| 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 | 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: msr[bit].msr, p: &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 | } |
| 63 | EXPORT_SYMBOL_GPL(perf_msr_probe); |
| 64 |