linux-toradex.git/arch/arm/kernel/ptrace.c, branch v3.2.20

ARM: 7308/1: vfp: flush thread hwstate before copying ptrace registers

2012-02-13T19:16:52+00:00

commit 8130b9d7b9d858aa04ce67805e8951e3cb6e9b2f upstream.

If we are context switched whilst copying into a thread's
vfp_hard_struct then the partial copy may be corrupted by the VFP
context switching code (see "ARM: vfp: flush thread hwstate before
restoring context from sigframe").

This patch updates the ptrace VFP set code so that the thread state is
flushed before the copy, therefore disabling VFP and preventing
corruption from occurring.

Signed-off-by: Will Deacon 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: 7307/1: vfp: fix ptrace regset modification race

2012-02-13T19:16:52+00:00

commit 247f4993a5974e6759606c4d380748eecfd273ff upstream.

In a preemptible kernel, vfp_set() can be preempted, causing the
hardware VFP context to be switched while the thread vfp state is
being read and modified.  This leads to a race condition which can
cause the thread vfp state to become corrupted if lazy VFP context
save occurs due to preemption in between the time thread->vfpstate
is read and the time the modified state is written back.

This may occur if preemption occurs during the execution of a
ptrace() call which modifies the VFP register state of a thread.
Such instances should be very rare in most realistic scenarios --
none has been reported, so far as I am aware.  Only uniprocessor
systems should be affected, since VFP context save is not currently
lazy in SMP kernels.

The problem was introduced by my earlier patch migrating to use
regsets to implement ptrace.

This patch does a vfp_sync_hwstate() before reading
thread->vfpstate, to make sure that the thread's VFP state is not
live in the hardware registers while the registers are modified.

Thanks to Will Deacon for spotting this.

Signed-off-by: Dave Martin 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

arm: add elf.h to arch/arm/kernel/ptrace.c

2011-10-31T23:30:45+00:00

It was implicitly getting it via an implicit presence of module.h
but when we clean that up, we'll get a bunch of lines like this:

arch/arm/kernel/ptrace.c:764: error: 'NT_PRSTATUS' undeclared here (not in a function)
arch/arm/kernel/ptrace.c:765: error: 'ELF_NGREG' undeclared here (not in a function)
arch/arm/kernel/ptrace.c:776: error: 'NT_PRFPREG' undeclared here (not in a function)

Signed-off-by: Paul Gortmaker

Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm

2011-07-24T17:20:54+00:00

* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (237 commits)
  ARM: 7004/1: fix traps.h compile warnings
  ARM: 6998/2: kernel: use proper memory barriers for bitops
  ARM: 6997/1: ep93xx: increase NR_BANKS to 16 for support of 128MB RAM
  ARM: Fix build errors caused by adding generic macros
  ARM: CPU hotplug: ensure we migrate all IRQs off a downed CPU
  ARM: CPU hotplug: pass in proper affinity mask on IRQ migration
  ARM: GIC: avoid routing interrupts to offline CPUs
  ARM: CPU hotplug: fix abuse of irqdesc->node
  ARM: 6981/2: mmci: adjust calculation of f_min
  ARM: 7000/1: LPAE: Use long long printk format for displaying the pud
  ARM: 6999/1: head, zImage: Always Enter the kernel in ARM state
  ARM: btc: avoid invalidating the branch target cache on kernel TLB maintanence
  ARM: ARM_DMA_ZONE_SIZE is no more
  ARM: mach-shark: move ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-sa1100: move ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-realview: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-pxa: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-ixp4xx: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-h720x: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ARM: mach-davinci: move from ARM_DMA_ZONE_SIZE to mdesc->dma_zone_size
  ...

ARM: Thumb-2: Support Thumb-2 in undefined instruction handler

2011-07-13T17:32:40+00:00

This patch allows undef_hook's to be specified for 32-bit Thumb
instructions and also to be used for thumb kernel-side code.

32-bit Thumb instructions are specified in the form:
	((first_half << 16 ) | second_half)
which matches the layout used by the ARM ARM.

ptrace was handling 32-bit Thumb instructions by hooking the first
halfword and manually checking the second half. This method would be
broken by this patch so it is migrated to make use of the new Thumb-2
support.

Signed-off-by: Jon Medhurst 
Acked-by: Nicolas Pitre

perf: Add context field to perf_event

2011-07-01T09:06:38+00:00

The perf_event overflow handler does not receive any caller-derived
argument, so many callers need to resort to looking up the perf_event
in their local data structure.  This is ugly and doesn't scale if a
single callback services many perf_events.

Fix by adding a context parameter to perf_event_create_kernel_counter()
(and derived hardware breakpoints APIs) and storing it in the perf_event.
The field can be accessed from the callback as event->overflow_handler_context.
All callers are updated.

Signed-off-by: Avi Kivity 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar

perf: Remove the nmi parameter from the swevent and overflow interface

2011-07-01T09:06:35+00:00

The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.

For the various event classes:

  - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
    the PMI-tail (ARM etc.)
  - tracepoint: nmi=0; since tracepoint could be from NMI context.
  - software: nmi=[0,1]; some, like the schedule thing cannot
    perform wakeups, and hence need 0.

As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).

The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.

Signed-off-by: Peter Zijlstra 
Cc: Michael Cree 
Cc: Will Deacon 
Cc: Deng-Cheng Zhu 
Cc: Anton Blanchard 
Cc: Eric B Munson 
Cc: Heiko Carstens 
Cc: Paul Mundt 
Cc: David S. Miller 
Cc: Frederic Weisbecker 
Cc: Jason Wessel 
Cc: Don Zickus 
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org
Signed-off-by: Ingo Molnar

ARM: 6883/1: ptrace: Migrate to regsets framework

2011-05-14T20:36:55+00:00

This patch migrates the implementation of the ptrace interface for
the core integer registers, legacy FPA registers and VFP registers
to use the regsets framework.

As an added bonus, all this stuff gets included in coredumps
at no extra cost.  Without this patch, coredumps contained no
VFP state.

Third-party extension register sets (iwmmx, crunch) are not migrated
by this patch, and continue to use the old implementation;
these should be migratable without much extra work.

Signed-off-by: Dave Martin 
Acked-by: Will Deacon 
Signed-off-by: Russell King

arm, hw_breakpoints: Fix racy access to ptrace breakpoints

2011-04-25T15:35:18+00:00

While the tracer accesses ptrace breakpoints, the child task may
concurrently exit due to a SIGKILL and thus release its breakpoints
at the same time. We can then dereference some freed pointers.

To fix this, hold a reference on the child breakpoints before
manipulating them.

Reported-by: Oleg Nesterov 
Signed-off-by: Frederic Weisbecker 
Acked-by: Will Deacon 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Prasad 
Cc: Paul Mundt 
Link: http://lkml.kernel.org/r/1302284067-7860-5-git-send-email-fweisbec@gmail.com

Merge branch 'misc' into devel

2011-03-16T23:35:25+00:00

Conflicts:
	arch/arm/Kconfig