On Mon, Nov 05, 2018 at 10:10:22AM -0500, Rich Felker wrote: > On Mon, Nov 05, 2018 at 11:13:53AM +0000, Szabolcs Nagy wrote: > > On 04/11/18 09:05, Stafford Horne wrote: > > > On Mon, Oct 29, 2018 at 02:28:11PM +0000, Szabolcs Nagy wrote: > > >> On 27/10/18 05:37, Stafford Horne wrote: > > ... > > >>> +#undef LINK_SPEC > > >>> +#define LINK_SPEC "%{h*} \ > > >>> + %{static:-Bstatic} \ > > >>> + %{shared:-shared} \ > > >>> + %{symbolic:-Bsymbolic} \ > > >>> + %{!static: \ > > >>> + %{rdynamic:-export-dynamic} \ > > >>> + %{!shared:-dynamic-linker " GNU_USER_DYNAMIC_LINKER "}}" > > >>> + > > >>> +#endif /* GCC_OR1K_LINUX_H */ > > >> > > >> note that because of the -static-pie mess each > > >> target needs a more complicated LINK_SPEC now. > > > > > > Hello, > > > > > > Does something like this look better? > > > > > > --- a/gcc/config/or1k/linux.h > > > +++ b/gcc/config/or1k/linux.h > > > @@ -37,8 +37,9 @@ > > > %{static:-Bstatic} \ > > > %{shared:-shared} \ > > > %{symbolic:-Bsymbolic} \ > > > - %{!static: \ > > > + %{!static:%{!static-pie: \ > > > %{rdynamic:-export-dynamic} \ > > > - %{!shared:-dynamic-linker " GNU_USER_DYNAMIC_LINKER "}}" > > > + %{!shared:-dynamic-linker " GNU_USER_DYNAMIC_LINKER "}}} \ > > > + %{static-pie:-Bstatic -pie --no-dynamic-linker -z text}" > > > > > > #endif /* GCC_OR1K_LINUX_H */ > > > > looks ok. > > > > > I have tested this out with or1k-linux-musl, but I get some LD complaints > > > i.e. > > > > > > .../or1k-linux-musl/bin/ld: .../or1k-linux-musl/lib/libc.a(exit.o): > > > non-pic relocation against symbol __fini_array_end > > > .../or1k-linux-musl/bin/ld: .../or1k-linux-musl/lib/libc.a(exit.o): > > > non-pic relocation against symbol __fini_array_start > > > > > > Those are some warnings we recently added to LD, perhaps I need to > > > rebuild the > > > libc.a with PIE as well. I will try it out, but if anyone has some > > > suggestions > > > that would be helpful. > > > > yes, musl does not build libc.a with pic by default, > > either use a gcc configured with --enable-default-pie > > or CC='gcc -fPIC' when building musl. > > > > after that -static-pie linking should work. > > > > (maybe musl should have an --enable-static-pie config > > option to make this simpler) > > For practical purposes, if you want to use static pie, you need a > default-pie toolchain. This is because _every_ static lib you might > link needs to be built with -fPIE (or -fPIC), and ensuring that > happens on a package-by-package basis is largely impractical; at least > it's on the same order of magnitude of difficulty as other systems > integration/packaging tasks.
Thanks, I kind of figured it out, but it was no so clear when I started. > However from the musl side it might make sense to produce a libc_pic.a > as part of the build process. This would make it easy to replace > libc.a with libc_pic.a if desired, and could also be used as the basis > for linking libc.so and to allow production of a stripped-down libc.so > that only includes symbols a fixed set of binaries depend on. We could > discuss something like this on the musl list. That makes sense. Thanks Rich for your input. -Stafford