From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 9C6FE22364882 for ; Tue, 30 Jan 2018 10:11:39 -0800 (PST) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9ADEC68560; Tue, 30 Jan 2018 18:17:13 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-120-185.rdu2.redhat.com [10.10.120.185]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1B6C55FCC1; Tue, 30 Jan 2018 18:17:08 +0000 (UTC) To: "Kinney, Michael D" , edk2-devel-01 Cc: "Ni, Ruiyu" , "Yao, Jiewen" , "Dong, Eric" , Paolo Bonzini References: <20180130153348.31992-1-lersek@redhat.com> <20180130153348.31992-2-lersek@redhat.com> From: Laszlo Ersek Message-ID: <31138ce7-0637-a755-ec57-e36ab812f259@redhat.com> Date: Tue, 30 Jan 2018 19:17:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 30 Jan 2018 18:17:13 +0000 (UTC) Subject: Re: [PATCH 1/3] UefiCpuPkg/PiSmmCpuDxeSmm: update comments in IA32 SmmStartup() X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Jan 2018 18:11:40 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 01/30/18 18:22, Kinney, Michael D wrote: > Laszlo, > > The DBs can be removed if the label is moved after > the instruction and the patch is done to the label > minus the size of the patch value. Indeed I haven't thought of this. If I understand correctly, it means extern UINT8 gSmmCr0; *(UINT32*)(&gSmmCr0 - sizeof (UINT32)) = (UINT32)AsmReadCr0 (); TBH, the DB feels less ugly to me than this :) Still, if you think it would be an acceptable price to pay for removing the remaining DBs, I can respin. Thanks Laszlo >> -----Original Message----- >> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] >> On Behalf Of Laszlo Ersek >> Sent: Tuesday, January 30, 2018 7:34 AM >> To: edk2-devel-01 >> Cc: Ni, Ruiyu ; Yao, Jiewen >> ; Dong, Eric ; >> Paolo Bonzini >> Subject: [edk2] [PATCH 1/3] UefiCpuPkg/PiSmmCpuDxeSmm: >> update comments in IA32 SmmStartup() >> >> The gSmmCr3, gSmmCr4, gSmmCr0 and gSmmJmpAddr global >> variables are used >> for patching assembly instructions, thus we can never >> remove the DB >> encodings for those instructions. At least we should add >> the intended >> meanings in comments. >> >> This patch only changes comments. >> >> Cc: Eric Dong >> Cc: Jian J Wang >> Cc: Jiewen Yao >> Cc: Paolo Bonzini >> Cc: Ruiyu Ni >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Laszlo Ersek >> --- >> UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm >> b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm >> index e96dd8d2392a..08534dba64b7 100644 >> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm >> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm >> @@ -44,34 +44,34 @@ global ASM_PFX(SmmStartup) >> ASM_PFX(SmmStartup): >> DB 0x66 >> mov eax, 0x80000001 ; read >> capability >> cpuid >> DB 0x66 >> mov ebx, edx ; rdmsr will >> change edx. keep it in ebx. >> - DB 0x66, 0xb8 >> + DB 0x66, 0xb8 ; mov eax, imm32 >> ASM_PFX(gSmmCr3): DD 0 >> mov cr3, eax >> DB 0x67, 0x66 >> lgdt [cs:ebp + (ASM_PFX(gcSmiInitGdtr) - >> ASM_PFX(SmmStartup))] >> - DB 0x66, 0xb8 >> + DB 0x66, 0xb8 ; mov eax, imm32 >> ASM_PFX(gSmmCr4): DD 0 >> mov cr4, eax >> DB 0x66 >> mov ecx, 0xc0000080 ; IA32_EFER MSR >> rdmsr >> DB 0x66 >> test ebx, BIT20 ; check NXE >> capability >> jz .1 >> or ah, BIT3 ; set NXE bit >> wrmsr >> .1: >> - DB 0x66, 0xb8 >> + DB 0x66, 0xb8 ; mov eax, imm32 >> ASM_PFX(gSmmCr0): DD 0 >> DB 0xbf, PROTECT_MODE_DS, 0 ; mov di, >> PROTECT_MODE_DS >> mov cr0, eax >> - DB 0x66, 0xea ; jmp far >> [ptr48] >> + DB 0x66, 0xea ; jmp far >> [ptr48] >> ASM_PFX(gSmmJmpAddr): >> DD @32bit >> DW PROTECT_MODE_CS >> @32bit: >> mov ds, edi >> mov es, edi >> -- >> 2.14.1.3.gb7cf6e02401b >> >> >> _______________________________________________ >> edk2-devel mailing list >> edk2-devel@lists.01.org >> https://lists.01.org/mailman/listinfo/edk2-devel