pmu_init() register its event checking the pm_event::supported()
handler. For INST_RETIRED, the event is only registered and the
bit enabled in the PMU Common Event Identification register when
icount is enabled as ICOUNT_PRECISE.
PMU events are TCG-only, hardware accelerators handle them
directly. Unfortunately we register the events in non-TCG builds,
leading to linking error such:
ld: Undefined symbols:
_icount_to_ns, referenced from:
_instructions_ns_per in target_arm_helper.c.o
clang: error: linker command failed with exit code 1 (use -v to see
invocation)
As a kludge, give a hint to the compiler by asserting the
pm_event::get_count() and pm_event::ns_per_count() handler will
only be called under this icount mode.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
As discussed in
CAFEAcA-HVf8vWLzmdStEo2NrSKQdZV612rBjiaj-gLW4vXyvpA@mail.gmail.com/">https://lore.kernel.org/qemu-devel/CAFEAcA-HVf8vWLzmdStEo2NrSKQdZV612rBjiaj-gLW4vXyvpA@mail.gmail.com/
better would be to restrict the PMU events to TCG, but this is
out of the scope of this series.