Hi Mathieu,
On Tue, 3 Sep 2019 at 20:38, Mathieu Poirier mathieu.poirier@linaro.org wrote:
Hi Mike,
On Thu, Aug 29, 2019 at 10:33:21PM +0100, Mike Leach wrote:
Add in detailed programmers reference for users wanting to program the CoreSight ETM 4.x driver using sysfs.
Signed-off-by: Mike Leach mike.leach@linaro.org
.../coresight/coresight-etm4x-reference.txt | 458 ++++++++++++++++++ 1 file changed, 458 insertions(+) create mode 100644 Documentation/trace/coresight/coresight-etm4x-reference.txt
diff --git a/Documentation/trace/coresight/coresight-etm4x-reference.txt b/Documentation/trace/coresight/coresight-etm4x-reference.txt new file mode 100644 index 000000000000..f0c370870992 --- /dev/null +++ b/Documentation/trace/coresight/coresight-etm4x-reference.txt @@ -0,0 +1,458 @@ +ETMv4 sysfs linux driver programming reference - v2. +====================================================
+Supplement to existing ETMv4 driver documentation.
+Sysfs files and directories +---------------------------
+Root: /sys/bus/coresight/devices/etm<N>
+The following paragraphs explain the association between sysfs files and the +ETMv4 registers that they effect. Note the register names are given without +the ‘TRC’ prefix.
+File : mode (rw) +Trace Registers : {CONFIGR + others} +Notes : Bit select trace features. See ‘mode’ section below. Bits
in this will cause equivalent programming of trace config andother registers to enable the features requested.+Syntax & eg : 'echo bitfield > mode'
bitfield up to 32 bits setting trace features.+Example : $> echo 0x > mode
I suspect things look different on your end than they do on mine. The biggest problem is related to multi-line fields. For instance the above looks like this on my side:
File : mode (rw) Trace Registers : {CONFIGR + others} Notes : Bit select trace features. See ‘mode’ section below. Bits in this will cause equivalent programming of trace config and other registers to enable the features requested. Syntax & eg : 'echo bitfield > mode' bitfield up to 32 bits setting trace features. Example : $> echo 0x > mode
It would be nicer to have multi-line fields aligned with the first line, such as:
File : mode (rw) Trace Registers : {CONFIGR + others} Notes : Bit select trace features. See ‘mode’ section below. Bits in this will cause equivalent programming of trace config and other registers to enable the features requested. Syntax & eg : 'echo bitfield > mode' bitfield up to 32 bits setting trace features. Example : $> echo 0x > mode
Problem is I am not seeing any difference between what you say I am writing and what you prefer. When i looked at the file in my text editor the fields where aligned - I would not have submitted it otherwise. I am happy to revisit it but we need a way of seeing a common view.
I'm also not sure about the prompt, i.e "$>". I suspect it should be "$" and an additional ">" got inserted.
prompt came from examples lifted from a DB410 session. Don't really have any strong preference for what represents a prompt in the docs, so happy to change it to anything appropriate.
Regards
Mike
I wanted to read on but is it too difficult to know what is intentional and what isn't. Please address and resend.
Thanks, Mathieu
+File : reset (wo) +Trace Registers : All +Notes : Reset all programming to trace nothing / no logic programmed. +Syntax : 'echo 1 > reset'
+File : enable_source (wo) +Trace Registers : PRGCTLR, All hardware regs. +Notes : >0: Programs up the hardware with the current values held in
the driver and enables trace.0: disable trace hardware.+Syntax : 'echo 1 > enable_source'
+File : cpu (ro) +Trace Registers : None. +Notes : CPU ID that this ETM is attached to. +Example :$> cat cpu
$> 0+File : addr_idx (rw) +Trace Registers : None. +Notes : Virtual register to index address comparator and range
features. Set index for first of the pair in a range.+Syntax : 'echo idx > addr_idx'
Where idx < nr_addr_cmp x 2+File : addr_range (rw) +Trace Registers : ACVR[idx, idx+1], VIIECTLR +Notes : Pair of addresses for a range selected by addr_idx. Include
/ exclude according to the optional parameter, or if omitteduses the current ‘mode’ setting. Select comparator range incontrol register. Error if index is odd value.+Depends : mode, addr_idx +Syntax : 'echo addr1 addr2 [exclude] > addr_range'
Where addr1 and addr2 define the range and addr1 < addr2.Optional exclude value - 0 for include, 1 for exclude.+Example : $> echo 0x0000 0x2000 0 > addr_range
+File : addr_single (rw) +Trace Registers : ACVR[idx] +Notes : Set a single address comparator according to addr_idx. This
is used if the address comparator is used as part of eventgeneration logic etc.+Depends : addr_idx +Syntax : 'echo addr1 > addr_single'
+File : addr_start (rw) +Trace Registers : ACVR[idx], VISSCTLR +Notes : Set a trace start address comparator according to addr_idx.
