2c991e408d
Markus reported that BTS is sporadically missing the tail of the trace
in the perf_event data buffer: [decode error (1): instruction overflow]
shown in GDB; and bisected it to the conversion of debug_store to PTI.
A little "optimization" crept into alloc_bts_buffer(), which mistakenly
placed bts_interrupt_threshold away from the 24-byte record boundary.
Intel SDM Vol 3B 17.4.9 says "This address must point to an offset from
the BTS buffer base that is a multiple of the BTS record size."
Revert "max" from a byte count to a record count, to calculate the
bts_interrupt_threshold correctly: which turns out to fix problem seen.
Fixes:
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| .. | ||
| boot | ||
| configs | ||
| crypto | ||
| entry | ||
| events | ||
| hyperv | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| purgatory | ||
| ras | ||
| realmode | ||
| tools | ||
| um | ||
| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||
| Makefile.um | ||