arch/x86/events/probe.c

   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 unsigned long
  14 perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
  15 {
  16         unsigned long avail = 0;
  17         unsigned int bit;
  18         u64 val;
  19
  20         if (cnt >= BITS_PER_LONG)
  21                 return 0;
  22
  23         for (bit = 0; bit < cnt; bit++) {
  24                 if (!msr[bit].no_check) {
  25                         struct attribute_group *grp = msr[bit].grp;
  26
  27                         grp->is_visible = not_visible;
  28
  29                         if (msr[bit].test && !msr[bit].test(bit, data))
  30                                 continue;
  31                         /* Virt sucks; you cannot tell if a R/O MSR is present :/ */
  32                         if (rdmsrl_safe(msr[bit].msr, &val))
  33                                 continue;
  34                         /* Disable zero counters if requested. */
  35                         if (!zero && !val)
  36                                 continue;
  37
  38                         grp->is_visible = NULL;
  39                 }
  40                 avail |= BIT(bit);
  41         }
  42
  43         return avail;
  44 }
  45 EXPORT_SYMBOL_GPL(perf_msr_probe);