K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2001-04-17T02:44:35.000000Z
K 7
svn:log
V 555
In exception_return(), test for usermode before testing the IPL to see if
we should call ast().  This allows us to branch to a separate Lkernelret
label so we can fixup the saved t7 register in the trapframe.  Otherwise
we can run into a problem on SMP systems where a process is interrupted by
a trap or interrupt on one CPU, migrates to another CPU, and then returns
with the t7 in the stack clobbering the CPU's t7.  As a result, two CPU's
would both point to the same per-CPU data and things would go downhill from
there.

Sleuthing help by:	gallatin

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