On Thu, Feb 04, 2021 at 10:54:24AM +0000, Suzuki Kuruppassery Poulose wrote:
[...]
+int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt) +{
- struct int_node *inode;
- u64 *metadata, val;
- inode = intlist__find(traceid_list, trace_chan_id);
- if (!inode)
return -EINVAL;- metadata = inode->priv;
- if (metadata[CS_ETM_MAGIC] == __perf_cs_etmv3_magic) {
val = metadata[CS_ETM_ETMCR];/* CONTEXTIDR is traced */if (val & BIT(ETM_OPT_CTXTID))*pid_fmt = BIT(ETM_OPT_CTXTID);- } else {
val = metadata[CS_ETMV4_TRCCONFIGR];*pid_fmt = 0;/* CONTEXTIDR_EL2 is traced */if (val & (BIT(ETM4_CFG_BIT_VMID) | BIT(ETM4_CFG_BIT_VMID_OPT)))*pid_fmt = BIT(ETM_OPT_CTXTID2);/* CONTEXTIDR_EL1 is traced */if (val & BIT(ETM4_CFG_BIT_CTXTID))I haven't looked at how this gets used. But, Shouldn't this be :
else if (val & BIT(ETM4_CFG_BIT_CTXTID)) ?Actually it's deliberately to set both bits ETM_OPT_CTXTID2 and ETM_OPT_CTXTID if user has enable configs "contextid1" and "contextid2". So this is exactly the reversed flow in the function cs_etmv4_get_config().
The point is, we don't care if the user selected both options. What we care is, where can we find the PID. CONTEXTIDR_EL1 or CONTEXTIDR_EL2. As such, get_pid_fmt simply should make that decision and pass it on. So, if the CONTEXTIDR_EL2 is selected (which can only be done successfully on an EL2 kernel), thats our pid.
So we should return the format for the PID here. i.e ETM_OPT_CTXTID2 OR ETM_OPT_CTXTID. But not both.
Okay, if so I will follow your suggestion.
Thanks, Leo