x86-64: fix thread tracing
The current instrumentation point for CONFIG_TRACING added in
PR #28512 had two problems:
- If userspace and KPTI are enabled, the tracing point is simply
never run if we are resuming a user thread as the
z_x86_trampoline_to_user function is jumped to and calls
'iret' from there
- Only %rdi is being saved. However, at that location, *all*
caller-saved registers are in use as they contain the
resumed thread's context
Simplest solution is to move this up near where we update page
tables. The #ifdefs are used to make sure we don't push/pop
%rdi more than once. At that point in the code only %rdi
is in use among the volatile registers.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
1 file changed
