https://bugs.kde.org/show_bug.cgi?id=369509
Peter Maydell <peter.mayd...@linaro.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |peter.mayd...@linaro.org
--- Comment #8 from Peter Maydell <peter.mayd...@linaro.org> ---
Feature identification via SIGILL is definitely not recommended for either
32-bit or 64-bit Arm. There are cases where it will give you the wrong answer
(eg if the hardware supports the instruction but support is disabled by the
kernel because of some erratum or because the kernel has had support compiled
out). You have two recommended methods of detection: (1) hwcaps; or (2) for
64-bit only, you can directly access the ID registers via MRS and rely on the
kernel to emulate this as documented in
https://www.kernel.org/doc/Documentation/arm64/cpu-feature-registers.txt. (You
might want some kind of fallback for older kernels which don't support that; I
forget when it came in.)
PS: does valgrind implement 'emulate the kernel emulation of those ID
registers' for an arm64 guest binary?
--
You are receiving this mail because:
You are watching all bug changes.
