee80
      由 Michael S. Tsirkin 提交于 
      __napi_schedule might raise softirq but nothing
causes do_softirq to trigger, so it does not in fact
run. As a result,
the error message "NOHZ: local_softirq_pending 08"
sometimes occurs during boot of a KVM guest when the network service is
started and we are oom:

  ...
  Bringing up loopback interface:  [  OK  ]
  Bringing up interface eth0:
  Determining IP information for eth0...NOHZ: local_softirq_pending 08
   done.
  [  OK  ]
  ...

Further, receive queue processing might get delayed
indefinitely until some interrupt triggers:
virtio_net expected napi to be run immediately.

One way to cause do_softirq to be executed is by
invoking local_bh_enable(). As __napi_schedule is
normally called from bh or irq context, this
seems to make sense: disable bh before __napi_schedule
and enable afterwards.

In fact it's a very complicated way of calling do_softirq(),
and works since this function is only used when we are not
in interrupt context.  It's not hot at all, in any ideal scenario.
Reported-by: NUlrich Obergfell <uobergfe@redhat.com>
Tested-by: NUlrich Obergfell <uobergfe@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
      ec13ee80