On 25 June 2014 05:08, Hunter Laux <hunterl...@gmail.com> wrote: > This instruction space is guaranteed to be undefined. > ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx > Thumb: 1101 1110 xxxx xxxx > > The breakpoint instructions were selected from this instruction space. > Linux traps the illegal instruction and sends a SIGTRAP if it is a breakpoint. > > Here is the Linux implementation: > http://lxr.free-electrons.com/source/arch/arm/kernel/ptrace.c#L221 > > Signed-off-by: Hunter Laux <hunterl...@gmail.com> > --- > linux-user/main.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/linux-user/main.c b/linux-user/main.c > index 900a17f..91f2681 100644 > --- a/linux-user/main.c > +++ b/linux-user/main.c > @@ -688,11 +688,29 @@ void cpu_loop(CPUARMState *env) > uint32_t opcode; > int rc; > > + const uint32_t arm_bkpt_mask = 0x0FFFFFFF; > + const uint32_t arm_bkpt = 0x07F001F0; > + const uint32_t arm_bkpt_thumb_mask = 0x0000FFFF; > + const uint32_t arm_bkpt_thumb = 0x0000DE01; > + const uint32_t arm_bkpt_thumb2_mask = 0xFFFFFFFF; > + const uint32_t arm_bkpt_thumb2 = 0xF7F0A000; > + > /* we handle the FPU emulation here, as Linux */ > /* we get the opcode */ > /* FIXME - what to do if get_user() fails? */ > get_user_code_u32(opcode, env->regs[15], env->bswap_code); > > + if (env->thumb) { > + if ((opcode & arm_bkpt_thumb_mask) == arm_bkpt_thumb > + || (opcode & arm_bkpt_thumb2_mask) == > arm_bkpt_thumb2) { > + goto excp_debug; > + } > + } else { > + if ((opcode & arm_bkpt_mask) == arm_bkpt) { > + goto excp_debug; > + } > + } > + > rc = EmulateAll(opcode, &ts->fpa, env); > if (rc == 0) { /* illegal instruction */ > info.si_signo = SIGILL;
This shouldn't be necessary, because our instruction decoder causes the BKPT instructions to generate an EXCP_BKPT (see target-arm/translate.c). So we should never go through this code path for these instructions... thanks -- PMM
