HWPMC tracing support (5) -- Intel PT

[br]

use osd(9)

[br]

Fix build

[br]

don't take additional reference to object. We already taking one in pmc_mmap_single()

[br]

Regenerate patch

[br]

merge changes from upstream

[br]

regenerate

[br]

regenerate

[markj]

sys/dev/hwpmc/hwpmc_pt.c

162

I don't have the XFEATURE_ENABLED_PT definition. Where is it?

[br]

Include sys/x86/include/specialreg.h

[br]

sys/dev/hwpmc/hwpmc_pt.c

162

I missed the diff to specialreg.h. Added

[markj]

sys/dev/hwpmc/hwpmc_pt.c

173

This assumes that lazy_fpu_switch is configured, which is no longer the default behaviour.

I suspect that we should really be saving/restoring PT state in the main kernel.

[kib]

sys/dev/hwpmc/hwpmc_pt.c

173

You mean, on context switch ? I do not think it is needed.

You can save previous value of CR0.TS and only set it when needed at the end.
To be modular, code should restore previous XSS mask after doing it job.
The code must assert that we are in critical section (or with disabled interrupts).
Why is pt_xsave_mask a variable instead of literal symbol ?

[br]

fix style

[br]

Regenerate patch.

[br]

sys/dev/hwpmc/hwpmc_pt.c

173

• pt_xsave_mask changed a literal symbol
• Assertion added
• Original XSS mask restored