mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 21:57:43 +00:00
ffb20c2e52
In some cases, when probing a perf MSR, we're probing certain bits of the MSR instead of the whole register, thus only these bits should be checked. For example, for RAPL ENERGY_STATUS MSR, only the lower 32 bits represents the energy counter, and the higher 32bits are reserved. Introduce a new mask field in struct perf_msr to allow probing certain bits of a MSR. This change is transparent to the current perf_msr_probe() users. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Andi Kleen <ak@linux.intel.com> Link: https://lkml.kernel.org/r/20210204161816.12649-1-rui.zhang@intel.com
63 lines
1.3 KiB
C
63 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/export.h>
|
|
#include <linux/types.h>
|
|
#include <linux/bits.h>
|
|
#include "probe.h"
|
|
|
|
static umode_t
|
|
not_visible(struct kobject *kobj, struct attribute *attr, int i)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Accepts msr[] array with non populated entries as long as either
|
|
* msr[i].msr is 0 or msr[i].grp is NULL. Note that the default sysfs
|
|
* visibility is visible when group->is_visible callback is set.
|
|
*/
|
|
unsigned long
|
|
perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
|
|
{
|
|
unsigned long avail = 0;
|
|
unsigned int bit;
|
|
u64 val;
|
|
|
|
if (cnt >= BITS_PER_LONG)
|
|
return 0;
|
|
|
|
for (bit = 0; bit < cnt; bit++) {
|
|
if (!msr[bit].no_check) {
|
|
struct attribute_group *grp = msr[bit].grp;
|
|
u64 mask;
|
|
|
|
/* skip entry with no group */
|
|
if (!grp)
|
|
continue;
|
|
|
|
grp->is_visible = not_visible;
|
|
|
|
/* skip unpopulated entry */
|
|
if (!msr[bit].msr)
|
|
continue;
|
|
|
|
if (msr[bit].test && !msr[bit].test(bit, data))
|
|
continue;
|
|
/* Virt sucks; you cannot tell if a R/O MSR is present :/ */
|
|
if (rdmsrl_safe(msr[bit].msr, &val))
|
|
continue;
|
|
|
|
mask = msr[bit].mask;
|
|
if (!mask)
|
|
mask = ~0ULL;
|
|
/* Disable zero counters if requested. */
|
|
if (!zero && !(val & mask))
|
|
continue;
|
|
|
|
grp->is_visible = NULL;
|
|
}
|
|
avail |= BIT(bit);
|
|
}
|
|
|
|
return avail;
|
|
}
|
|
EXPORT_SYMBOL_GPL(perf_msr_probe);
|