From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by mx.groups.io with SMTP id smtpd.web08.6156.1610013298650227365 for ; Thu, 07 Jan 2021 01:54:58 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=EEo6zGGf; spf=pass (domain: redhat.com, ip: 63.128.21.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610013297; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xly42K+LnxPvws7eynhyIGFFXj7srbIgzu3sc2Ul+FE=; b=EEo6zGGft30iFtN0vxXzw3XGxEZ7AoY6lpkMzjUe/fYkz8iEz3vvmbBadvoIj1s0I5O4T7 q2WFjlGs/C4PDS6TMHmSFj+6aow0YcSZGmE7emjuQtuXM/p/lIOnUwcEHj2uUxJQxzGEg6 iO9QGn0892jSOaHmwlKWLGOmD2A+jfY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-170---85ekiXNm2pyMs5aVjO7g-1; Thu, 07 Jan 2021 04:54:53 -0500 X-MC-Unique: --85ekiXNm2pyMs5aVjO7g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 64BF8801817; Thu, 7 Jan 2021 09:54:52 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-114-119.ams2.redhat.com [10.36.114.119]) by smtp.corp.redhat.com (Postfix) with ESMTP id D8FCB1346D; Thu, 7 Jan 2021 09:54:50 +0000 (UTC) Subject: Re: UefiCpuPkg/CpuDxe: Fix boot error To: "Kinney, Michael D" , "Dong, Guo" , "devel@edk2.groups.io" Cc: "Dong, Eric" , "Ni, Ray" , "Kumar, Rahul1" References: From: "Laszlo Ersek" Message-ID: Date: Thu, 7 Jan 2021 10:54:49 +0100 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 01/07/21 02:00, Kinney, Michael D wrote: > Guo, > > Yes. Using the following looks like the correct solution: > > o64 retf I agree; these operand size prefixes are one of the strengths of NASM. Thanks! Laszlo > > Thanks, > > Mike > >> -----Original Message----- >> From: Dong, Guo >> Sent: Wednesday, January 6, 2021 2:07 PM >> To: devel@edk2.groups.io; Kinney, Michael D >> Cc: Dong, Eric ; Ni, Ray ; lersek@redhat.com; Kumar, Rahul1 >> >> Subject: FW: UefiCpuPkg/CpuDxe: Fix boot error >> >> >> Hi Mike, >> >> I just did a test with retfq, it looks the compiler will take 'retfq' as a label with a warnig: >> "CpuAsm.iii:26: warning: label alone on a line without a colon might be in error" >> >> CpuAsm.nasm is the source file. >> Both CpuAsm.iii and CpuAsm.obj are from the build folder. >> CpuAsm_dasm.txt is the dasm file using objdump. >> >> I am using "NASM version 2.12.01rc2 compiled on Mar 7 2016". >> BTW, if using "O64 retf" instead of "retfq", the generated obj matches with DB one. >> Do you prefer using " O64 retf" comparing with "DB 0x48, 0xcb"? >> >> Thanks, >> Guo >> >>> -----Original Message----- >>> From: Kinney, Michael D >>> Sent: Tuesday, January 5, 2021 7:01 PM >>> To: Dong, Guo ; devel@edk2.groups.io; Kinney, Michael >>> D >>> Cc: Dong, Eric ; Ni, Ray ; >>> lersek@redhat.com; Kumar, Rahul1 >>> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error >>> >>> Hi Guo, >>> >>> Could be the port from MASM to NASM did not check to see if NASM supported >>> the instruction. >>> >>> You can verify the NASM disassembly to make sure it matches the DB bytes. >>> >>> Mike >>> >>>> -----Original Message----- >>>> From: Dong, Guo >>>> Sent: Tuesday, January 5, 2021 4:51 PM >>>> To: Kinney, Michael D ; devel@edk2.groups.io >>>> Cc: Dong, Eric ; Ni, Ray ; >>> lersek@redhat.com; Kumar, Rahul1 >>>> >>>> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error >>>> >>>> >>>> Hi Mike, >>>> >>>> Thanks for the comments. I will remove DB and submit a new patch. >>>> I used DB because retfq is used in EDK2 only in >>> OvmfPkg\Library\LoadLinuxLib\X64\JumpToKernel.nasm and it used DB. >>>> Not sure if there is any BKM why they use it. >>>> >>>> Thanks, >>>> Guo >>>> >>>>> -----Original Message----- >>>>> From: Kinney, Michael D >>>>> Sent: Monday, January 4, 2021 9:31 PM >>>>> To: devel@edk2.groups.io; Dong, Guo ; Kinney, >>> Michael >>>>> D >>>>> Cc: Dong, Eric ; Ni, Ray ; >>>>> lersek@redhat.com; Kumar, Rahul1 >>>>> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error >>>>> >>>>> Hi Guo, >>>>> >>>>> NASM has good support for instructions. Can the DB be removed and >>> replaced >>>>> with the equivalent instruction? >>>>> >>>>> Thanks, >>>>> >>>>> Mike >>>>> >>>>>> -----Original Message----- >>>>>> From: devel@edk2.groups.io On Behalf Of Guo >>> Dong >>>>>> Sent: Thursday, December 24, 2020 12:04 PM >>>>>> To: devel@edk2.groups.io >>>>>> Cc: Dong, Eric ; Ni, Ray ; >>>>> lersek@redhat.com; Kumar, Rahul1 >>>>>> >>>>>> Subject: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error >>>>>> >>>>>> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3084 >>>>>> >>>>>> When DXE drivers are dispatched above 4GB memory in 64bit >>>>>> mode, the address setCodeSelectorLongJump in stack will >>>>>> be override by parameter. Jump to Qword is not supported >>>>>> by some processors. So use retfq instead. >>>>>> >>>>>> Signed-off-by: Guo Dong >>>>>> --- >>>>>> UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm | 8 +++----- >>>>>> 1 file changed, 3 insertions(+), 5 deletions(-) >>>>>> >>>>>> diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm >>>>> b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm >>>>>> index c3489bcc3e..e33ddb2784 100644 >>>>>> --- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm >>>>>> +++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm >>>>>> @@ -20,13 +20,11 @@ >>>>>> ;------------------------------------------------------------------------------ >>>>>> global ASM_PFX(SetCodeSelector) >>>>>> ASM_PFX(SetCodeSelector): >>>>>> - sub rsp, 0x10 >>>>>> + push rcx, >>>>>> lea rax, [setCodeSelectorLongJump] >>>>>> - mov [rsp], rax >>>>>> - mov [rsp+4], cx >>>>>> - jmp dword far [rsp] >>>>>> + push rax >>>>>> + DB 0x48, 0xcb ; retfq >>>>>> setCodeSelectorLongJump: >>>>>> - add rsp, 0x10 >>>>>> ret >>>>>> >>>>>> ;------------------------------------------------------------------------------ >>>>>> -- >>>>>> 2.16.2.windows.1 >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >