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SubjectRe: [PATCH v3] perf: cs-etm: update ETM metadata format
Hi Leo,

On Sat, 23 Jan 2021 at 15:23, Leo Yan <leo.yan@linaro.org> wrote:
>
> Hi Mike,
>
> On Tue, Jan 19, 2021 at 06:01:10PM +0000, Mike Leach wrote:
>
> [...]
>
> > +/*
> > + * Read a single cpu parameter block from the auxtrace_info priv block.
> > + *
> > + * For version 1 there is a per cpu nr_params entry. If we are handling
> > + * version 1 file, then there may be less, the same, or more params
> > + * indicated by this value than the compile time number we understand.
> > + *
> > + * For a version 0 info block, there are a fixed number, and we need to
> > + * fill out the nr_param value in the metadata we create.
> > + */
> > +static u64 *cs_etm__create_meta_blk(u64 *buff_in, int *buff_in_offset,
> > + int out_blk_size, int nr_params_v0)
> > +{
> > + u64 *metadata = NULL;
> > + int hdr_version;
> > + int nr_in_params, nr_out_params, nr_cmn_params;
> > + int i, k;
> > +
> > + metadata = zalloc(sizeof(*metadata) * out_blk_size);
> > + if (!metadata)
> > + return NULL;
> > +
> > + /* read block current index & version */
> > + i = *buff_in_offset;
> > + hdr_version = buff_in[CS_HEADER_VERSION];
> > +
> > + if (!hdr_version) {
> > + /* read version 0 info block into a version 1 metadata block */
> > + nr_in_params = nr_params_v0;
> > + metadata[CS_ETM_MAGIC] = buff_in[i + CS_ETM_MAGIC];
> > + metadata[CS_ETM_CPU] = buff_in[i + CS_ETM_CPU];
> > + metadata[CS_ETM_NR_TRC_PARAMS] = nr_in_params;
> > + /* remaining block params at offset +1 from source */
> > + for (k = CS_ETM_ETMCR; k < nr_in_params; k++)
> > + metadata[k+1] = buff_in[i + k];
>
> Here it misses to copy data into metadata[CS_ETM_ETMCR], you could see
> it starts to copy from offset 3 (k = CS_ETM_ETMCR) from buff_in,
> actually it's the item for CS_ETM_ETMTRACEIDR in the metadata v0.
>
> So need to change the logic as below; please confirm if I
> misunderstand or not.
>
> for (k = CS_ETM_ETMCR - 1; k < nr_in_params; k++)
> metadata[k+1] = buff_in[i + k];
>

You are correct - this is the correct code for v0 metadata - I will
fix for v4 of the patch.

