HWT: ARM CoreSight support

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Summary

• Add ARM Coresight (SoC-400) support to HWT framework
• Pipeline build code added

Test Plan

Tested on ARM Morello platform.

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Add CORESIGHT_DEBUG macro.

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Wrap long lines.

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Fix comment.

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Provide the name of backend needed for registration in HWT framework.

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clean up

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Interface to HWT changed

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morello-dts included for test

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Regenerate

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Make coresight optional. Depends on hwt

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coresight_setup() method added

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regenerate

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hwt_backend interface changed

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Kernel-mode tracing support added.

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allow tracing multiple cpus in system mode

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Regenerate

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ability to build as a module

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Fix tracing cpu_id > 0

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regenerate

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regenerate

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Regenerate

[zachary.leaf_arm.com]

sys/arm64/coresight/coresight.c

67

Should we dynamically allocate this based on mp_ncpus instead, especially since MAXCPU is being bumped to 1024? I think it would make sense to do that in coresight_backend_init and then can free() at the end of coresight_backend_deinit.

This is what I'm doing for SPE at the moment.

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rebase for freebsd

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Pass ctx to backend_deinit().

[andrew]

This doesn't build when I add hwt and coresight to my kernel config

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Regen

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Regen

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Regenerate

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Due to pipeline design Coresight components could not be used for more than 1 concurrent tracing sessions.
Atomic counter of sessions added and limited to 1.

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In D40477#957268, @andrew wrote:

This doesn't build when I add hwt and coresight to my kernel config

Could you try again? A change in modules/Makefile was missing