On Fri, Jun 08, 2012 at 04:38:17PM +1000, Michael Ellerman wrote: > On Fri, 2012-06-08 at 11:49 +0530, Ananth N Mavinakayanahalli wrote: > > On Fri, Jun 08, 2012 at 04:17:44PM +1000, Michael Ellerman wrote: > > > On Fri, 2012-06-08 at 11:31 +0530, Ananth N Mavinakayanahalli wrote: > > > > On Fri, Jun 08, 2012 at 03:51:54PM +1000, Michael Ellerman wrote: > > > > > On Fri, 2012-06-08 at 10:06 +0530, Ananth N Mavinakayanahalli wrote: > > > > > > > > But MSR_PR=1 and hence emulate_step() will return -1 and hence we will > > > > end up single-stepping using user_enable_single_step(). Same with rfid. > > > > > > Right. But that was exactly Jim's point, you may be asked to emulate > > > those instructions even though you wouldn't expect to see them in > > > userspace code, so you need to handle it. > > > > > > Luckily it looks like emulate_step() will do the right thing for you. > > > It'd be good to test it to make 100% sure. > > > > Sure. Will add that check and send v2. > > Sorry I didn't mean add a test in the code, I meant construct a test > case to confirm that it works as expected.
Michael, I just hand-coded the instr to emulate_step() and here are the results: MSR_PR is set insn = 7c600124, ret = 0 /* mtmsr */ insn = 7c600164, ret = 0 /* mtmsrd */ insn = 4c000024, ret = -1 /* rfid */ insn = 4c000064, ret = 0 /* rfi */ Also verified that standalone programs with those instructions in inline asm will die with a SIGILL. So, for mtmsr, mtmsrd and rfi, we have to single-step them which will result in a SIGILL in turn. Ananth _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
