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98253a546a
Adding perf_msr_probe function to provide interface for
checking up on MSR register and set the related attribute
group visibility.
User defines following struct for each MSR register:
struct perf_msr {
u64 msr;
struct attribute_group *grp;
bool (*test)(int idx, void *data);
bool no_check;
};
Where:
msr - is the MSR address
attrs - is attribute groups array to add if the check passed
test - is test function pointer
no_check - is bool that bypass the check and adds the
attribute without any test
The array of struct perf_msr is passed into:
perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
Together with:
cnt - which is the number of struct msr array elements
data - which is user pointer passed to the test function
zero - allow counters that returns zero on rdmsr
The perf_msr_probe will executed test code, read the MSR and
check the value is != 0. If all these tests pass, related
attribute group is kept visible.
Also adding PMU_EVENT_GROUP macro helper to define attribute
group for single attribute. It will be used in following patches.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-2-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
46 lines
927 B
C
46 lines
927 B
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/export.h>
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#include <linux/types.h>
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#include <linux/bits.h>
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#include "probe.h"
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static umode_t
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not_visible(struct kobject *kobj, struct attribute *attr, int i)
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{
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return 0;
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}
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unsigned long
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perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
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{
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unsigned long avail = 0;
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unsigned int bit;
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u64 val;
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if (cnt >= BITS_PER_LONG)
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return 0;
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for (bit = 0; bit < cnt; bit++) {
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if (!msr[bit].no_check) {
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struct attribute_group *grp = msr[bit].grp;
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grp->is_visible = not_visible;
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if (msr[bit].test && !msr[bit].test(bit, data))
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continue;
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/* Virt sucks; you cannot tell if a R/O MSR is present :/ */
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if (rdmsrl_safe(msr[bit].msr, &val))
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continue;
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/* Disable zero counters if requested. */
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if (!zero && !val)
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continue;
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grp->is_visible = NULL;
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}
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avail |= BIT(bit);
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}
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return avail;
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}
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EXPORT_SYMBOL_GPL(perf_msr_probe);
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