From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.100; helo=mga07.intel.com; envelope-from=ruiyu.ni@intel.com; receiver=edk2-devel@lists.01.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (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 6FEDA2222C229 for ; Tue, 30 Jan 2018 21:39:22 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Jan 2018 21:44:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,438,1511856000"; d="scan'208";a="13888153" Received: from ray-dev.ccr.corp.intel.com (HELO [10.239.9.19]) ([10.239.9.19]) by orsmga007.jf.intel.com with ESMTP; 30 Jan 2018 21:44:55 -0800 To: "Kinney, Michael D" , Laszlo Ersek , edk2-devel-01 Cc: Paolo Bonzini , "Yao, Jiewen" , "Dong, Eric" References: <20180130153348.31992-1-lersek@redhat.com> <20180130153348.31992-2-lersek@redhat.com> <31138ce7-0637-a755-ec57-e36ab812f259@redhat.com> <17c44add-ca8e-c346-8cc8-7e94b694a7e1@redhat.com> From: "Ni, Ruiyu" Message-ID: <3932fc60-2a38-261f-183c-fd686643d684@Intel.com> Date: Wed, 31 Jan 2018 13:44:55 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: 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: Wed, 31 Jan 2018 05:39:23 -0000 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Mike, Laszlo, Does the patch only apply to the operand? If so, PatchAssembly looks too general. How about the name like PatchAssemblyOperand? On 1/31/2018 6:25 AM, Kinney, Michael D wrote: > Laszlo, > > I agree that the function is better than a macro. > > I thought of the alignment issues as well. CopyMem() > is a good solution. We could also consider > WriteUnalignedxx() functions in BaseLib. > > I was originally thinking this functionality would go > into BaseLib. But with the use of CopyMem(), we can't > do that. Maybe we should use WriteUnalignedxx() and > add some ASSERT() checks. > > VOID > PatchAssembly ( > VOID *BufferEnd, > UINT64 PatchValue, > UINTN ValueSize > ) > { > ASSERT ((UINTN)BufferEnd > ValueSize); > switch (ValueSize) { > case 1: > ASSERT (PatchValue <= MAX_UINT8); > *((UINT8 *)BufferEnd - 1) = (UINT8)PatchValue; > case 2: > ASSERT (PatchValue <= MAX_UINT16); > WriteUnaligned16 ((UINT16 *)(BufferEnd) - 1, (UINT16)PatchValue)); > break; > case 4: > ASSERT (PatchValue <= MAX_UINT32); > WriteUnaligned32 ((UINT32 *)(BufferEnd) - 1, (UINT32)PatchValue)); > break; > case 8: > WriteUnaligned64 ((UINT64 *)(BufferEnd) - 1, PatchValue)); > break; > default: > ASSERT (FALSE); > } > } > > Mike > >> -----Original Message----- >> From: Laszlo Ersek [mailto:lersek@redhat.com] >> Sent: Tuesday, January 30, 2018 1:45 PM >> To: Kinney, Michael D ; edk2- >> devel-01 >> Cc: Ni, Ruiyu ; Paolo Bonzini >> ; Yao, Jiewen >> ; Dong, Eric >> Subject: Re: [edk2] [PATCH 1/3] >> UefiCpuPkg/PiSmmCpuDxeSmm: update comments in IA32 >> SmmStartup() >> >> On 01/30/18 21:31, Kinney, Michael D wrote: >>> Laszlo, >>> >>> We have already used this technique in other NASM files >>> to remove DBs. >> >> OK. >> >>> Let us know if you have suggestions on how to make the >>> C code that performs the patches easier to read and >>> maintain. >> >> How about this: >> >> VOID >> PatchAssembly ( >> VOID *BufferEnd, >> UINT64 PatchValue, >> UINTN ValueSize >> ) >> { >> CopyMem ( >> (VOID *)((UINTN)BufferEnd - ValueSize), >> &PatchValue, >> ValueSize >> ); >> } >> >> extern UINT8 gAsmSmmCr0; >> extern UINT8 gAsmSmmCr3; >> extern UINT8 gAsmSmmCr4; >> >> ... >> { >> PatchAssembly (&gAsmSmmCr0, AsmReadCr0 (), 4); >> PatchAssembly (&gAsmSmmCr3, AsmReadCr3 (), 4); >> PatchAssembly (&gAsmSmmCr4, AsmReadCr4 (), 4); >> ... >> } >> >> (I think it's fine to open-code the last argument as "4", >> rather than >> "sizeof (UINT32)", because for patching, we must have >> intimate knowledge >> of the instruction anyway.) >> >> To me, this is easier to read, because: >> >> - there are no complex casts in the "business logic" >> - the size is spelled out once per patching >> - the function name and the variable names make it clear >> we are patching >> separately compiled assembly code that was linked into >> the same >> module. >> >> What do you think? >> >> Thanks! >> Laszlo >> >>>> -----Original Message----- >>>> From: edk2-devel [mailto:edk2-devel- >> bounces@lists.01.org] >>>> On Behalf Of Laszlo Ersek >>>> Sent: Tuesday, January 30, 2018 10:17 AM >>>> To: Kinney, Michael D ; >> edk2- >>>> devel-01 >>>> Cc: Ni, Ruiyu ; Paolo Bonzini >>>> ; Yao, Jiewen >>>> ; Dong, Eric >> >>>> Subject: Re: [edk2] [PATCH 1/3] >>>> UefiCpuPkg/PiSmmCpuDxeSmm: update comments in IA32 >>>> SmmStartup() >>>> >>>> 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 >>>> >>>> _______________________________________________ >>>> edk2-devel mailing list >>>> edk2-devel@lists.01.org >>>> https://lists.01.org/mailman/listinfo/edk2-devel > -- Thanks, Ray