lkml.org 
[lkml]   [2022]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[RFC V1 11/11] perf: Capture branch privilege information
    Date
    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/drivers/perf/arm_pmu_brbe.c b/drivers/perf/arm_pmu_brbe.c
    index 7cd1208c6c58..d4cbea74c148 100644
    --- a/drivers/perf/arm_pmu_brbe.c
    +++ b/drivers/perf/arm_pmu_brbe.c
    @@ -270,6 +270,25 @@ static int brbe_fetch_perf_type(u64 brbinf)
    }
    }

    +static int brbe_fetch_perf_priv(u64 brbinf)
    +{
    + int brbe_el = brbe_fetch_el(brbinf);
    +
    + switch (brbe_el) {
    + case BRBINF_EL_EL0:
    + return PERF_BR_USER;
    + case BRBINF_EL_EL1:
    + return PERF_BR_KERNEL;
    + case BRBINF_EL_EL2:
    + if (is_kernel_in_hyp_mode())
    + return PERF_BR_KERNEL;
    + return PERF_BR_HV;
    + default:
    + pr_warn("unknown branch privilege captured\n");
    + return -1;
    + }
    +}
    +
    static void capture_brbe_flags(struct pmu_hw_events *cpuc, struct perf_event *event,
    u64 brbinf, int idx)
    {
    @@ -302,6 +321,15 @@ static void capture_brbe_flags(struct pmu_hw_events *cpuc, struct perf_event *ev
    cpuc->brbe_entries[idx].in_tx = brbinf & BRBINF_TX;
    }
    }
    +
    + if (branch_sample_priv(event)) {
    + /*
    + * All these information (i.e branch privilege level) are not
    + * available for source only branch records.
    + */
    + if (type != BRBINF_VALID_SOURCE)
    + cpuc->brbe_entries[idx].priv = brbe_fetch_perf_priv(brbinf);
    + }
    }

    /*
    diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
    index 916ce5102b33..8021b6a30d86 100644
    --- a/include/linux/perf_event.h
    +++ b/include/linux/perf_event.h
    @@ -1688,4 +1688,9 @@ static inline bool branch_sample_hw_index(const struct perf_event *event)
    {
    return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
    }
    +
    +static inline bool branch_sample_priv(const struct perf_event *event)
    +{
    + return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_PRIV_SAVE;
    +}
    #endif /* _LINUX_PERF_EVENT_H */
    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 */
    +
    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/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
    };

    --
    2.25.1
    \
     
     \ /
      Last update: 2022-01-24 05:40    [W:4.381 / U:0.228 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site