Date: Thu, 24 Feb 2000 08:58:54 -0800 (PST) From: John Polstra <jdp@polstra.com> To: dfr@nlsystems.com Cc: alpha@freebsd.org Subject: Re: pcb_onfault bug on alpha? Message-ID: <200002241658.IAA39924@vashon.polstra.com> In-Reply-To: <Pine.BSF.4.10.10002240856070.54384-100000@tecra.nlsystems.com> References: <Pine.BSF.4.10.10002240856070.54384-100000@tecra.nlsystems.com>
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On a related topic, do you have any idea why they did all this
".set noat" nonsense in copyout instead of simply using t0 to set
pcb_onfault as is done elsewhere? I can't see any reason why they'd
need to preserve t0 at this point.
NESTED(copyout, 3, 16, ra, 0, 0)
LDGP(pv)
lda sp, -16(sp) /* set up stack frame */
stq ra, (16-8)(sp) /* save ra */
ldiq t0, VM_MAXUSER_ADDRESS /* make sure that dest addr */
cmpult a1, t0, t1 /* is in user space. */
beq t1, copyerr /* if it's not, error out. */
lda v0, copyerr /* set up fault handler. */
.set noat
ldq at_reg, curproc
ldq at_reg, P_ADDR(at_reg)
stq v0, U_PCB_ONFAULT(at_reg)
.set at
CALL(bcopy) /* do the copy. */
.set noat
ldq at_reg, curproc /* kill the fault handler. */
ldq at_reg, P_ADDR(at_reg)
stq zero, U_PCB_ONFAULT(at_reg)
.set at
ldq ra, (16-8)(sp) /* restore ra. */
lda sp, 16(sp) /* kill stack frame. */
mov zero, v0 /* return 0. */
RET
END(copyout)
John
--
John Polstra jdp@polstra.com
John D. Polstra & Co., Inc. Seattle, Washington USA
"Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa
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