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Differential D51147

amd64/efirt: always map the first page
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Authored by vexeduxr on Thu, Jul 3, 1:58 PM.
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imp
kib
markj
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rG4add1a7a46b5: amd64/efirt: always map the first page
Summary

Some BIOSes tend to access physical address zero when executing runtime
EFI functions. Allow the first page to be mapped through a tunable.

PR: 287422

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rG FreeBSD src repository
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Event Timeline

vexeduxr requested review of this revision.Thu, Jul 3, 1:58 PM
vexeduxr created this revision.
Harbormaster completed remote builds in B65188: Diff 157882.Thu, Jul 3, 1:58 PM
vexeduxr added inline comments.Thu, Jul 3, 1:59 PM
sys/amd64/amd64/efirt_machdep.c
294

I think this name could be a little better. Suggestions welcome.

kib added inline comments.Fri, Jul 4, 7:42 AM
sys/amd64/amd64/efirt_machdep.c
294

I propose to eliminate the tunable at all. Always map page @ phys 0.

299

I do not think this is a good choice. Just assume WB, I think it is how all x86 machines are organized.

Or be honest and try to search the map to see if zero fits into any region. Actually I think this is the best action, if page at zero already included into rt or boot region. You can check this while iterating over the regions for which the mappings are created, and if not recorded as done, do the special handling for page at zero.

vexeduxr retitled this revision from amd64/efirt: allow the first page to be mapped to amd64/efirt: always map the first page.Fri, Jul 4, 1:30 PM
vexeduxr updated this revision to Diff 157938.Fri, Jul 4, 1:31 PM

Remove the tunable, always map the first page.

Assume Writeback for the first page.

Harbormaster completed remote builds in B65203: Diff 157938.Fri, Jul 4, 1:31 PM
vexeduxr mentioned this in D51146: amd64: allow the mapping of other regions for efirt.Fri, Jul 4, 1:37 PM
kib accepted this revision.Fri, Jul 4, 6:01 PM
This revision is now accepted and ready to land.Fri, Jul 4, 6:01 PM
imp accepted this revision.Fri, Jul 4, 6:17 PM
Closed by commit rG4add1a7a46b5: amd64/efirt: always map the first page (authored by vexeduxr). · Explain WhySun, Jul 6, 7:28 PM
This revision was automatically updated to reflect the committed changes.
vexeduxr added a commit: rG4add1a7a46b5: amd64/efirt: always map the first page.

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sys/
amd64/
amd64/
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sys/amd64/amd64/efirt_machdep.c

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