Hello Waldemar, Le 21/05/2021 à 10:34, Waldemar Brodkorb a écrit : > Hi Romain, > > can you confirm that attached patch works for you? > I tested with non-PIE and PIE and both seems to work.
Thanks for your feedback. Indeed, removing the code enabled by HAVE_ASM_PPC_REL16 allow to boot the system (We could also remove entirely the PPC_HAS_REL16 test from Rules.mak) but I would keep this code instead (based on Glibc code history analysis). Yann Sionneau seems to have an interesting findings. Best regards, Romain > > best regards > Waldemar > > Romain Naour wrote, > >> 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
