Re: [PATCH 2/2] x86/purgatory: remove -nostdlib compiler flag

[Fangrui Song]

On 2021-11-08, Nick Desaulniers wrote:
> On Sun, Nov 7, 2021 at 8:27 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> > The -nostdlib option requests the compiler to not use the standard
> > system startup files or libraries when linking. It is effective only
> > when $(CC) is used as a linker driver.
>
> Is that right? ld.lld recognizes --nostdlib and has --help text for it.

GCC/Clang driver -nostdlib != ld.bfd/ld.lld -nostdlib.

ld.lld -nostdlib just ignores SEARCH_DIR in a linker script.
I think ld.bfd's -nostdlib is more complex than that which also has
something to do with its internal linker script location.
Anyway, getting of the obscure ld -nostdlib is a good idea.

> > $(LD) is directly used for linking purgatory.{ro,chk} here, hence
> > -nostdlib is unneeded.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > ---
> >
> >  arch/x86/purgatory/Makefile | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> > index 95ea17a9d20c..ae53d54d7959 100644
> > --- a/arch/x86/purgatory/Makefile
> > +++ b/arch/x86/purgatory/Makefile
> > @@ -16,7 +16,7 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS
> >
> >  # When linking purgatory.ro with -r unresolved symbols are not checked,
> >  # also link a purgatory.chk binary without -r to check for unresolved symbols.
> > -PURGATORY_LDFLAGS := -e purgatory_start -nostdlib -z nodefaultlib
> > +PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib
> >  LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS)
> >  LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS)
> >  targets += purgatory.ro purgatory.chk
> > --
> > 2.30.2
>
> --
> Thanks,
> ~Nick Desaulniers