Re: [Patch] BaseTools: Add the missing -pie link option in GCC tool chain

["Gao, Liming" <liming.gao@intel.com>]

Laszlo:
  Thanks for your quick test. I will add Bugzilla in commit log. And, I will let you know once I push this patch. 

Thanks
Liming
> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, August 23, 2017 6:27 PM
> To: Gao, Liming <liming.gao@intel.com>
> Cc: edk2-devel@lists.01.org; Shi, Steven <steven.shi@intel.com>; Paolo Bonzini <pbonzini@redhat.com>; Ard Biesheuvel
> <ard.biesheuvel@linaro.org>; Justen, Jordan L <jordan.l.justen@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>
> Subject: Re: [edk2] [Patch] BaseTools: Add the missing -pie link option in GCC tool chain
> 
> Hi Liming,
> 
> On 08/23/17 10:04, Liming Gao wrote:
> > GCC tool chain uses -fpie in CC_FLAGS. So, add -pie in DLINK_FLAGS.
> >
> > More discussion in
> > https://lists.01.org/pipermail/edk2-devel/2017-August/013508.html
> >
> > 3.13 Options for Linking
> > ========================
> > '-pie'
> >      Produce a position independent executable on targets that support
> >      it.  For predictable results, you must also specify the same set
> >      of options used for compilation ('-fpie', '-fPIE', or model
> >      suboptions) when you specify this linker option.
> >
> > 3.18 Options for Code Generation Conventions
> > ============================================
> > '-fpie'
> > '-fPIE'
> >      These options are similar to '-fpic' and '-fPIC', but generated
> >      position independent code can be only linked into executables.
> >      Usually these options are used when '-pie' GCC option is used
> >      during linking.
> >      '-fpie' and '-fPIE' both define the macros '__pie__' and
> >      '__PIE__'. The macros have the value 1 for '-fpie' and 2 for
> >      '-fPIE'.
> >
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Liming Gao <liming.gao@intel.com>
> > ---
> >  BaseTools/Conf/tools_def.template | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template
> > index 6076a69..aff0cbd 100755
> > --- a/BaseTools/Conf/tools_def.template
> > +++ b/BaseTools/Conf/tools_def.template
> > @@ -4502,7 +4502,7 @@ DEFINE GCC44_IA32_X64_DLINK_COMMON   = -nostdlib -Wl,-n,-q,--gc-sections -z comm
> >  DEFINE GCC44_IA32_X64_ASLDLINK_FLAGS = DEF(GCC44_IA32_X64_DLINK_COMMON) -Wl,--entry,ReferenceAcpiTable -u
> ReferenceAcpiTable
> >  DEFINE GCC44_IA32_X64_DLINK_FLAGS    = DEF(GCC44_IA32_X64_DLINK_COMMON) -Wl,--entry,$(IMAGE_ENTRY_POINT) -u
> $(IMAGE_ENTRY_POINT) -Wl,-Map,$(DEST_DIR_DEBUG)/$(BASE_NAME).map
> >  DEFINE GCC44_IA32_DLINK2_FLAGS       = -Wl,--defsym=PECOFF_HEADER_SIZE=0x220 DEF(GCC_DLINK2_FLAGS_COMMON)
> > -DEFINE GCC44_X64_DLINK_FLAGS         = DEF(GCC44_IA32_X64_DLINK_FLAGS) -Wl,-melf_x86_64,--oformat=elf64-x86-64
> > +DEFINE GCC44_X64_DLINK_FLAGS         = DEF(GCC44_IA32_X64_DLINK_FLAGS)
> -Wl,-melf_x86_64,--oformat=elf64-x86-64,-pie
> >  DEFINE GCC44_X64_DLINK2_FLAGS        = -Wl,--defsym=PECOFF_HEADER_SIZE=0x228 DEF(GCC_DLINK2_FLAGS_COMMON)
> >  DEFINE GCC44_ASM_FLAGS               = DEF(GCC_ASM_FLAGS)
> >
> > @@ -4582,7 +4582,7 @@ DEFINE GCC49_IA32_X64_DLINK_COMMON   = -nostdlib -Wl,-n,-q,--gc-sections -z comm
> >  DEFINE GCC49_IA32_X64_ASLDLINK_FLAGS = DEF(GCC49_IA32_X64_DLINK_COMMON) -Wl,--entry,ReferenceAcpiTable -u
> ReferenceAcpiTable
> >  DEFINE GCC49_IA32_X64_DLINK_FLAGS    = DEF(GCC49_IA32_X64_DLINK_COMMON) -Wl,--entry,$(IMAGE_ENTRY_POINT) -u
> $(IMAGE_ENTRY_POINT) -Wl,-Map,$(DEST_DIR_DEBUG)/$(BASE_NAME).map
> >  DEFINE GCC49_IA32_DLINK2_FLAGS       = DEF(GCC48_IA32_DLINK2_FLAGS)
> > -DEFINE GCC49_X64_DLINK_FLAGS         = DEF(GCC49_IA32_X64_DLINK_FLAGS) -Wl,-melf_x86_64,--oformat=elf64-x86-64
> > +DEFINE GCC49_X64_DLINK_FLAGS         = DEF(GCC49_IA32_X64_DLINK_FLAGS)
> -Wl,-melf_x86_64,--oformat=elf64-x86-64,-pie
> >  DEFINE GCC49_X64_DLINK2_FLAGS        = DEF(GCC48_X64_DLINK2_FLAGS)
> >  DEFINE GCC49_ASM_FLAGS               = DEF(GCC48_ASM_FLAGS)
> >  DEFINE GCC49_ARM_ASM_FLAGS           = DEF(GCC48_ARM_ASM_FLAGS)
> >
> 
> (1) you forgot to CC the participants of the previous thread :)
> 
> (2) Please add a reference to
> <https://bugzilla.tianocore.org/show_bug.cgi?id=671> to the commit message.
> 
> (3) I tested the GCC49_X64_DLINK_FLAGS change with the following
> commands, on Fedora 26 (the gcc version is "7.1.1 20170622 (Red Hat
> 7.1.1-3)"):
> 
> $ git clean -fdx
> $ git reset --hard
> $ . edksetup.sh --reconfig
> $ make -C "$EDK_TOOLS_PATH"
> $ build -a X64 -p OvmfPkg/OvmfPkgX64.dsc -t GCC5 -n 6 -b DEBUG
> $ qemu-system-x86_64 \
>     -m 5120 \
>     -smp 8 \
>     -pflash Build/OvmfX64/DEBUG_GCC5/FV/OVMF.fd \
>     -enable-kvm \
>     -global isa-debugcon.iobase=0x402 \
>     -debugcon file:debug-gcc5-64.fd.log \
>     -net none
> 
> The resultant OVMF binary works fine. (The UEFI shell is reached OK.)
> 
> (4) I regression-tested the GCC44_X64_DLINK_FLAGS change on RHEL-7.4,
> using "gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-16)". No regressions were
> found.
> 
> Tested-by: Laszlo Ersek <lersek@redhat.com>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> 
> (5) When you push the patch (possibly after receiving comments from
> others), please send a reminder for me to revert commit ca56256d5e0b
> ("OvmfPkg/build.sh: select the GCC49 toolchain settings for gcc-7.*",
> 2017-08-15).
> 
> Thanks!
> Laszlo