loader.efi(8): the amd64 loader doesn't do protected mode
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Authored by vexeduxr on Sun, Jun 14, 3:37 AM.

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imp
kib
jrtc27
ziaee
manu

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rGe3aba9eaf02e: loader.efi(8): the amd64 loader doesn't do protected mode
rGb8a7dd6ba540: loader.efi(8): the amd64 loader doesn't do protected mode
rGf771deb193d5: loader.efi(8): the amd64 loader doesn't do protected mode

Summary

The amd64 UEFI loader executes in long mode, not protected mode.

MFC after: 3 days

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rG FreeBSD src repository

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Buildable 73861
Build 70744: arc lint + arc unit

Event Timeline

vexeduxr created this revision.Sun, Jun 14, 3:37 AM

Herald added a reviewer: manu. · View Herald TranscriptSun, Jun 14, 3:37 AM

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vexeduxr requested review of this revision.Sun, Jun 14, 3:37 AM

Harbormaster completed remote builds in B73861: Diff 179708.Sun, Jun 14, 3:37 AM

vexeduxr added a child revision: D57569: loader.efi(8): document the ia32 loader.Sun, Jun 14, 3:38 AM

why not change the word 'protected' to 'long'?

In D57568#1319451, @kib wrote:

why not change the word 'protected' to 'long'?

I'm not sure how the CPU mode is relevant to the rest of the text. Shouldn't the CPU be susceptible to faults regardless of the mode?

In D57568#1319454, @vexeduxr wrote:

In D57568#1319451, @kib wrote:

why not change the word 'protected' to 'long'?

I'm not sure how the CPU mode is relevant to the rest of the text. Shouldn't the CPU be susceptible to faults regardless of the mode?

It is quite involved to make CPU fault in real mode. In VM86 mode it is somewhat easier but still not straight. The mention of the mode is to compare it with the old pre-EFI BIOS where loader practically cannot cause CPU faults.

Keep the sentence intact but change x86 protected mode to 64-bit long mode.

Harbormaster completed remote builds in B73866: Diff 179731.Sun, Jun 14, 10:25 AM

In D57568#1319455, @kib wrote:

In D57568#1319454, @vexeduxr wrote:

In D57568#1319451, @kib wrote:

why not change the word 'protected' to 'long'?

I'm not sure how the CPU mode is relevant to the rest of the text. Shouldn't the CPU be susceptible to faults regardless of the mode?

It is quite involved to make CPU fault in real mode. In VM86 mode it is somewhat easier but still not straight. The mention of the mode is to compare it with the old pre-EFI BIOS where loader practically cannot cause CPU faults.