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d6efcc118e
The PowerPC64 linker edits medium model toc-indirect code to toc-pointer relative: addis r9,r2,tc_entry_for_var@toc@ha ld r9,tc_entry_for_var@toc@l(r9) becomes addis r9,r2,(var-.TOC.)@ha addi r9,r9,(var-.TOC.)@l when "var" is known to be local to the binary. This isn't done for small-model toc-indirect code, because "var" is almost guaranteed to be too far away from .TOC. for a 16-bit signed offset. And, because the analysis of which .toc entry can be removed becomes much more complicated in objects that mix code models, they aren't removed if any small-model toc sequence appears in an object file. Unfortunately, glibc's build of ld.so smashes the needed objects together in a ld -r linking stage. This means the GOT/TOC is left with a whole lot of relative relocations which is untidy, but in itself is not a serious problem. However, static-pie on powerpc64 bombs due to a segfault caused by one of the small-model accesses before _dl_relocate_static_pie. (The very first one in rcrt1.o passing start_addresses in r8 to __libc_start_main.) So this patch makes all the toc/got accesses in assembly medium code model, and a couple of functions hidden. By itself this is not enough to give us working static-pie, but it is useful in isolation to enable better linker optimisation. There's a serious problem in libgcc too. libgcc ifuncs access the AT_HWCAP words stored in the tcb with an offset from the thread pointer (r13), but r13 isn't set at the time _dl_relocate_static_pie. A followup patch will fix that. Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com> |
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| .. | ||
| a2 | ||
| be | ||
| bits | ||
| cell | ||
| fpu | ||
| le | ||
| multiarch | ||
| power4 | ||
| power6 | ||
| power7 | ||
| power8 | ||
| __longjmp-common.S | ||
| __longjmp.S | ||
| addmul_1.S | ||
| atomic-machine.h | ||
| bsd-_setjmp.S | ||
| bsd-setjmp.S | ||
| configure | ||
| configure.ac | ||
| crti.S | ||
| crtn.S | ||
| dl-dtprocnum.h | ||
| dl-funcdesc.h | ||
| dl-irel.h | ||
| dl-machine.c | ||
| dl-machine.h | ||
| dl-trampoline.S | ||
| ffsll.c | ||
| hp-timing.h | ||
| Implies | ||
| lshift.S | ||
| Makefile | ||
| memcpy.S | ||
| memset.S | ||
| mul_1.S | ||
| ppc-mcount.S | ||
| rtld-memset.c | ||
| setjmp-bug21895.c | ||
| setjmp-common.S | ||
| setjmp.S | ||
| stackguard-macros.h | ||
| start.S | ||
| strchr.S | ||
| strcmp.S | ||
| strlen.S | ||
| strncmp.S | ||
| submul_1.S | ||
| sysdep.h | ||
| tst-audit.h | ||
| tst-setjmp-bug21895-static.c | ||
| tst-ucontext-ppc64-vscr.c | ||