fix: efirt: use compiler ms_abi for EFI runtime calls on amd64
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Authored by guest-seuros on Wed, Mar 4, 10:37 PM.

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kib
imp
kevans
obiwac

Summary

The assembly trampoline in efi_rt_arch_call had a stack alignment bug for 5-argument EFI calls (GetVariable, SetVariable):

it computed max(N,4)*8 = 40 bytes of stack space, leaving RSP 8-byte aligned instead of the 16 required by the MS x64 ABI.

Firmware compiled with SSE (for example coreboot/EDK2) uses MOVAPS for callee-saved XMM register spills, causing #GP on every GetVariable/SetVariable call.

Replaced the assembly ABI conversion with efi_rt_dispatch(). The assembly trampoline is kept only for fault recovery, delegating the actual call to the C function.

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Repository

rG FreeBSD src repository

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Build Status

Buildable 71188
Build 68071: arc lint + arc unit

Event Timeline

guest-seuros created this revision.Wed, Mar 4, 10:37 PM

guest-seuros held this revision as a draft.

Herald added a subscriber: imp. · View Herald TranscriptWed, Mar 4, 10:37 PM

Harbormaster completed remote builds in B71188: Diff 173157.Wed, Mar 4, 10:38 PM

guest-seuros edited the summary of this revision. (Show Details)Wed, Mar 4, 10:40 PM

guest-seuros added reviewers: kib, imp, kevans, obiwac.

guest-seuros published this revision for review.Thu, Mar 5, 12:00 AM

Could you try the patch below instead?

diff --git a/sys/amd64/amd64/efirt_support.S b/sys/amd64/amd64/efirt_support.S
index 98063ad561aa..54578f573750 100644
--- a/sys/amd64/amd64/efirt_support.S
+++ b/sys/amd64/amd64/efirt_support.S
@@ -58,6 +58,7 @@ ENTRY(efi_rt_arch_call)
 	cmovbl	%eax, %ecx
 	shll	$3, %ecx
 	subq	%rcx, %rsp
+	andq	$~0xf, %rsp
 
 	cmpl	$0, %ebx
 	jz	1f