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-boun...@lists.01.org] >> On Behalf Of Laszlo Ersek >> Sent: Tuesday, January 30, 2018 7:34 AM >> To: edk2-devel-01 <edk2-devel@lists.01.org> >> Cc: Ni, Ruiyu <ruiyu...@intel.com>; Yao, Jiewen >> <jiewen....@intel.com>; Dong, Eric <eric.d...@intel.com>; >> Paolo Bonzini <pbonz...@redhat.com> >> 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 <eric.d...@intel.com> >> Cc: Jian J Wang <jian.j.w...@intel.com> >> Cc: Jiewen Yao <jiewen....@intel.com> >> Cc: Paolo Bonzini <pbonz...@redhat.com> >> Cc: Ruiyu Ni <ruiyu...@intel.com> >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Laszlo Ersek <ler...@redhat.com> >> --- >> 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
