Hi Waldemar, Le 19/05/2021 à 00:09, Waldemar Brodkorb a écrit : > Hi Romain, > Romain Naour wrote, > >> Hello, >> >> Recently in Buildroot the option BR2_PIC_PIE has been enabled by default >> along >> with other hardening features [1]. Since then some ppc defconfig such >> qemu_ppc_e500mc_defconfig are failing to boot due to a segfault in init >> program. >> >> The segfault appear very early in __uClibc_main while starting any binaries, >> an issue located in crt1.S (powerpc)[2]. >> >> After some trial and error, removing HAVE_ASM_PPC_REL16 from CFLAGS [3] >> allow to generate a working system again. But this is actually wrong since >> instead we should consider HAVE_ASM_PPC_REL16 always true nowadays. > > What if the assembly inside HAVE_ASM_PPC_REL16 isn't pie safe?
Good question. I guess it should work with pie (see PIEFLAG_NAME:=-fpie) https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/Rules.mak?h=v1.0.38#n480 I did a try with Glibc without any problem with BR2_PIC_PIE enabled. Best regards, Romain > >> Indeed, Glibc removed HAVE_ASM_PPC_REL16 since version 2.22 [4] since "the >> minimum binutils supports rel16 relocs". Binutils 2.22 supports R_PPC_REL16 >> as >> default. >> >> uClibc-ng should remove HAVE_ASM_PPC_REL16 but keep the code as it was >> defined. >> But this doesn't fix the initial issue. >> >> Any idea ? >> >> [1] >> https://git.buildroot.net/buildroot/commit/?id=810ba387bec3c5b6904e8893fb4cb6f9d3717466 >> [2] >> https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/powerpc/crt1.S?id=2bf4991c4dd7b50b74656011dea9c40464ff390c#n47 >> [3] >> https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/Rules.mak?id=2bf4991c4dd7b50b74656011dea9c40464ff390c#n486 >> [4] >> https://sourceware.org/git/?p=glibc.git;a=commit;h=59261ad3eb345e0d7b9f5c73e1a09d046991cea5 > > best regards > Waldemar > _______________________________________________ devel mailing list devel@uclibc-ng.org https://mailman.uclibc-ng.org/cgi-bin/mailman/listinfo/devel
