Date: Wed, 2 Aug 2017 19:19:44 -0500 From: Bobby Bingham <koorogi@...rogi.info> To: musl@...ts.openwall.com Subject: Re: possible bug in setjmp implementation for ppc64 On Wed, Aug 02, 2017 at 10:46:12AM -0400, Rich Felker wrote: > On Wed, Aug 02, 2017 at 08:38:25AM -0500, Bobby Bingham wrote: > Whether the call to longjmp/siglongjmp was local or not is irrelevant. > It's only whether the original call to setjmp/sigsetjmp was local or > not that's relevant. And in either case I'm pretty sure it suffices to I think I was treating whether longjmp is called locally as a proxy for whether setjmp was called locally. But of course that doesn't work. I think we're on the same page now. > restore the saved value to both *(r1+24) and r2. Per the ABI, *(r1+24) > can't be used for any purpose except saving the TOC, so upon return > from setjmp, the caller's only options are to treat the value at > *(r1+24) as indeterminate or assume it contains the TOC pointer. > Likewise for r2, if the call was non-local, r2 is call-clobbered so it > doesn't matter what it contains after return, and if the call was > local, r2 is expected to contain the caller's TOC pointer. > > Rich
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