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SubjectRe: [PATCH v2 12/14] perf arm-spe: Add more sub classes for operation packet
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On 29/09/2020 14:39, Leo Yan wrote:

Hi,

> For the operation type packet payload with load/store class, it misses
> to support these sub classes:
>
> - A load/store targeting the general-purpose registers;
> - A load/store targeting unspecified registers;
> - The ARMv8.4 nested virtualisation extension can redirect system
> register accesses to a memory page controlled by the hypervisor.
> The SPE profiling feature in newer implementations can tag those
> memory accesses accordingly.
>
> Add the bit pattern describing load/store sub classes, so that the perf
> tool can decode it properly.
>
> Inspired by Andre Przywara, refined the commit log and code for more
> clear description.
>
> Co-developed-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
> .../util/arm-spe-decoder/arm-spe-pkt-decoder.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> index a848c784f4cf..57a2d5494838 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> @@ -378,6 +378,21 @@ int arm_spe_pkt_desc(const struct arm_spe_pkt *packet, char *buf,
> ret = arm_spe_pkt_snprintf(&buf, &blen, " SIMD-FP");
> if (ret < 0)
> return ret;
> + } else if ((payload & SPE_OP_PKT_LDST_SUBCLASS_MASK) ==

These three and the one above use the same mask, should this go into a
switch case? Move this block to the end, then do:
switch (payload & SPE_OP_PKT_LDST_SUBCLASS_MASK) {
case SPE_OP_PKT_LDST_SUBCLASS_GP_REG:
...
case SPE_OP_PKT_LDST_SUBCLASS_UNSPEC_REG:
...
Maybe even assign just a string pointer inside, then have one snprintf.
Haven't checked it that *really* looks better, though.

Also those later checks are quite indented, shall those be moved to
helper functions? Again just an idea ....

Cheers,
Andre


> + SPE_OP_PKT_LDST_SUBCLASS_GP_REG) {
> + ret = arm_spe_pkt_snprintf(&buf, &blen, " GP-REG");
> + if (ret < 0)
> + return ret;
> + } else if ((payload & SPE_OP_PKT_LDST_SUBCLASS_MASK) ==
> + SPE_OP_PKT_LDST_SUBCLASS_UNSPEC_REG) {
> + ret = arm_spe_pkt_snprintf(&buf, &blen, " UNSPEC-REG");
> + if (ret < 0)
> + return ret;
> + } else if ((payload & SPE_OP_PKT_LDST_SUBCLASS_MASK) ==
> + SPE_OP_PKT_LDST_SUBCLASS_NV_SYSREG) {
> + ret = arm_spe_pkt_snprintf(&buf, &blen, " NV-SYSREG");
> + if (ret < 0)
> + return ret;
> }
>
> return buf_len - blen;
>

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