On 9 October 2015 at 14:59, Sergey Fedorov <serge.f...@gmail.com> wrote: > On 08.10.2015 21:40, Peter Maydell wrote: >> Annoying corner case which I don't think we need to handle necessarily: >> if you set a breakpoint on a 32-bit Thumb instruction which spans a page >> boundary, and the second page is not present, we will end up taking the >> page fault when I think we should take the breakpoint. I can't think >> of a way to get that right, so just commenting that it isn't handled >> right would do. > > Could you please point out the piece of code which will generate the > page fault? Maybe I will give it a thought :)
When you call arm_ldl_code() and friends, they will end up longjmp()ing out of the codegen phase if the load faults. This then turns into a guest-visible fault in the usual way. To avoid this you'd need to instead call functions which return a transaction status, but then: (a) you need to restructure the translate.c code so it can deal with the idea of backing out if the instruction isn't actually present (b) this still wouldn't work for linux-user mode, where we don't have any way to say "do a memory access, but let me know if it would fail rather than longjmping" thanks -- PMM