Thanks

Mike

> Except this issue for ETMv3, I didn't find any other logic issue for
> ETMv4; I tested and confirmed the tool shows the consistent result for
> metadata v0 before and after applying this patch; and it handles
> metadata v1 correctly.
>
> So after fixed the issue for ETMv3, the change looks good to me:
>
> Reviewed-by: Leo Yan <leo.yan@linaro.org>
> Tested-by: Leo Yan <leo.yan@linaro.org>
>
> Thanks!
>
> > + /* version 0 has 2 common params */
> > + nr_cmn_params = 2;
> > + } else {
> > + /* read version 1 info block - input and output nr_params may differ */
> > + /* version 1 has 3 common params */
> > + nr_cmn_params = 3;
> > + nr_in_params = buff_in[i + CS_ETM_NR_TRC_PARAMS];
> > +
> > + /* if input has more params than output - skip excess */
> > + nr_out_params = nr_in_params + nr_cmn_params;
> > + if (nr_out_params > out_blk_size)
> > + nr_out_params = out_blk_size;
> > +
> > + for (k = CS_ETM_MAGIC; k < nr_out_params; k++)
> > + metadata[k] = buff_in[i + k];
> > +
> > + /* record the actual nr params we copied */
> > + metadata[CS_ETM_NR_TRC_PARAMS] = nr_out_params - nr_cmn_params;
> > + }
> > +
> > + /* adjust in offset by number of in params used */
> > + i += nr_in_params + nr_cmn_params;
> > + *buff_in_offset = i;
> > + return metadata;
> > +}
> > +
> > int cs_etm__process_auxtrace_info(union perf_event *event,
> > struct perf_session *session)
> > {
> > @@ -2492,11 +2635,12 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> > int info_header_size;
> > int total_size = auxtrace_info->header.size;
> > int priv_size = 0;
> > - int num_cpu;
> > - int err = 0, idx = -1;
> > - int i, j, k;
> > + int num_cpu, trcidr_idx;
> > + int err = 0;
> > + int i, j;
> > u64 *ptr, *hdr = NULL;
> > u64 **metadata = NULL;
> > + u64 hdr_version;
> >
> > /*
> > * sizeof(auxtrace_info_event::type) +
> > @@ -2512,16 +2656,21 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> > /* First the global part */
> > ptr = (u64 *) auxtrace_info->priv;
> >
> > - /* Look for version '0' of the header */
> > - if (ptr[0] != 0)
> > + /* Look for version of the header */
> > + hdr_version = ptr[0];
> > + if (hdr_version > CS_HEADER_CURRENT_VERSION) {
> > + /* print routine will print an error on bad version */
> > + if (dump_trace)
> > + cs_etm__print_auxtrace_info(auxtrace_info->priv, 0);
> > return -EINVAL;
> > + }
> >
> > - hdr = zalloc(sizeof(*hdr) * CS_HEADER_VERSION_0_MAX);
> > + hdr = zalloc(sizeof(*hdr) * CS_HEADER_VERSION_MAX);
> > if (!hdr)
> > return -ENOMEM;
> >
> > /* Extract header information - see cs-etm.h for format */
> > - for (i = 0; i < CS_HEADER_VERSION_0_MAX; i++)
> > + for (i = 0; i < CS_HEADER_VERSION_MAX; i++)
> > hdr[i] = ptr[i];
> > num_cpu = hdr[CS_PMU_TYPE_CPUS] & 0xffffffff;
> > pmu_type = (unsigned int) ((hdr[CS_PMU_TYPE_CPUS] >> 32) &
> > @@ -2552,35 +2701,31 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> > */
> > for (j = 0; j < num_cpu; j++) {
> > if (ptr[i] == __perf_cs_etmv3_magic) {
> > - metadata[j] = zalloc(sizeof(*metadata[j]) *
> > - CS_ETM_PRIV_MAX);
> > - if (!metadata[j]) {
> > - err = -ENOMEM;
> > - goto err_free_metadata;
> > - }
> > - for (k = 0; k < CS_ETM_PRIV_MAX; k++)
> > - metadata[j][k] = ptr[i + k];
> > + metadata[j] =
> > + cs_etm__create_meta_blk(ptr, &i,
> > + CS_ETM_PRIV_MAX,
> > + CS_ETM_NR_TRC_PARAMS_V0);
> >
> > /* The traceID is our handle */
> > - idx = metadata[j][CS_ETM_ETMTRACEIDR];
> > - i += CS_ETM_PRIV_MAX;
> > + trcidr_idx = CS_ETM_ETMTRACEIDR;
> > +
> > } else if (ptr[i] == __perf_cs_etmv4_magic) {
> > - metadata[j] = zalloc(sizeof(*metadata[j]) *
> > - CS_ETMV4_PRIV_MAX);
> > - if (!metadata[j]) {
> > - err = -ENOMEM;
> > - goto err_free_metadata;
> > - }
> > - for (k = 0; k < CS_ETMV4_PRIV_MAX; k++)
> > - metadata[j][k] = ptr[i + k];
> > + metadata[j] =
> > + cs_etm__create_meta_blk(ptr, &i,
> > + CS_ETMV4_PRIV_MAX,
> > + CS_ETMV4_NR_TRC_PARAMS_V0);
> >
> > /* The traceID is our handle */
> > - idx = metadata[j][CS_ETMV4_TRCTRACEIDR];
> > - i += CS_ETMV4_PRIV_MAX;
