Re: Base GDB tracing 32bit applications on amd64 kernel (with 64bit debugger) part 1)

[Maxime Villard <max%m00nbsd.net@localhost>]

Le 24/06/2019 à 21:51, maya%netbsd.org@localhost a écrit :
> cc'ing maxv@ who is the author of some of the commits,

These commits date back to when I was writing USER_LDT support. In order to
get that support, I changed the segregs model, and this caused non-obvious
behavior changes. A few areas didn't look particularly functional, and I
preferred to drop them temporarily not to introduce bugs. Then it turned
out no one was interested in working on USER_LDT (back then), and I kind of
lost interest and didn't work further on that either.

In order to reintroduce debugging:

 - The code to handle 32bit LWPs from 64bit LWPs should be in separate
   functions.
 - The checks on 32bit LWPs should allow non-default segregs -- or we can
   say it doesn't matter, and it'll mean for now we won't be able to debug
   Wine32.
 - Xen is causing some problems here (as usual...). See process_write_regs(),
   we are resetting the ss/cs registers to the default values. Yet in
   cpu_setmcontext32 we suddenly don't care about resetting ss/cs to the
   default values. It's not clear to me which side is incorrect.