1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3#include <linux/types.h>
4#include <linux/bits.h>
5
6#include <asm/msr.h>
7#include "probe.h"
8
9static umode_t
10not_visible(struct kobject *kobj, struct attribute *attr, int i)
11{
12 return 0;
13}
14
15/*
16 * Accepts msr[] array with non populated entries as long as either
17 * msr[i].msr is 0 or msr[i].grp is NULL. Note that the default sysfs
18 * visibility is visible when group->is_visible callback is set.
19 */
20unsigned long
21perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
22{
23 unsigned long avail = 0;
24 unsigned int bit;
25 u64 val;
26
27 if (cnt >= BITS_PER_LONG)
28 return 0;
29
30 for (bit = 0; bit < cnt; bit++) {
31 if (!msr[bit].no_check) {
32 struct attribute_group *grp = msr[bit].grp;
33 u64 mask;
34
35 /* skip entry with no group */
36 if (!grp)
37 continue;
38
39 grp->is_visible = not_visible;
40
41 /* skip unpopulated entry */
42 if (!msr[bit].msr)
43 continue;
44
45 if (msr[bit].test && !msr[bit].test(bit, data))
46 continue;
47 /* Virt sucks; you cannot tell if a R/O MSR is present :/ */
48 if (rdmsrq_safe(msr: msr[bit].msr, p: &val))
49 continue;
50
51 mask = msr[bit].mask;
52 if (!mask)
53 mask = ~0ULL;
54 /* Disable zero counters if requested. */
55 if (!zero && !(val & mask))
56 continue;
57
58 grp->is_visible = NULL;
59 }
60 avail |= BIT(bit);
61 }
62
63 return avail;
64}
65EXPORT_SYMBOL_GPL(perf_msr_probe);
66