We should use perf_sample_data_init() to initialize struct
perf_sample_data. As explained in the description of commit dc1d628a
("perf: Provide generic perf_sample_data initialization"), it is
possible for userspace to get the kernel to dereference data.raw,
so if it is not initialized, that means that unprivileged userspace
can possibly oops the kernel. Using perf_sample_data_init makes sure
it gets initialized to NULL.
This conversion should have been included in commit dc1d628a, but it
got missed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This implements perf_event support for the Freescale embedded performance
monitor, based on the existing perf_event.c that supports server/classic
chips.
Some limitations:
- Performance monitor interrupts are regular EE interrupts, and thus you
can't profile places with interrupts disabled. We may want to implement
soft IRQ-disabling, with perfmon interrupts exempted and treated as NMIs.
- When trying to schedule multiple event groups at once, and using
restricted events, situations could arise where scheduling fails even
though it would be possible. Consider three groups, each with two events.
One group has restricted events, the others don't. The two non-restricted
groups are scheduled, then one is removed, which happens to occupy the two
counters that can't do restricted events. The remaining non-restricted
group will not be moved to the non-restricted-capable counters to make
room if the restricted group tries to be scheduled.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
