Messages in this thread Patch in this message | | | From | Jiri Olsa <> | Subject | [PATCH 1/8] perf/x86: Add msr probe interface | Date | Mon, 27 May 2019 23:51:22 +0200 |
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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, void *data)
Together with: cnt - which is the number of struct msr array elements 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 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> --- arch/x86/events/Makefile | 2 +- arch/x86/events/probe.c | 42 ++++++++++++++++++++++++++++++++++++++++ arch/x86/events/probe.h | 29 +++++++++++++++++++++++++++ 3 files changed, 72 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..0b190f779ee1 --- /dev/null +++ b/arch/x86/events/probe.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/export.h> +#include <linux/types.h> +#include <linux/bits.h> +#include "probe.h" + +static umode_t +not_visible(struct kobject *kobj, struct attribute *attr, int i) +{ + return 0; +} + +unsigned long +perf_msr_probe(struct perf_msr *msr, int cnt, void *data) +{ + unsigned long avail = 0; + unsigned int bit; + u64 val; + + if (cnt >= BITS_PER_LONG) + return 0; + + for (bit = 0; bit < cnt; bit++) { + if (!msr[bit].no_check) { + struct attribute_group *grp = msr[bit].grp; + + grp->is_visible = not_visible; + + if (msr[bit].test && !msr[bit].test(bit, data)) + continue; + /* Virt sucks; you cannot tell if a R/O MSR is present :/ */ + if (rdmsrl_safe(msr[bit].msr, &val) || !val) + continue; + + grp->is_visible = NULL; + } + avail |= BIT(bit); + } + + 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..f2c34c25f8a5 --- /dev/null +++ b/arch/x86/events/probe.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ARCH_X86_EVENTS_PROBE_H__ +#define __ARCH_X86_EVENTS_PROBE_H__ +#include <linux/sysfs.h> + +struct perf_msr { + u64 msr; + struct attribute_group *grp; + bool (*test)(int idx, void *data); + bool no_check; +}; + +unsigned long +perf_msr_probe(struct perf_msr *msr, int cnt, void *data); + +#define __PMU_EVENT_GROUP(_name) \ +static struct attribute *attrs_##_name[] = { \ + &attr_##_name.attr.attr, \ + NULL, \ +} + +#define PMU_EVENT_GROUP(_grp, _name) \ +__PMU_EVENT_GROUP(_name); \ +static struct attribute_group group_##_name = { \ + .name = #_grp, \ + .attrs = attrs_##_name, \ +} + +#endif /* __ARCH_X86_EVENTS_PROBE_H__ */ -- 2.20.1
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