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Message-ID: <20141021091434.GN23531@worktop.programming.kicks-ass.net>
Date: Tue, 21 Oct 2014 11:14:34 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Hendrik Brueckner <brueckner@...ux.vnet.ibm.com>,
Andy Lutomirski <luto@...capital.net>,
Valdis Kletnieks <Valdis.Kletnieks@...edu>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Paul Mackerras <paulus@...ba.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Ingo Molnar <mingo@...hat.com>,
Kees Cook <keescook@...omium.org>,
Andrea Arcangeli <aarcange@...hat.com>,
Erik Bosman <ebn310@....vu.nl>, mpe@...erman.id.au,
anton@...ba.org, schwidefsky@...ibm.com
Subject: Re: [RFC 5/5] x86,perf: Only allow rdpmc if a perf_event is mapped
On Mon, Oct 20, 2014 at 12:51:10PM +0200, Hendrik Brueckner wrote:
> I think it would makes sense to return 0 as default in the
> perf_event_idx_default() and let each PMU/arch that actually supports
> reading PMCs from user space return the proper index. And according
> to tools/perf/design.txt, index must be non-zero to trigger a user space
> read.
OK, I've got something like the below. Michael/Anton, would you please
clarify the ppc book3s capabilities?
---
Subject: perf: Clean up pmu::event_idx
From: Peter Zijlstra <peterz@...radead.org>
Date: Tue Oct 21 11:10:21 CEST 2014
Andy reported that the current state of event_idx is rather confused.
So remove all but the x86_pmu implementation and change the default to
return 0 (the safe option).
Reported-by: Andy Lutomirski <luto@...capital.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
arch/powerpc/perf/hv-24x7.c | 6 ------
arch/powerpc/perf/hv-gpci.c | 6 ------
arch/s390/kernel/perf_cpum_sf.c | 6 ------
kernel/events/core.c | 15 +--------------
kernel/events/hw_breakpoint.c | 7 -------
5 files changed, 1 insertion(+), 39 deletions(-)
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -417,11 +417,6 @@ static int h_24x7_event_add(struct perf_
return 0;
}
-static int h_24x7_event_idx(struct perf_event *event)
-{
- return 0;
-}
-
static struct pmu h_24x7_pmu = {
.task_ctx_nr = perf_invalid_context,
@@ -433,7 +428,6 @@ static struct pmu h_24x7_pmu = {
.start = h_24x7_event_start,
.stop = h_24x7_event_stop,
.read = h_24x7_event_update,
- .event_idx = h_24x7_event_idx,
};
static int hv_24x7_init(void)
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -246,11 +246,6 @@ static int h_gpci_event_init(struct perf
return 0;
}
-static int h_gpci_event_idx(struct perf_event *event)
-{
- return 0;
-}
-
static struct pmu h_gpci_pmu = {
.task_ctx_nr = perf_invalid_context,
@@ -262,7 +257,6 @@ static struct pmu h_gpci_pmu = {
.start = h_gpci_event_start,
.stop = h_gpci_event_stop,
.read = h_gpci_event_update,
- .event_idx = h_gpci_event_idx,
};
static int hv_gpci_init(void)
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1411,11 +1411,6 @@ static void cpumsf_pmu_del(struct perf_e
perf_pmu_enable(event->pmu);
}
-static int cpumsf_pmu_event_idx(struct perf_event *event)
-{
- return event->hw.idx;
-}
-
CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF);
CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG);
@@ -1458,7 +1453,6 @@ static struct pmu cpumf_sampling = {
.stop = cpumsf_pmu_stop,
.read = cpumsf_pmu_read,
- .event_idx = cpumsf_pmu_event_idx,
.attr_groups = cpumsf_pmu_attr_groups,
};
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6071,11 +6071,6 @@ static int perf_swevent_init(struct perf
return 0;
}
-static int perf_swevent_event_idx(struct perf_event *event)
-{
- return 0;
-}
-
static struct pmu perf_swevent = {
.task_ctx_nr = perf_sw_context,
@@ -6085,8 +6080,6 @@ static struct pmu perf_swevent = {
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
-
- .event_idx = perf_swevent_event_idx,
};
#ifdef CONFIG_EVENT_TRACING
@@ -6204,8 +6197,6 @@ static struct pmu perf_tracepoint = {
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
-
- .event_idx = perf_swevent_event_idx,
};
static inline void perf_tp_register(void)
@@ -6431,8 +6422,6 @@ static struct pmu perf_cpu_clock = {
.start = cpu_clock_event_start,
.stop = cpu_clock_event_stop,
.read = cpu_clock_event_read,
-
- .event_idx = perf_swevent_event_idx,
};
/*
@@ -6511,8 +6500,6 @@ static struct pmu perf_task_clock = {
.start = task_clock_event_start,
.stop = task_clock_event_stop,
.read = task_clock_event_read,
-
- .event_idx = perf_swevent_event_idx,
};
static void perf_pmu_nop_void(struct pmu *pmu)
@@ -6542,7 +6529,7 @@ static void perf_pmu_cancel_txn(struct p
static int perf_event_idx_default(struct perf_event *event)
{
- return event->hw.idx + 1;
+ return 0;
}
/*
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -605,11 +605,6 @@ static void hw_breakpoint_stop(struct pe
bp->hw.state = PERF_HES_STOPPED;
}
-static int hw_breakpoint_event_idx(struct perf_event *bp)
-{
- return 0;
-}
-
static struct pmu perf_breakpoint = {
.task_ctx_nr = perf_sw_context, /* could eventually get its own */
@@ -619,8 +614,6 @@ static struct pmu perf_breakpoint = {
.start = hw_breakpoint_start,
.stop = hw_breakpoint_stop,
.read = hw_breakpoint_pmu_read,
-
- .event_idx = hw_breakpoint_event_idx,
};
int __init init_hw_breakpoint(void)
--
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