El Thu, Jun 08, 2017 at 07:18:36PM +0000 Ard Biesheuvel ha dit: > On 8 June 2017 at 19:08, Matthias Kaehlcke <mka@xxxxxxxxxxxx> wrote: > > El Thu, May 18, 2017 at 10:09:53AM +0100 Ard Biesheuvel ha dit: > > > >> Clang may emit absolute symbol references when building in non-PIC mode, > >> even when using the default 'small' code model, which is already mostly > >> position independent to begin with, due to its use of adrp/add pairs > >> that have a relative range of +/- 4 GB. The remedy is to pass the -fpie > >> flag, which can be done safely now that the code has been updated to avoid > >> GOT indirections (which may be emitted due to the compiler assuming that > >> the PIC/PIE code may end up in a shared library that is subject to ELF > >> symbol preemption) > >> > >> Passing -fpie when building code that needs to execute at an a priori > >> unknown offset is arguably an improvement in any case, and given that > >> the recent visibility changes allow the PIC build to pass with GCC as > >> well, let's add -fpie for all arm64 builds rather than only for Clang. > >> > >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > > > > Tested-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> > > Thanks Matthias. > > For the record, did you test only with Clang? With both gcc and clang. Booting has only been tested with an older kernel (v3.18), I suppose it shouldn't make a difference. -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
