linux-toradex.git/arch/arm64/kernel/debug-monitors.c, branch v3.16.5

arm64: don't call break hooks for BRK exceptions from EL0

2014-09-05T23:36:28+00:00

commit c878e0cff5c5e56b216951cbe75f7a3dd500a736 upstream.

Our break hooks are used to handle brk exceptions from kgdb (and potentially
kprobes if that code ever resurfaces), so don't bother calling them if
the BRK exception comes from userspace.

This prevents userspace from trapping to a kdb shell on systems where
kgdb is enabled and active.

Reported-by: Omar Sandoval 
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

arm64: debug: remove noisy, pointless warning

2014-04-25T15:46:50+00:00

Sending a SIGTRAP to a user task after execution of a BRK instruction at
EL0 is fundamental to the way in which software breakpoints work and
doesn't deserve a warning to be logged in dmesg. Whilst the warning can
be justified from EL1, do_debug_exception will already do the right thing,
so simply remove the code altogether.

Cc: Sandeepa Prabhu 
Reported-by: Kyrylo Tkachov 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas

Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2014-04-07T21:55:46+00:00

Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
 "The purpose of this single series of commits from Srivatsa S Bhat
  (with a small piece from Gautham R Shenoy) touching multiple
  subsystems that use CPU hotplug notifiers is to provide a way to
  register them that will not lead to deadlocks with CPU online/offline
  operations as described in the changelog of commit 93ae4f978ca7f ("CPU
  hotplug: Provide lockless versions of callback registration
  functions").

  The first three commits in the series introduce the API and document
  it and the rest simply goes through the users of CPU hotplug notifiers
  and converts them to using the new method"

* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
  net/iucv/iucv.c: Fix CPU hotplug callback registration
  net/core/flow.c: Fix CPU hotplug callback registration
  mm, zswap: Fix CPU hotplug callback registration
  mm, vmstat: Fix CPU hotplug callback registration
  profile: Fix CPU hotplug callback registration
  trace, ring-buffer: Fix CPU hotplug callback registration
  xen, balloon: Fix CPU hotplug callback registration
  hwmon, via-cputemp: Fix CPU hotplug callback registration
  hwmon, coretemp: Fix CPU hotplug callback registration
  thermal, x86-pkg-temp: Fix CPU hotplug callback registration
  octeon, watchdog: Fix CPU hotplug callback registration
  oprofile, nmi-timer: Fix CPU hotplug callback registration
  intel-idle: Fix CPU hotplug callback registration
  clocksource, dummy-timer: Fix CPU hotplug callback registration
  drivers/base/topology.c: Fix CPU hotplug callback registration
  acpi-cpufreq: Fix CPU hotplug callback registration
  zsmalloc: Fix CPU hotplug callback registration
  scsi, fcoe: Fix CPU hotplug callback registration
  scsi, bnx2fc: Fix CPU hotplug callback registration
  scsi, bnx2i: Fix CPU hotplug callback registration
  ...

arm64, debug-monitors: Fix CPU hotplug callback registration

2014-03-20T12:43:44+00:00

Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Instead, the correct and race-free way of performing the callback
registration is:

	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	/* Note the use of the double underscored version of the API */
	__register_cpu_notifier(&foobar_cpu_notifier);

	cpu_notifier_register_done();

Fix the debug-monitors code in arm64 by using this latter form of callback
registration.

Cc: Catalin Marinas 
Cc: Russell King 
Cc: Ingo Molnar 
Acked-by: Will Deacon 
Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Rafael J. Wysocki

arm64: debug: make local symbols static

2014-03-13T11:22:39+00:00

Make local symbols static, because these are used only in this
file.

Signed-off-by: Jingoo Han 
Signed-off-by: Catalin Marinas

arm64: enable processor debug state for secondary cpus

2014-02-26T11:16:27+00:00

processor debug state PSTATE.D is unmasked in smp call
clear_os_lock for secondary cpus. So debug state is still
masked in normal kernel context.  With this patch, unmask
debug state on secondary boot for the cpus in normal kernel
context. Now kgdb tests passed with multicore.

Signed-off-by: Vijaya Kumar K 
Acked-by: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: Add macros to manage processor debug state

2014-02-26T11:16:25+00:00

Add macros to enable and disable to manage PSTATE.D
for debugging. The macros local_dbg_save and local_dbg_restore
are moved to irqflags.h file

KGDB boot tests fail because of PSTATE.D is masked.
unmask it for debugging support

Signed-off-by: Vijaya Kumar K 
Acked-by: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: support single-step and breakpoint handler hooks

2013-12-19T17:43:11+00:00

AArch64 Single Steping and Breakpoint debug exceptions will be
used by multiple debug framworks like kprobes & kgdb.

This patch implements the hooks for those frameworks to register
their own handlers for handling breakpoint and single step events.

Reworked the debug exception handler in entry.S: do_dbg to route
software breakpoint (BRK64) exception to do_debug_exception()

Signed-off-by: Sandeepa Prabhu 
Signed-off-by: Deepak Saxena 
Acked-by: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: debug: make aarch32 bkpt checking endian clean

2013-11-28T18:01:29+00:00

The current breakpoint instruction checking code for A32 is not endian
clean. Fix this with appropriate byte-swapping when retrieving
instructions.

Signed-off-by: Matthew Leach 
Reviewed-by: Will Deacon 
Signed-off-by: Catalin Marinas

ARM: 7862/1: pcpu: replace __get_cpu_var_uses

2013-10-29T11:06:27+00:00

This is the ARM part of Christoph's patchset cleaning up the various
uses of __get_cpu_var across the tree.

The idea is to convert __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations
that use the offset. Thereby address calculations are avoided and fewer
registers are used when code is generated.

[will: fixed debug ref counting checks and pcpu array accesses]

Acked-by: Catalin Marinas 
Signed-off-by: Christoph Lameter 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King