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 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 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