Select comparator in control register.+Depends : addr_idx +Syntax : 'echo addr1 > addr_start'
+File : addr_stop (rw) +Trace Registers : ACVR[idx], VISSCTLR +Notes : Set a trace stop address comparator according to addr_idx.
Select comparator in control register.+Depends : addr_idx +Syntax : 'echo addr1 > addr_stop'
+File : addr_context (rw) +Trace Registers : ACATR[idx,{6:4}] +Notes : Link context ID comparator to address comparator addr_idx +Depends : addr_idx. +Syntax : 'echo ctxt_idx > addr_context'
Where ctxt_idx is the index of the linked context id / vmidcomparator.+File : addr_ctxtype (rw) +Trace Registers : ACATR[idx,{3:2}] +Notes : Input value string. Set type for linked context ID comparator +Depends : addr_idx +Syntax : 'echo type > addr_ctxtype'
Type one of {all, vmid, ctxid, none}+Example : $> echo ctxid > addr_ctxtype
+File : addr_exlevel_s_ns (rw) +Trace Registers : ACATR[idx,{14:8}] +Notes : Set the ELx secure and non-secure matching bits for the
selected address comparator+Depends : addr_idx +Syntax : 'echo val > addr_exlevel_s_ns'
val is a 7 bit value for exception levels to exclude. Inputvalue shifted to correct bits in register.+Example : $> echo 0x4F > addr_exlevel_s_ns
+File : addr_instdatatype (rw) +Trace Registers : ACATR[idx,{1:0}] +Notes : Set the comparator address type for matching. Driver only
supports setting instruction address type.+Depends : addr_idx
+File : addr_cmp_view (ro) +Trace Registers : ACVR[idx, idx+1], ACATR[idx], VIIECTLR +Notes : Read the currently selected address comparator. If part of
address range then display both addresses.+Depends : addr_idx +Syntax : 'cat addr_cmp_view' +Example : $> cat addr_cmp_view
addr_cmp[0] range 0x0 0xffffffffffffffff include ctrl(0x4b00)+File : nr_addr_cmp (ro) +Trace Registers : From IDR4 +Notes : Number of address comparator pairs
+File : sshot_idx (rw) +Trace Registers : None +Notes : Select single shot register set.
+File : sshot_ctrl (rw) +Trace Registers : SSCCR[idx] +Notes : Access a single shot comparator control register. +Depends : sshot_idx +Syntax : 'echo val > sshot_ctrl'
Writes val into the selected control register.+File : sshot_status (ro) +Trace Registers : SSCSR[idx] +Notes : Read a single shot comparator status register +Depends : sshot_idx +Syntax : 'cat sshot_status'
Read status.+Example : $> cat sshot_status
0x1+File : sshot_pe_ctrl (rw) +Trace Registers : SSPCICR[idx] +Notes : Access a single shot PE comparator input control register. +Depends : sshot_idx +Syntax : echo val > sshot_pe_ctrl
Writes val into the selected control register.+File : ns_exlevel_vinst (rw) +Trace Registers : VICTLR{23:20} +Notes : Program non-secure exception level filters. Set / clear NS
exception filter bits. Setting ‘1’ excludes trace from theexception level.+Syntax : 'echo bitfield > ns_exlevel_viinst'
Where bitfield contains bits to set clear for EL0 to EL2+Example : %> echo 0x4 > ns_exlevel_viinst
; Exclude EL2 NS trace.+File : vinst_pe_cmp_start_stop (rw) +Trace Registers : VIPCSSCTLR +Notes : Access PE start stop comparator input control registers
+File : bb_ctrl (rw) +Trace Registers : BBCTLR +Notes : Define ranges that Branch Broadcast will operate in.
Default (0x0) is all addresses.+Depends : BB enabled.
+File : cyc_threshold (rw) +Trace Registers : CCCTLR +Notes : Set the threshold for which cycle counts will be emitted.
Error if attempt to set below minimum defined in IDR3, maskedto width of valid bits.+Depends : CC enabled.
+File : syncfreq (rw) +Trace Registers : SYNCPR +Notes : Set trace synchronisation period. Power of 2 value, 0 (off)
or 8-20. Driver defaults to 12 (every 4096 bytes).+File : cntr_idx (rw) +Trace Registers : none +Notes : Select the counter to access +Syntax : 'echo idx > cntr_idx'
Where idx < nr_cntr+File : cntr_ctrl (rw) +Trace Registers : CNTCTLR[idx] +Notes : Set counter control value +Depends : cntr_idx +Syntax : 'echo val > cntr_ctrl'
Where val is per ETMv4 spec.+File : cntrldvr (rw) +Trace Registers : CNTRLDVR[idx] +Notes : Set counter reload value +Depends : cntr_idx +Syntax : 'echo val > cntrldvr'
Where val is per ETMv4 spec.+File : nr_cntr (ro) +Trace Registers : From IDR5 +Notes : Number of counters implemented.
