Messages in this thread Patch in this message | | | Subject | Re: [RFC V1 11/11] perf: Capture branch privilege information | From | James Clark <> | Date | Tue, 25 Jan 2022 15:39:24 +0000 |
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On 24/01/2022 04:30, Anshuman Khandual wrote: > Platforms like arm64 could capture privilege level information for all the > branch records. Hence this adds a new element in the struct branch_entry to > record the privilege level information, which could be requested through a > new event.attr.branch_sample_type flag PERF_SAMPLE_BRANCH_PRIV_SAVE. While > here, update the BRBE driver as required. > > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Arnaldo Carvalho de Melo <acme@kernel.org> > Cc: Jiri Olsa <jolsa@redhat.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-perf-users@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > drivers/perf/arm_pmu_brbe.c | 28 ++++++++++++++++++++++++ > include/linux/perf_event.h | 5 +++++ > include/uapi/linux/perf_event.h | 13 ++++++++++- > tools/include/uapi/linux/perf_event.h | 13 ++++++++++- > tools/perf/Documentation/perf-record.txt | 1 + > tools/perf/util/parse-branch-options.c | 1 + > 6 files changed, 59 insertions(+), 2 deletions(-) > [...] > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h > index 361fdc6b87a0..4d77710f7a4e 100644 > --- a/include/uapi/linux/perf_event.h > +++ b/include/uapi/linux/perf_event.h > @@ -204,6 +204,8 @@ enum perf_branch_sample_type_shift { > > PERF_SAMPLE_BRANCH_HW_INDEX_SHIFT = 17, /* save low level index of raw branch records */ > > + PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT = 18, /* save privillege mode */
privillege -> privilege
> + > PERF_SAMPLE_BRANCH_MAX_SHIFT /* non-ABI */ > }; > > @@ -233,6 +235,8 @@ enum perf_branch_sample_type { > > PERF_SAMPLE_BRANCH_HW_INDEX = 1U << PERF_SAMPLE_BRANCH_HW_INDEX_SHIFT, > > + PERF_SAMPLE_BRANCH_PRIV_SAVE = 1U << PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT, > +
Can you also add the new entry to the perf verbose printer otherwise it looks like it's not being set on branch_sample_type (as in when using ./perf record -j any_call,u,priv -vvv):
static void __p_branch_sample_type(char *buf, size_t size, u64 value) { #define bit_name(n) { PERF_SAMPLE_BRANCH_##n, #n } struct bit_names bits[] = { bit_name(USER), bit_name(KERNEL), bit_name(HV), bit_name(ANY), bit_name(ANY_CALL), bit_name(ANY_RETURN), bit_name(IND_CALL), bit_name(ABORT_TX), bit_name(IN_TX), bit_name(NO_TX), bit_name(COND), bit_name(CALL_STACK), bit_name(IND_JUMP), bit_name(CALL), bit_name(NO_FLAGS), bit_name(NO_CYCLES), bit_name(HW_INDEX), { .name = NULL, } }; #undef bit_name __p_bits(buf, size, value, bits); }
PERF_SAMPLE_BRANCH_TYPE_SAVE_SHIFT is also missing so it probably makes sense to add it at the same time as that was expanded for BRBE.
> PERF_SAMPLE_BRANCH_MAX = 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT, > }; > > @@ -265,6 +269,12 @@ enum { > PERF_BR_MAX, > }; > > +enum { > + PERF_BR_USER = 0, > + PERF_BR_KERNEL = 1, > + PERF_BR_HV = 2, > +}; > + > #define PERF_SAMPLE_BRANCH_PLM_ALL \ > (PERF_SAMPLE_BRANCH_USER|\ > PERF_SAMPLE_BRANCH_KERNEL|\ > @@ -1377,7 +1387,8 @@ struct perf_branch_entry { > abort:1, /* transaction abort */ > cycles:16, /* cycle count to last branch */ > type:6, /* branch type */ > - reserved:38; > + priv:2, /* privilege level */ > + reserved:36; > }; > > union perf_sample_weight { > diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h > index 9a82b8aaed93..a2208400b0b9 100644 > --- a/tools/include/uapi/linux/perf_event.h > +++ b/tools/include/uapi/linux/perf_event.h > @@ -204,6 +204,8 @@ enum perf_branch_sample_type_shift { > > PERF_SAMPLE_BRANCH_HW_INDEX_SHIFT = 17, /* save low level index of raw branch records */ > > + PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT = 18, /* save privillege mode */ > + > PERF_SAMPLE_BRANCH_MAX_SHIFT /* non-ABI */ > }; > > @@ -233,6 +235,8 @@ enum perf_branch_sample_type { > > PERF_SAMPLE_BRANCH_HW_INDEX = 1U << PERF_SAMPLE_BRANCH_HW_INDEX_SHIFT, > > + PERF_SAMPLE_BRANCH_PRIV_SAVE = 1U << PERF_SAMPLE_BRANCH_PRIV_SAVE_SHIFT, > + > PERF_SAMPLE_BRANCH_MAX = 1U << PERF_SAMPLE_BRANCH_MAX_SHIFT, > }; > > @@ -265,6 +269,12 @@ enum { > PERF_BR_MAX, > }; > > +enum { > + PERF_BR_USER = 0, > + PERF_BR_KERNEL = 1, > + PERF_BR_HV = 2, > +}; > + > #define PERF_SAMPLE_BRANCH_PLM_ALL \ > (PERF_SAMPLE_BRANCH_USER|\ > PERF_SAMPLE_BRANCH_KERNEL|\ > @@ -1377,7 +1387,8 @@ struct perf_branch_entry { > abort:1, /* transaction abort */ > cycles:16, /* cycle count to last branch */ > type:6, /* branch type */ > - reserved:38; > + priv:2, /* privilege level */ > + reserved:36; > }; > > union perf_sample_weight { > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt > index 9ccc75935bc5..3e33686977a1 100644 > --- a/tools/perf/Documentation/perf-record.txt > +++ b/tools/perf/Documentation/perf-record.txt > @@ -387,6 +387,7 @@ following filters are defined: > - abort_tx: only when the target is a hardware transaction abort > - cond: conditional branches > - save_type: save branch type during sampling in case binary is not available later > + - priv: save privilege state during sampling in case binary is not available later > > + > The option requires at least one branch type among any, any_call, any_ret, ind_call, cond. > diff --git a/tools/perf/util/parse-branch-options.c b/tools/perf/util/parse-branch-options.c > index bb4aa88c50a8..00588b9db474 100644 > --- a/tools/perf/util/parse-branch-options.c > +++ b/tools/perf/util/parse-branch-options.c > @@ -32,6 +32,7 @@ static const struct branch_mode branch_modes[] = { > BRANCH_OPT("call", PERF_SAMPLE_BRANCH_CALL), > BRANCH_OPT("save_type", PERF_SAMPLE_BRANCH_TYPE_SAVE), > BRANCH_OPT("stack", PERF_SAMPLE_BRANCH_CALL_STACK), > + BRANCH_OPT("priv", PERF_SAMPLE_BRANCH_PRIV_SAVE), > BRANCH_END > }; > >
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