> > + trcidr_idx = CS_ETMV4_TRCTRACEIDR;
> > + }
> > +
> > + if (!metadata[j]) {
> > + err = -ENOMEM;
> > + goto err_free_metadata;
> > }
> >
> > /* Get an RB node for this CPU */
> > - inode = intlist__findnew(traceid_list, idx);
> > + inode = intlist__findnew(traceid_list, metadata[j][trcidr_idx]);
> >
> > /* Something went wrong, no need to continue */
> > if (!inode) {
> > @@ -2601,7 +2746,7 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> > }
> >
> > /*
> > - * Each of CS_HEADER_VERSION_0_MAX, CS_ETM_PRIV_MAX and
> > + * Each of CS_HEADER_VERSION_MAX, CS_ETM_PRIV_MAX and
> > * CS_ETMV4_PRIV_MAX mark how many double words are in the
> > * global metadata, and each cpu's metadata respectively.
> > * The following tests if the correct number of double words was
> > @@ -2703,6 +2848,12 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
> > intlist__delete(traceid_list);
> > err_free_hdr:
> > zfree(&hdr);
> > -
> > + /*
> > + * At this point, as a minimum we have valid header. Dump the rest of
> > + * the info section - the print routines will error out on structural
> > + * issues.
> > + */
> > + if (dump_trace)
> > + cs_etm__print_auxtrace_info(auxtrace_info->priv, num_cpu);
> > return err;
> > }
> > diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
> > index 4ad925d6d799..e153d02df0de 100644
> > --- a/tools/perf/util/cs-etm.h
> > +++ b/tools/perf/util/cs-etm.h
> > @@ -17,23 +17,37 @@ struct perf_session;
> > */
> > enum {
> > /* Starting with 0x0 */
> > - CS_HEADER_VERSION_0,
> > + CS_HEADER_VERSION,
> > /* PMU->type (32 bit), total # of CPUs (32 bit) */
> > CS_PMU_TYPE_CPUS,
> > CS_ETM_SNAPSHOT,
> > - CS_HEADER_VERSION_0_MAX,
> > + CS_HEADER_VERSION_MAX,
> > };
> >
> > +/*
> > + * Update the version for new format.
> > + *
> > + * New version 1 format adds a param count to the per cpu metadata.
> > + * This allows easy adding of new metadata parameters.
> > + * Requires that new params always added after current ones.
> > + * Also allows client reader to handle file versions that are different by
> > + * checking the number of params in the file vs the number expected.
> > + */
> > +#define CS_HEADER_CURRENT_VERSION 1
> > +
> > /* Beginning of header common to both ETMv3 and V4 */
> > enum {
> > CS_ETM_MAGIC,
> > CS_ETM_CPU,
> > + /* Number of trace config params in following ETM specific block */
> > + CS_ETM_NR_TRC_PARAMS,
> > + CS_ETM_COMMON_BLK_MAX_V1,
> > };
> >
> > /* ETMv3/PTM metadata */
> > enum {
> > /* Dynamic, configurable parameters */
> > - CS_ETM_ETMCR = CS_ETM_CPU + 1,
> > + CS_ETM_ETMCR = CS_ETM_COMMON_BLK_MAX_V1,
> > CS_ETM_ETMTRACEIDR,
> > /* RO, taken from sysFS */
> > CS_ETM_ETMCCER,
> > @@ -41,10 +55,13 @@ enum {
> > CS_ETM_PRIV_MAX,
> > };
> >
> > +/* define fixed version 0 length - allow new format reader to read old files. */
> > +#define CS_ETM_NR_TRC_PARAMS_V0 (CS_ETM_ETMIDR - CS_ETM_ETMCR + 1)
> > +
> > /* ETMv4 metadata */
> > enum {
> > /* Dynamic, configurable parameters */
> > - CS_ETMV4_TRCCONFIGR = CS_ETM_CPU + 1,
> > + CS_ETMV4_TRCCONFIGR = CS_ETM_COMMON_BLK_MAX_V1,
> > CS_ETMV4_TRCTRACEIDR,
> > /* RO, taken from sysFS */
> > CS_ETMV4_TRCIDR0,
> > @@ -55,6 +72,9 @@ enum {
> > CS_ETMV4_PRIV_MAX,
> > };
> >
> > +/* define fixed version 0 length - allow new format reader to read old files. */
> > +#define CS_ETMV4_NR_TRC_PARAMS_V0 (CS_ETMV4_TRCAUTHSTATUS - CS_ETMV4_TRCCONFIGR + 1)
> > +
> > /*
> > * ETMv3 exception encoding number:
> > * See Embedded Trace Macrocell spcification (ARM IHI 0014Q)
> > @@ -162,7 +182,7 @@ struct cs_etm_packet_queue {
> >
> > #define BMVAL(val, lsb, msb) ((val & GENMASK(msb, lsb)) >> lsb)
> >
> > -#define CS_ETM_HEADER_SIZE (CS_HEADER_VERSION_0_MAX * sizeof(u64))
> > +#define CS_ETM_HEADER_SIZE (CS_HEADER_VERSION_MAX * sizeof(u64))
> >
> > #define __perf_cs_etmv3_magic 0x3030303030303030ULL
> > #define __perf_cs_etmv4_magic 0x4040404040404040ULL
> > --
> > 2.17.1
> >



--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

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