+File : ctxid_idx (rw) +Trace Registers : None +Notes : Select the context ID comparator to access +Syntax : 'echo idx > ctxid_idx'
Where idx < numcidc+File : ctxid_pid (rw) +Trace Registers : CIDCVR[idx] +Notes : Set the context ID comparator value +Depends : ctxid_idx
+File : ctxid_masks (rw) +Trace Registers : CIDCCTLR0, CIDCCTLR1, CIDCVR<0-7> +Notes : Pair of values to set the byte masks for 1-8 context ID
comparators. Automatically clears masked bytes to 0 in CIDvalue registers.+Syntax : 'echo m3m2m1m0 [m7m6m5m4] > ctxid_masks'
32 bit values made up of mask bytes, where mN represents abyte mask value for Ctxt ID comparator N.Second value not required on systems that have fewer than 4context ID comparators+File : numcidc (ro) +Trace Registers : From IDR4 +Notes : Number of Context ID comparators
+File : vmid_idx (rw) +Trace Registers : None +Notes : Select the VM ID comparator to access. +Syntax : 'echo idx > vmid_idx'
Where idx < numvmidc+File : vmid_val (rw) +Trace Registers : VMIDCVR[idx] +Notes : Set the VM ID comparator value +Depends : vmid_idx
+File : vmid_masks (rw) +Trace Registers : VMIDCCTLR0, VMIDCCTLR1, VMIDCVR<0-7> +Notes : Pair of values to set the byte masks for 1-8 VM ID
comparators. Automatically clears masked bytes to 0 in VMIDvalue registers.+Syntax : 'echo m3m2m1m0 [m7m6m5m4] > vmid_masks'
Where mN represents a byte mask value for VMID comparator N.Second value not required on systems that have fewer than4 VMID comparators.+File : numvmidc (ro) +Trace Registers : From IDR4 +Notes : Number of VMID comparators
+File : res_idx (rw) +Trace Registers : None. +Notes : Select the resource selector control to access. Must be 2 or
higher as selectors 0 and 1 are hardwired.+Syntax : 'echo idx > res_idx'
Where 2 <= idx < nr_resource x 2+File : res_ctrl (rw) +Trace Registers : RSCTLR[idx] +Notes : Set resource selector control value. Value per ETMv4 spec. +Depends : res_idx +Syntax : 'echo val > res_cntr'
Where val is per ETMv4 spec.+File : nr_resource (ro) +Trace Registers : From IDR4 +Notes : Number of resource selector pairs
+File : event (rw) +Trace Registers : EVENTCTRL0R +Notes : Set up to 4 implemented event fields. +Syntax : 'echo ev3ev2ev1ev0 > event'
Where evN is an 8 bit event field. Up to 4 event fields make upthe 32bit input value. Number of valid fields implementationdependent defined in IDR0.+File : event_instren (rw) +Trace Registers : EVENTCTRL1R +Notes : Choose events which insert event packets into trace stream. +Depends : EVENTCTRL0R +Syntax : 'echo bitfield > event_instren'
Where bitfield is up to 4 bits according to number of eventfields.+File : event_ts (rw) +Trace Registers : TSCTLR +Notes : Set the event that will generate timestamp requests. +Depends : TS activated +Syntax : 'echo evfield > event_ts'
Where evfield is an 8 bit event selector.+File : seq_idx (rw) +Trace Registers : None +Notes : Sequencer event register select - 0 to 2
+File : seq_state (rw) +Trace Registers : SEQSTR +Notes : Sequencer current state - 0 to 3.
+File : seq_event (rw) +Trace Registers : SEQEVR[idx] +Notes : State transition event registers +Depends : seq_idx +Syntax : 'echo evBevF > seq_event'
Where evBevF is a 16 bit value made up of two event selectors,evB - back, evF - forwards.+File : seq_reset_event (rw) +Trace Registers : SEQRSTEVR +Notes : Sequencer reset event +Syntax : 'echo evfield > seq_reset_event'
Where evfield is an 8 bit event selector.+File : nrseqstate (ro) +Trace Registers : From IDR5 +Notes : Number of sequencer states (0 or 4)
+File : nr_pe_cmp (ro) +Trace Registers : From IDR4 +Notes : Number of PE comparator inputs
+File : nr_ext_inp (ro) +Trace Registers : From IDR5 +Notes : Number of external inputs
+File : nr_ss_cmp (ro) +Trace Registers : From IDR4 +Notes : Number of Single Shot control registers
+Note: When programming any address comparator the driver will tag the +comparator with a type used - i.e. RANGE, SINGLE, START, STOP. Once this tag +is set, then only the values can be changed using the same sysfs file / type +used to program it.
