Hi, This is not about UefiPayload. I did not have GCC5 in my environment, so I use a newer GCC to compile. However, in newer gcc (let's say GCC8), it generates floating point instructions in each function and system will crash as you mentioned that we did not handle it in UEFI. I uploaded this patch because many people from our group use newer GCC and it will be more convenient if we can disable it with a flag (otherwise, we need to maintain a local patch). I guess the real fix (bigger work) is for EDK2 to support the newer GCC version in its toolchain (create something like *_GCC8_*). Back to the question, I think it should be no harm to add these flags to tool_defs.txt if EDK2 did not expect the compiler to generate MMX/SSE instructions in the first place. -- Cheng-Chieh On Sat, Jul 24, 2021 at 12:46 AM Kinney, Michael D < michael.d.kinney@intel.com> wrote: > Can you provide details on why this flag was needed in the UefiPayloadPkg > use case? > > > > If the newer versions of the GCC compilers are injecting use of MMX/SSE > instructions from optimization of C code, then we need to unconditionally > disable that usage in tools_def.txt. The only place MMX/SSE instructions > can be used is in NASM files with proper save/restore of the MMX/SSE state. > > > > Here is an example with use of xmm0 that is saved/restored on the stack. > > > > > https://github.com/tianocore/edk2/blob/master/MdePkg/Library/BaseMemoryLibSse2/X64/CopyMem.nasm > > > > Mike > > > > *From:* Cheng-Chieh Huang > *Sent:* Friday, July 23, 2021 4:17 AM > *To:* gaoliming > *Cc:* devel@edk2.groups.io; Kinney, Michael D > *Subject:* Re: [edk2-devel] [PATCH v1 5/6] UefiPayloadPkg: Add > DISABLE_MMX_SSE to avoid generating floating points operation > > > > I got what you mean by "Tools_def.txt doesn’t support build flag" now. I > thought the parser does support some sort of if/else condition, but it > seems to be not the case. Alternatively, we can do this during the copy > (from template to tools_def.txt), but everytime we need to recreate > tools_def.txt which is not ideal). > > > > In that case, I think we should just roll back to only doing this in > UefiPayloadPkg.dsc. If other packs want to add these flags, they will need > to do it on their own. > > > > On Fri, Jul 23, 2021 at 6:29 PM gaoliming > wrote: > > How do you add this support in tools_def? Can you give the proposal for it? > > > > Thanks > > Liming > > *发件人**:* Cheng-Chieh Huang > *发送时间:* 2021年7月22日 10:35 > *收件人:* gaoliming > *抄送:* devel@edk2.groups.io; Kinney, Michael D > *主题:* Re: [edk2-devel] [PATCH v1 5/6] UefiPayloadPkg: Add DISABLE_MMX_SSE > to avoid generating floating points operation > > > > I mean, I will submit a patch to support DISABLE_GCC_MMX_SSE in tools_def. > What do you think? > > > > -- > > Cheng-Chieh > > > > On Thu, Jul 22, 2021 at 9:28 AM gaoliming > wrote: > > Tools_def.txt doesn’t support build flag DISABLE_GCC_MMX_SSE. If this > flag is moved into BaseTools\Conf\tools_def.template, -mno-mmx -mno-sse > option will be the default GCC options. That means all platforms will apply > them. > > > > Thanks > > Liming > > *发件人**:* devel@edk2.groups.io *代表 *Cheng-Chieh > Huang via groups.io > *发送时间:* 2021年7月22日 1:43 > *收件人:* Kinney, Michael D > *抄送:* devel@edk2.groups.io > *主题:* Re: [edk2-devel] [PATCH v1 5/6] UefiPayloadPkg: Add DISABLE_MMX_SSE > to avoid generating floating points operation > > > > Yes, we can. I will drop this patch for this uefipayload batch and send > another one for support DISABLE_GCC_MMX_SSE in tools_de.txt. > > > > -- > > Cheng-Chieh > > On Thu, Jul 22, 2021, 12:35 AM Kinney, Michael D < > michael.d.kinney@intel.com> wrote: > > Are those flags needed for all packages that build with GCC? > > Should this be moved into tools_def.txt? > > Mike > > > -----Original Message----- > > From: devel@edk2.groups.io On Behalf Of > Cheng-Chieh Huang via groups.io > > Sent: Wednesday, July 21, 2021 6:23 AM > > To: devel@edk2.groups.io > > Cc: Cheng-Chieh Huang > > Subject: [edk2-devel] [PATCH v1 5/6] UefiPayloadPkg: Add DISABLE_MMX_SSE > to avoid generating floating points operation > > > > This will allow we compile payload using gcc8 > > > > Signed-off-by: Cheng-Chieh Huang > > --- > > UefiPayloadPkg/UefiPayloadPkg.dsc | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/UefiPayloadPkg/UefiPayloadPkg.dsc > b/UefiPayloadPkg/UefiPayloadPkg.dsc > > index 8aa5f18cd35c..fa41c5a24af5 100644 > > --- a/UefiPayloadPkg/UefiPayloadPkg.dsc > > +++ b/UefiPayloadPkg/UefiPayloadPkg.dsc > > @@ -30,6 +30,8 @@ [Defines] > > DEFINE PS2_KEYBOARD_ENABLE = FALSE > > DEFINE UNIVERSAL_PAYLOAD = FALSE > > > > + DEFINE DISABLE_MMX_SSE = FALSE > > + > > # > > # SBL: UEFI payload for Slim Bootloader > > # COREBOOT: UEFI payload for coreboot > > @@ -96,6 +98,9 @@ [BuildOptions] > > *_*_*_CC_FLAGS = -D DISABLE_NEW_DEPRECATED_INTERFACES > > !if $(BOOTLOADER) == "LINUXBOOT" > > *_*_*_CC_FLAGS = -D LINUXBOOT_PAYLOAD > > +!endif > > +!if $(DISABLE_MMX_SSE) > > + *_*_*_CC_FLAGS = -mno-mmx -mno-sse > > !endif > > GCC:*_UNIXGCC_*_CC_FLAGS = -DMDEPKG_NDEBUG > > GCC:RELEASE_*_*_CC_FLAGS = -DMDEPKG_NDEBUG > > -- > > 2.32.0.402.g57bb445576-goog > > > > > > > > > > > > > >