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
7 static umode_t
not_visible(struct kobject * kobj,struct attribute * attr,int i)8 not_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 */
18 unsigned long
perf_msr_probe(struct perf_msr * msr,int cnt,bool zero,void * data)19 perf_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
32 /* skip entry with no group */
33 if (!grp)
34 continue;
35
36 grp->is_visible = not_visible;
37
38 /* skip unpopulated entry */
39 if (!msr[bit].msr)
40 continue;
41
42 if (msr[bit].test && !msr[bit].test(bit, data))
43 continue;
44 /* Virt sucks; you cannot tell if a R/O MSR is present :/ */
45 if (rdmsrl_safe(msr[bit].msr, &val))
46 continue;
47 /* Disable zero counters if requested. */
48 if (!zero && !val)
49 continue;
50
51 grp->is_visible = NULL;
52 }
53 avail |= BIT(bit);
54 }
55
56 return avail;
57 }
58 EXPORT_SYMBOL_GPL(perf_msr_probe);
59