Date: Sun, 17 Nov 2002 05:13:58 -0800 From: Alfred Perlstein <bright@mu.org> To: Doug Rabson <dfr@nlsystems.com> Cc: Marcel Moolenaar <marcel@xcllnt.net>, Daniel Eischen <eischen@pcnet1.pcnet.com>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/lib/libc_r/arch/ia64 _atomic_lock.S Message-ID: <20021117131358.GK6882@elvis.mu.org> In-Reply-To: <200211171025.00359.dfr@nlsystems.com> References: <20021116185125.GB618@dhcp01.pn.xcllnt.net> <Pine.GSO.4.10.10211161411500.14431-100000@pcnet1.pcnet.com> <20021116195821.GB1058@dhcp01.pn.xcllnt.net> <200211171025.00359.dfr@nlsystems.com>
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* Doug Rabson <dfr@nlsystems.com> [021117 02:25] wrote: > On Saturday 16 November 2002 7:58 pm, Marcel Moolenaar wrote: > > On Sat, Nov 16, 2002 at 02:13:19PM -0500, Daniel Eischen wrote: > > > On Sat, 16 Nov 2002, Marcel Moolenaar wrote: > > > > If you want me to send patches, let me know. I'm trying to figure > > > > out what to do now that the *context functions have been turned > > > > into syscalls. It complicates things... > > > > > > I'm working on converting libc_r to use *context() so don't > > > worry about doing it yourself. > > > > Cool! > > > > I hope to have the *context syscalls next week. I've decided to > > not attack the problem head on, because we don't have time to > > fix the infrastructure for it (we need to unwind to recreate the > > context). Instead, I hope to hack-up a workable solution from an > > ABI breaking change. The ABI breaker allows us to have lightweight > > syscalls, which we permanently want. So, doing that now is very > > attractive. The intend is to implement the *context syscalls as > > lightweight syscalls in a very hackish way. This serves as an > > experiment as well as solving an immediate problem. Let's hope > > it works out... > > So you intend to recognise the context calls in the syscall wrapper and > special-case them? This would work but it would also work for > heavyweight syscalls. I'm still worried about how you are going to > flush the user's register stack safely from kernel mode. I'm probably being dense, but doesn't the ABI specify behaviour such that one may not use stack space past the frame pointer (equivelant of ebp on i386) so this should be doable, right? Basically, as long as the frame pointer is moved before the space is used it's safe, right? -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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