From 64029e93683a266c38d19789e780f3748bd6a188 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Fri, 5 Oct 2018 11:40:54 +0930 Subject: Separate header PT_LOAD for -z separate-code This patch, along with previous patches in the series, supports putting the ELF file header and program headers in a PT_LOAD without sections. Logic governing whether headers a loaded has changed a little: The primary reason to include headers is now the presence of SIZEOF_HEADERS in a linker script. However, to support scripts that may have reserved space for headers by hand, we continue to add headers whenever the first section address is past the end of headers modulo page size. include/ * bfdlink.h (struct bfd_link_info): Add load_phdrs field. bfd/ * elf-nacl.c (nacl_modify_segment_map): Cope with header PT_LOAD lacking sections. * elf.c (_bfd_elf_map_sections_to_segments): Assume file and program headers are required when info->load_phdrs. Reorganize code handling program headers. Generate a mapping without sections just for file and program headers when -z separate-code would indicate they should be on a different page to the first section. ld/ * ldexp.c (fold_name ): Set link_info.load_phdrs. * testsuite/ld-elf/loadaddr1.d: Pass -z noseparate-code. * testsuite/ld-elf/loadaddr2.d: Likewise. * testsuite/ld-i386/vxworks2.sd: Adjust expected output. * testsuite/ld-powerpc/vxworks2.sd: Likewise. * testsuite/ld-elf/overlay.d: Remove spu xfail. * testsuite/ld-spu/ovl.lnk: Don't use SIZEOF_HEADERS. * testsuite/ld-tic6x/dsbt-be.ld: Likewise. * testsuite/ld-tic6x/dsbt-inrange.ld: Likewise. * testsuite/ld-tic6x/dsbt-overflow.ld: Likewise. * testsuite/ld-tic6x/dsbt.ld: Likewise. --- bfd/elf-nacl.c | 88 ++++++++++++++++++++++++++++++---------------------------- 1 file changed, 46 insertions(+), 42 deletions(-) (limited to 'bfd/elf-nacl.c') diff --git a/bfd/elf-nacl.c b/bfd/elf-nacl.c index 5f446b4..71b2ad8 100644 --- a/bfd/elf-nacl.c +++ b/bfd/elf-nacl.c @@ -70,8 +70,7 @@ nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info) const struct elf_backend_data *const bed = get_elf_backend_data (abfd); struct elf_segment_map **m = &elf_seg_map (abfd); struct elf_segment_map **first_load = NULL; - struct elf_segment_map **last_load = NULL; - bfd_boolean moved_headers = FALSE; + struct elf_segment_map **headers = NULL; int sizeof_headers; if (info != NULL && info->user_phdrs) @@ -170,56 +169,61 @@ nacl_modify_segment_map (bfd *abfd, struct bfd_link_info *info) } /* First, we're just finding the earliest PT_LOAD. - By the normal rules, this will be the lowest-addressed one. - We only have anything interesting to do if it's executable. */ - last_load = m; + By the normal rules, this will be the lowest-addressed one. */ if (first_load == NULL) - { - if (!executable) - goto next; - first_load = m; - } + first_load = m; + /* Now that we've noted the first PT_LOAD, we're looking for the first non-executable PT_LOAD with a nonempty p_filesz. */ - else if (!moved_headers + else if (headers == NULL && segment_eligible_for_headers (seg, bed->minpagesize, sizeof_headers)) - { - /* This is the one we were looking for! - - First, clear the flags on previous segments that - say they include the file header and phdrs. */ - struct elf_segment_map *prevseg; - for (prevseg = *first_load; - prevseg != seg; - prevseg = prevseg->next) - if (prevseg->p_type == PT_LOAD) - { - prevseg->includes_filehdr = 0; - prevseg->includes_phdrs = 0; - } - - /* This segment will include those headers instead. */ - seg->includes_filehdr = 1; - seg->includes_phdrs = 1; - - moved_headers = TRUE; - } + headers = m; } - - next: m = &seg->next; } - if (first_load != last_load && moved_headers) + if (headers != NULL) { - /* Now swap the first and last PT_LOAD segments' - positions in segment_map. */ - struct elf_segment_map *first = *first_load; - struct elf_segment_map *last = *last_load; - *first_load = first->next; - first->next = last->next; - last->next = first; + struct elf_segment_map **last_load = NULL; + struct elf_segment_map *seg; + + m = first_load; + while ((seg = *m) != NULL) + { + if (seg->p_type == PT_LOAD) + { + /* Clear the flags on any previous segment that + included the file header and phdrs. */ + seg->includes_filehdr = 0; + seg->includes_phdrs = 0; + /* Also strip out empty segments. */ + if (seg->count == 0) + { + if (headers == &seg->next) + headers = m; + *m = seg->next; + continue; + } + last_load = m; + } + m = &seg->next; + } + + /* This segment will include those headers instead. */ + seg = *headers; + seg->includes_filehdr = 1; + seg->includes_phdrs = 1; + + if (last_load != NULL && first_load != last_load && first_load != headers) + { + /* Put the first PT_LOAD header last. */ + struct elf_segment_map *first = *first_load; + struct elf_segment_map *last = *last_load; + *first_load = first->next; + first->next = last->next; + last->next = first; + } } return TRUE; -- cgit v1.1