linux-toradex.git/kernel/events/hw_breakpoint.c, branch v4.2.5

perf: Remove type specific target pointers

2015-03-23T09:58:04+00:00

The only reason CQM had to use a hard-coded pmu type was so it could use
cqm_target in hw_perf_event.

Do away with the {tp,bp,cqm}_target pointers and provide a non type
specific one.

This allows us to do away with that silly pmu type as well.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Vince Weaver 
Cc: acme@kernel.org
Cc: acme@redhat.com
Cc: hpa@zytor.com
Cc: jolsa@redhat.com
Cc: kanaka.d.juvva@intel.com
Cc: matt.fleming@intel.com
Cc: tglx@linutronix.de
Cc: torvalds@linux-foundation.org
Cc: vikas.shivappa@linux.intel.com
Link: http://lkml.kernel.org/r/20150305211019.GU21418@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar

perf: Fix and clean up initialization of pmu::event_idx

2014-10-28T09:51:01+00:00

Andy reported that the current state of event_idx is rather confused.
So remove all but the x86_pmu implementation and change the default to
return 0 (the safe option).

Reported-by: Andy Lutomirski 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Arnaldo Carvalho de Melo 
Cc: Benjamin Herrenschmidt 
Cc: Christoph Lameter 
Cc: Cody P Schafer 
Cc: Cody P Schafer 
Cc: Heiko Carstens 
Cc: Hendrik Brueckner 
Cc: Himangi Saraogi 
Cc: Linus Torvalds 
Cc: Martin Schwidefsky 
Cc: Michael Ellerman 
Cc: Paul Gortmaker 
Cc: Paul Mackerras 
Cc: sukadev@linux.vnet.ibm.com 
Cc: Thomas Huth 
Cc: Vince Weaver 
Cc: linux390@de.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Signed-off-by: Ingo Molnar

hw_breakpoint: Introduce "struct bp_cpuinfo"

2013-06-20T15:58:57+00:00

This patch simply moves all per-cpu variables into the new
single per-cpu "struct bp_cpuinfo".

To me this looks more logical and clean, but this can also
simplify the further potential changes. In particular, I do not
think this memory should be per-cpu, it is never used "locally".
After this change it is trivial to turn it into, say,
bootmem[nr_cpu_ids].

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20130620155020.GA6350@redhat.com
Signed-off-by: Ingo Molnar

hw_breakpoint: Simplify *register_wide_hw_breakpoint()

2013-06-20T15:58:57+00:00

1. register_wide_hw_breakpoint() can use unregister_ if failure,
   no need to duplicate the code.

2. "struct perf_event **pevent" adds the unnecesary lever of
   indirection and complication, use per_cpu(*cpu_events, cpu).

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20130620155018.GA6347@redhat.com
Signed-off-by: Ingo Molnar

hw_breakpoint: Introduce cpumask_of_bp()

2013-06-20T15:58:56+00:00

Add the trivial helper which simply returns cpumask_of() or
cpu_possible_mask depending on bp->cpu.

Change fetch_bp_busy_slots() and toggle_bp_slot() to always do
for_each_cpu(cpumask_of_bp) to simplify the code and avoid the
code duplication.

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20130620155015.GA6340@redhat.com
Signed-off-by: Ingo Molnar

hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() paths

2013-06-20T15:58:55+00:00

Change toggle_bp_slot() to make "weight" negative if !enable.
This way we can always use "+ weight" without additional "if
(enable)" check and toggle_bp_task_slot() no longer needs this
arg.

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20130620155013.GA6337@redhat.com
Signed-off-by: Ingo Molnar

hw_breakpoint: Simplify list/idx mess in toggle_bp_slot() paths

2013-06-20T15:58:55+00:00

The enable/disable logic in toggle_bp_slot() is not symmetrical
and imho very confusing. "old_count" in toggle_bp_task_slot() is
actually new_count because this bp was already removed from the
list.

Change toggle_bp_slot() to always call list_add/list_del after
toggle_bp_task_slot(). This way old_idx is task_bp_pinned() and
this entry should be decremented, new_idx is +/-weight and we
need to increment this element. The code/logic looks obvious.

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20130620155011.GA6330@redhat.com
Signed-off-by: Ingo Molnar

Merge branch 'perf/urgent' into perf/core

2013-06-20T15:57:40+00:00

Merge in two hw_breakpoint fixes, before applying another 5.

Signed-off-by: Ingo Molnar

hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()

2013-06-20T15:57:01+00:00

fetch_bp_busy_slots() and toggle_bp_slot() use
for_each_online_cpu(), this is obviously wrong wrt cpu_up() or
cpu_down(), we can over/under account the per-cpu numbers.

For example:

	# echo 0 >> /sys/devices/system/cpu/cpu1/online
	# perf record -e mem:0x10 -p 1 &
	# echo 1 >> /sys/devices/system/cpu/cpu1/online
	# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a &
	# taskset -p 0x2 1

triggers the same WARN_ONCE("Can't find any breakpoint slot") in
arch_install_hw_breakpoint().

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Cc: 
Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com
Signed-off-by: Ingo Molnar

hw_breakpoint: Fix cpu check in task_bp_pinned(cpu)

2013-06-20T15:57:00+00:00

trinity fuzzer triggered WARN_ONCE("Can't find any breakpoint
slot") in arch_install_hw_breakpoint() but the problem is not
arch-specific.

The problem is, task_bp_pinned(cpu) checks "cpu == iter->cpu"
but this doesn't account the "all cpus" events with iter->cpu <
0.

This means that, say, register_user_hw_breakpoint(tsk) can
happily create the arbitrary number > HBP_NUM of breakpoints
which can not be activated. toggle_bp_task_slot() is equally
wrong by the same reason and nr_task_bp_pinned[] can have
negative entries.

Simple test:

	# perl -e 'sleep 1 while 1' &
	# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10,mem:0x10 -p `pidof perl`

Before this patch this triggers the same problem/WARN_ON(),
after the patch it correctly fails with -ENOSPC.

Reported-by: Vince Weaver 
Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Cc: 
Link: http://lkml.kernel.org/r/20130620155006.GA6324@redhat.com
Signed-off-by: Ingo Molnar