1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3#include <linux/types.h>
4#include <linux/bits.h>
5#include "probe.h"
6
7static umode_t
8not_visible(struct kobject *kobj, struct attribute *attr, int i)
9{
10	return 0;
11}
12
13/*
14 * Accepts msr[] array with non populated entries as long as either
15 * msr[i].msr is 0 or msr[i].grp is NULL. Note that the default sysfs
16 * visibility is visible when group->is_visible callback is set.
17 */
18unsigned long
19perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
20{
21	unsigned long avail = 0;
22	unsigned int bit;
23	u64 val;
24
25	if (cnt >= BITS_PER_LONG)
26		return 0;
27
28	for (bit = 0; bit < cnt; bit++) {
29		if (!msr[bit].no_check) {
30			struct attribute_group *grp = msr[bit].grp;
31			u64 mask;
32
33			/* skip entry with no group */
34			if (!grp)
35				continue;
36
37			grp->is_visible = not_visible;
38
39			/* skip unpopulated entry */
40			if (!msr[bit].msr)
41				continue;
42
43			if (msr[bit].test && !msr[bit].test(bit, data))
44				continue;
45			/* Virt sucks; you cannot tell if a R/O MSR is present :/ */
46			if (rdmsrl_safe(msr[bit].msr, &val))
47				continue;
48
49			mask = msr[bit].mask;
50			if (!mask)
51				mask = ~0ULL;
52			/* Disable zero counters if requested. */
53			if (!zero && !(val & mask))
54				continue;
55
56			grp->is_visible = NULL;
57		}
58		avail |= BIT(bit);
59	}
60
61	return avail;
62}
63EXPORT_SYMBOL_GPL(perf_msr_probe);
64