On Thu, 17 Jan 2019 at 19:27, Peter Maydell <peter.mayd...@linaro.org> wrote: > > On Thu, 17 Jan 2019 at 10:58, Julia Suvorova <jus...@mail.ru> wrote: > > > > On 17.01.2019 13:13, Stefan Hajnoczi wrote: > > > generic_loader_reset() calls cpu_reset(s->cpu) followed by > > > CPUClass->set_pc(s->cpu, s->addr). > > > > > > ARM's arm_cpu_set_pc() doesn't special-case the Thumb bit (that's only > > > done in arm_cpu_reset()) so we end up with an invalid PC for Thumb mode > > > addresses. > > > > > > Maybe the following arm_cpu_reset() code should be moved to > > > arm_cpu_set_pc(): > > > > > > env->regs[15] = initial_pc & ~1; > > > env->thumb = initial_pc & 1; > > > > > > Then arm_cpu_reset() can call arm_cpu_set_pc() instead of duplicating > > > this code. > > > > No, set_pc() is called in cpu_tb_exec() to restore the PC value and > > therefore should not be changed. > > The set_pc hook is also called for the gdbstub 'c' and 's' packets > if they supply an address. I am not sure what the correct behaviour > there is (it might be tricky to find out or test, because the > 'c' and 's' packets are deprecated in favour of vCont which doesn't > allow the address argument at all, and recent gdb neither emits > 'c addr' nor supports it in its gdbserver implementation).
I asked Linaro's gdb developer, and they thought that the gdb 'c addr' behaviour ought to be "look at bit 0 and switch to Thumb or Arm mode accordingly". thanks -- PMM
