Record cr2, error_code, and exception_index. That last means
that we must exit to cpu_loop ourselves, instead of letting
exception_index being overwritten.
Use the maperr parameter to properly set PG_ERROR_P_MASK.
Reviewed by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>