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[PATCH] ppc64: fix oprofile sample bit handling 

Oprofile was hardwiring the MMCRA sample bit to 1 but on newer cpus
(eg POWER5) we want to vary it based on the group being sampled.

Add a temporary workaround until people update their oprofile userspace.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Anton Blanchard 2005-11-07 18:43:56 +11:00 committed by Paul Mackerras
parent bcb3557694
commit cb09cff30a
1 changed files with 23 additions and 1 deletions
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24
arch/powerpc/oprofile/op_model_power4.c
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@ -17,6 +17,7 @@
#include <asm/systemcfg.h>
#include <asm/rtas.h>
#include <asm/oprofile_impl.h>
#include <asm/reg.h>
#define dbg(args...)
@ -81,6 +82,26 @@ static void power4_reg_setup(struct op_counter_config *ctr,
extern void ppc64_enable_pmcs(void);
/*
* Older CPUs require the MMCRA sample bit to be always set, but newer
* CPUs only want it set for some groups. Eventually we will remove all
* knowledge of this bit in the kernel, oprofile userspace should be
* setting it when required.
*
* In order to keep current installations working we force the bit for
* those older CPUs. Once everyone has updated their oprofile userspace we
* can remove this hack.
*/
static inline int mmcra_must_set_sample(void)
{
if (__is_processor(PV_POWER4) || __is_processor(PV_POWER4p) ||
__is_processor(PV_970) || __is_processor(PV_970FX) ||
__is_processor(PV_970MP))
return 1;
return 0;
}
static void power4_cpu_setup(void *unused)
{
unsigned int mmcr0 = mmcr0_val;
@ -98,7 +119,8 @@ static void power4_cpu_setup(void *unused)
mtspr(SPRN_MMCR1, mmcr1_val);
mmcra |= MMCRA_SAMPLE_ENABLE;
if (mmcra_must_set_sample())
mmcra |= MMCRA_SAMPLE_ENABLE;
mtspr(SPRN_MMCRA, mmcra);
dbg("setup on cpu %d, mmcr0 %lx\n", smp_processor_id(),