Messages in this thread Patch in this message | | | From | Jiri Olsa <> | Subject | [PATCH 1/8] perf/x86: Add msr probe interface | Date | Mon, 18 Mar 2019 19:21:09 +0100 |
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Adding perf_msr_probe function to provide interface for checking up on MSR register and add its related event attributes if it passes the check.
User defines following struct for each MSR register:
struct perf_msr { u64 msr; struct attribute **attrs; bool (*test)(int idx, void *data); bool no_check; };
Where: msr - is the MSR address attrs - is attributes 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, struct attribute **attrs, void *data)
Together with: cnt - which is the number of struct msr array elements attrs - which is an array placeholder for added attributes and needs to be big enough data -which is user pointer passed to the test function
The perf_msr_probe will executed test code, read the MSR and check the value is != 0. If all these tests pass, related attributes are added into attrs array.
Also adding MSR_ATTR macro helper to define attribute array from single attribute. It will be used in following patches.
Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- arch/x86/events/Makefile | 2 +- arch/x86/events/probe.c | 36 ++++++++++++++++++++++++++++++++++++ arch/x86/events/probe.h | 22 ++++++++++++++++++++++ 3 files changed, 59 insertions(+), 1 deletion(-) create mode 100644 arch/x86/events/probe.c create mode 100644 arch/x86/events/probe.h
diff --git a/arch/x86/events/Makefile b/arch/x86/events/Makefile index b8ccdb5c9244..ec29a466444a 100644 --- a/arch/x86/events/Makefile +++ b/arch/x86/events/Makefile @@ -1,4 +1,4 @@ -obj-y += core.o +obj-y += core.o probe.o obj-y += amd/ obj-$(CONFIG_X86_LOCAL_APIC) += msr.o obj-$(CONFIG_CPU_SUP_INTEL) += intel/ diff --git a/arch/x86/events/probe.c b/arch/x86/events/probe.c new file mode 100644 index 000000000000..0052b730c55e --- /dev/null +++ b/arch/x86/events/probe.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/export.h> +#include <linux/bits.h> +#include "probe.h" + +unsigned long +perf_msr_probe(struct perf_msr *msr, int cnt, + struct attribute **attrs, void *data) +{ + unsigned long avail = 0; + unsigned int bit; + u64 val; + + if (cnt >= BITS_PER_LONG) + return 0; + + for (bit = 0; bit < cnt; bit++) { + struct attribute **a = msr[bit].attrs; + + if (!msr[bit].no_check) { + if (msr[bit].test && !msr[bit].test(bit, data)) + continue; + if (rdmsrl_safe(msr[bit].msr, &val) || !val) + continue; + } + + while (*a) + *attrs++ = *a++; + + avail |= bit; + } + + *attrs = NULL; + return avail; +} +EXPORT_SYMBOL_GPL(perf_msr_probe); diff --git a/arch/x86/events/probe.h b/arch/x86/events/probe.h new file mode 100644 index 000000000000..42dd666533c3 --- /dev/null +++ b/arch/x86/events/probe.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ARCH_X86_EVENTS_PROBE_H__ +#define __ARCH_X86_EVENTS_PROBE_H__ +#include <linux/sysfs.h> + +#define MSR_ATTR(__n) \ +static struct attribute *msr_##__n[] = { \ + &__n.attr.attr, \ + NULL, \ +} + +struct perf_msr { + u64 msr; + struct attribute **attrs; + bool (*test)(int idx, void *data); + bool no_check; +}; + +unsigned long +perf_msr_probe(struct perf_msr *msr, int cnt, + struct attribute **attrs, void *data); +#endif /* __ARCH_X86_EVENTS_PROBE_H__ */ -- 2.17.2
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