Messages in this thread | | | Subject | Re: [PATCH] kprobes for s390 architecture | From | Martin Schwidefsky <> | Date | Tue, 27 Jun 2006 13:56:11 +0200 |
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On Wed, 2006-06-21 at 10:15 -0700, Mike Grundy wrote: > On Wed, Jun 21, 2006 at 06:38:40PM +0200, Martin Schwidefsky wrote: > > On Tue, 2006-06-20 at 21:28 -0700, Mike Grundy wrote: > > > Hi Martin - This patch implements the suggestions from your review. There were > > > a couple points I wanted to go over: > > > > There are some more instructions missing that need fixup: > > > > "brxh" 0x84??????, "brxle" 0x85??????, "brc" 0xa7?4????, > > > > "brct" 0xa7?6????, "brctg" 0xa7?7????, "bctgr" 0xb946????, > > > > "brxhg" 0xec????????44 and "brxlg" 0xec??????45. > > > Since all of these are relative branches, and they don't save the psw, the > > > standard clean up of adjusting the original psw by the offset from the out of > > > line address after single step. Unless I'm just being dense :-) > > > > All of these are conditional branches, if the branch is not taken you > > have to do a cleanup. > The reason I have a special cleanup for the other branches is the easy way to > tell if the branch wasn't taken is the pswa = orig pswa + instruction length. > The relative branches get cleaned up the same way if the branch was taken or > not, pswa = probe_addr + (out of line end psw - out of line start psw). These > are all relative branches and while they need cleanup, they don't get treated > differently based on the branch status.
So you are always doing a sort of branch cleanup, even for non-branch instructions. Seems reasonable, since non-branch instructions don't branch and the standard cleanup logic can deal with.
> > You misunderstood me here. I'm not talking about storing the same piece > > of data to memory on each processor. I'm talking about isolating all > > other cpus so that the initiating cpu can store the breakpoint to memory > Yep, I misunderstood that. The serialization is the point, not the replacement > of a word in memory.
Exactly.
-- blue skies, Martin.
Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH
"Reality continues to ruin my life." - Calvin.
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