+Thus:- +% echo 0 > addr_idx ; select address comparator 0 +% echo 0x1000 0x5000 0 > addr_range ; set address range on comparators 0 and 1. +% echo 0x2000 > addr_start ; this will error as comparator 0 is a
; range comparator+% echo 2 > addr_idx ; select address comparator 2 +% echo 0x2000 > addr_start ; this is OK as comparator 2 is unused, +% echo 0x3000 > addr_stop ; this will error as comparator 2 a start
; address comparator+% echo 2 > addr_idx ; select address comparator 3 +% echo 0x3000 > addr_stop ; this is OK
+To remove programming on all the comparators (and all the other hardware) use +the reset parameter:
+% echo 1 > reset
+The ‘mode’ sysfs parameter. +---------------------------
+This is a bitfield selection parameter that sets the overall trace mode for the +ETM. The table below describes the bits, using the defines from the driver +source file, along with a description of the feature these represent. Many +features are optional and therefore dependent on implementation in the +hardware.
+Bit assignements shown below:-
+bit (0) : #define ETM_MODE_EXCLUDE +description : This is the default value for the include / exclude function when
setting address ranges. Set 1 for exclude range. When the modeparameter is set this value is applied to the currently indexedaddress range.+bit (4) : #define ETM_MODE_BB +description : Set to enable branch broadcast if supported in hardware [IDR0].
+bit (5) : #define ETMv4_MODE_CYCACC +description : Set to enable cycle accurate trace if supported [IDR0].
+bit (6) : ETMv4_MODE_CTXID +description : Set to enable context ID tracing if supported in hardware [IDR2].
+bit (7) : ETM_MODE_VMID +description : Set to enable virtual machine ID tracing if supported [IDR2].
+bit (11) : ETMv4_MODE_TIMESTAMP +description : Set to enable timestamp generation if supported [IDR0].
+bit (12) : ETM_MODE_RETURNSTACK +description : Set to enable trace return stack use if supported [IDR0].
+bit (13-14) : ETM_MODE_QELEM(val) +description : ‘val’ determines level of Q element support enabled if
implemented by the ETM [IDR0]+bit (19) : ETM_MODE_ATB_TRIGGER +description : Set to enable the ATBTRIGGER bit in the event control register
[EVENTCTLR1] if supported [IDR5].+bit (20) : ETM_MODE_LPOVERRIDE +description : Set to enable the LPOVERRIDE bit in the event control register
[EVENTCTLR1], if supported [IDR5].+bit (21) : ETM_MODE_ISTALL_EN +description : Set to enable the ISTALL bit in the stall control register
[STALLCTLR]+bit (23) : ETM_MODE_INSTPRIO +description : Set to enable the INSTPRIORITY bit in the stall control register
[STALLCTLR] , if supported [IDR0].+bit (24) : ETM_MODE_NOOVERFLOW +description : Set to enable the NOOVERFLOW bit in the stall control register
[STALLCTLR], if supported [IDR3].+bit (25) : ETM_MODE_TRACE_RESET +description : Set to enable the TRCRESET bit in the viewinst control register
[VICTLR] , if supported [IDR3].+bit (26) : ETM_MODE_TRACE_ERR +description : Set to enable the TRCCTRL bit in the viewinst control register
[VICTLR].+bit (27) : ETM_MODE_VIEWINST_STARTSTOP +description : Set the initial state value of the ViewInst start / stop logic
in the viewinst control register [VICTLR]+bit (30) : ETM_MODE_EXCL_KERN +description : Set default trace setup to exclude kernel mode trace (see note a)
+bit (31) : ETM_MODE_EXCL_USER +description : Set default trace setup to exclude user space trace (see note a)
+Note a) On startup the ETM is programmed to trace the complete address space +using address range comparator 0. ‘mode’ bits 30 / 31 modify this setting to +set EL exclude bits for NS state in either user space (EL0) or kernel space +(EL1) in the address range comparator. (the default setting excludes all +secure EL, and NS EL2)
+Once the reset parameter has been used, and/or custom programming has been +implemented - using these bits will result in the EL bits for address +comparator 0 being set in the same way.
+Note b) Bits 2-3, 8-10, 15-16, 18, 22, control features that only work with +data trace. As A profile data trace is architecturally prohibited in ETMv4, +these have been omitted here. Possible uses could be where a kernel has +support for control of R or M profile infrastructure as part of a heterogeneous +system.
+Bits 17, 28-29 are unused.
2.17.1