lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

ARM: 6834/1: perf: reset counters on all CPUs during initialisation

Browse Source 
ARMv7 dictates that the interrupt-enable and count-enable registers for
each PMU counter are UNKNOWN following core reset.

This patch adds a new (optional) function pointer to struct arm_pmu for
resetting the PMU state during init. The reset function is called on
each CPU via an arch_initcall in the generic ARM perf_event code and
allows the PMU backend to write sane values to any UNKNOWN registers.

Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon
2011-03-25 13:13:34 +01:00
committed by Russell King
parent d25d3b4c4d
commit 574b69cbb6
2 changed files with 30 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
arch/arm/kernel/perf_event.c
View File

@ -79,6 +79,7 @@ struct arm_pmu {
void (*write_counter)(int idx, u32 val);
void (*start)(void);
void (*stop)(void);
void (*reset)(void *);
const unsigned (*cache_map)[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
@ -624,6 +625,19 @@ static struct pmu pmu = {
#include "perf_event_v6.c"
#include "perf_event_v7.c"
/*
* Ensure the PMU has sane values out of reset.
* This requires SMP to be available, so exists as a separate initcall.
*/
static int __init
armpmu_reset(void)
{
if (armpmu && armpmu->reset)
return on_each_cpu(armpmu->reset, NULL, 1);
return 0;
}
arch_initcall(armpmu_reset);
static int __init
init_hw_perf_events(void)
{