Date: Wed, 1 May 2002 11:17:58 -0700 From: Marcel Moolenaar <marcel@xcllnt.net> To: Doug Rabson <dfr@nlsystems.com> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/ia64/ia64 exception.s src/sys/ia64/include frame.h Message-ID: <20020501181758.GB415@athlon.pn.xcllnt.net> In-Reply-To: <200205010940.33776.dfr@nlsystems.com> References: <200204300637.g3U6bQc25956@freefall.freebsd.org> <20020430165257.M25863-100000@herring.nlsystems.com> <20020430195757.GA70203@gauss.cup.hp.com> <200205010940.33776.dfr@nlsystems.com>
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On Wed, May 01, 2002 at 09:40:33AM +0100, Doug Rabson wrote: > On Tuesday 30 April 2002 8:57 pm, Marcel Moolenaar wrote: > > On Tue, Apr 30, 2002 at 04:53:59PM +0100, Doug Rabson wrote: > > > On Mon, 29 Apr 2002, Marcel Moolenaar wrote: > > > > marcel 2002/04/29 23:37:25 PDT > > > > > > > > Modified files: > > > > sys/ia64/ia64 exception.s > > > > sys/ia64/include frame.h > > > > Log: > > > > Add ar.lc and ar.ec to the trapframe. These are not saved for > > > > syscalls, only for exceptions. > > > > > > I was kind-of relying on the C calling conventions saving/restoring these > > > as needed. > > > > ar.lc is callee saved. We have to do it even for the syscall case. > > ar.ec is automatic as part of the call/return mechanism. We need to > > explicitly save it only if it's possible to have syscalls inlined. > > What I actually meant by that statement was that since the exception entry > path didn't disturb the value of ar.lc (or ar.ec for that matter) and that it > can rely on the value being preserved by the higher level handlers (e.g. > trap, interrupt, syscall etc), it can also rely on the value in > exception_restore being the user's value. That is correct, provided we save them on context switches, right? BTW: The reason I added them was for ptrace(2). -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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