On Thursday 04 December 2014 15:48:50 Olof Johansson wrote: > On Thu, Dec 4, 2014 at 3:41 PM, Alexander Graf <ag...@suse.de> wrote: > > On 04.12.14 22:15, Olof Johansson wrote: > >> On Thu, Dec 4, 2014 at 7:46 AM, Alexander Graf <ag...@suse.de> wrote: > >>> With binutils 2.25 the default alignment for 32bit arm sections changed to > >>> have everything 64k aligned. Armv7 binaries built with this binutils > >>> version > >>> run successfully on an arm64 system. > >>> > >>> Since effectively there is now the chance to run armv7 code on arm64 even > >>> with 64k page size, it doesn't make sense to block people from enabling > >>> CONFIG_COMPAT on those configurations. > >>> > >>> Signed-off-by: Alexander Graf <ag...@suse.de> > >>> --- > >>> arch/arm64/Kconfig | 1 - > >>> 1 file changed, 1 deletion(-) > >>> > >>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > >>> index 9532f8d..3cf4f238 100644 > >>> --- a/arch/arm64/Kconfig > >>> +++ b/arch/arm64/Kconfig > >>> @@ -409,7 +409,6 @@ source "fs/Kconfig.binfmt" > >>> > >>> config COMPAT > >>> bool "Kernel support for 32-bit EL0" > >>> - depends on !ARM64_64K_PAGES > >>> select COMPAT_BINFMT_ELF > >>> select HAVE_UID16 > >>> select OLD_SIGSUSPEND3 > >> > >> This is hardly "compat". Sure, it's great to have a new binutils that > >> has larger alignment, but practically not a single existing binary > >> will work today if someone tries to do this. > > > > Yes, but IMHO that's an implementation detail. The same applies for > > 32bit PPC binaries if you use 4k aligned segments. If your applications > > are not aligned for your page size, you can't run them. The only > > platform that managed nevertheless FWIW was IA64 ;). > > Yes, but there the binutils change happened early enough that by the > time the kernel change went in, all major distros had binaries that > were compatible.
What is the exact symptom you see when running an unaligned user space binary on 64k-pages? Do we at least print a helpful error message somewhere or does it just crash? Should we add support for 64k-pages in the arm32 kernel as well now? Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/