genode/repos/base-linux/include
Norman Feske a4115cfea9 base-linux: discharge timestamp on AARCH64
The kernel-agnostic 'Trace::timestamp' function for arm_64 executes the
'mrs %0, pmccntr_el0' instruction, which is not permitted for user-level
programs on Linux. This patch shadows the generic timestamp.h header
with dummy that returns zero. This return value prompts the timeout
framework to disable the interpolation of time based on timestamps. This
avoid the illegal-instruction abort but comes with two llimitations:

First, time measurements are effectlively limited to a granulariry of 1
millisecond (deliberately constrained by the timer driver).

The quirk is applied when using the base-linux API. Should a generic
application (that uses the base API only) call 'Trace::timestamp'
directly, the illegal instruction is executed.

Issue #4136
2021-05-10 11:17:20 +02:00
..
spec/arm_64/trace base-linux: discharge timestamp on AARCH64 2021-05-10 11:17:20 +02:00