Messages in this thread | | | Date | Sat, 05 Jul 2008 20:07:03 -0700 | From | "H. Peter Anvin" <> | Subject | Re: Regression: boot failure on AMD Elan TS-5500 |
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Eric W. Biederman wrote: > Sean Young <sean@mess.org> writes: > >> On Mon, Jun 30, 2008 at 02:52:10PM -0700, Jeremy Fitzhardinge wrote: >>> It's a bit odd that the boot loader neglected to set up ds properly, but >>> changing the testb line to >>> >>> testb $(1<<6), %cs:BP_loadflags(%esi) >>> >>> should work. (Or perhaps a %ss: override would be better?) >> Yup, it does (%cs: prefix). > > Guys I have a fuzzy memory of reads and definitely writes through %cs not working, > on some processor models. i386? >
You can never write through %cs in protected mode.
You can read through %cs: in protected mode unless %cs contains an execute-only descriptor.
-hpa
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