From a91e1603afb6704545793e967a1a3dfe96b389de Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 4 Apr 2017 09:05:48 -0700 Subject: Support ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX Mark an ALLOC section, which should be placed in special memory area, with SHF_GNU_MBIND. Its sh_info field indicates the special memory type. GNU_MBIND section names start with ".mbind" so that they are placed as orphan sections by linker. All input GNU_MBIND sections with the same sh_type, sh_flags and sh_info are placed in one output GNU_MBIND section. In executable and shared object, create a GNU_MBIND segment for each GNU_MBIND section and its segment type is PT_GNU_MBIND_LO plus the sh_info value. Each GNU_MBIND segment is aligned at page boundary. The assembler syntax: .section .mbind.foo,"adx",%progbits ^ 0: Special memory type. | 'd' for SHF_GNU_MBIND. .section .mbind.foo,"adx",%progbits,0x1 ^ 1: Special memory type. | 'd' for SHF_GNU_MBIND. .section .mbind.bar,"adG",%progbits,.foo_group,comdat,0x2 ^ 2: Special memory type. | 'd' for SHF_GNU_MBIND. bfd/ * elf.c (get_program_header_size): Add a GNU_MBIND segment for each GNU_MBIND section and align GNU_MBIND section to page size. (_bfd_elf_map_sections_to_segments): Create a GNU_MBIND segment for each GNU_MBIND section. (_bfd_elf_init_private_section_data): Copy sh_info from input for GNU_MBIND section. binutils/ * NEWS: Mention support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX. * readelf.c (get_segment_type): Handle PT_GNU_MBIND_XXX. (get_elf_section_flags): Handle SHF_GNU_MBIND. (process_section_headers): Likewise. * testsuite/binutils-all/mbind1.s: New file. * testsuite/binutils-all/objcopy.exp: Run readelf test on mbind1.s. gas/ * NEWS: Mention support for ELF SHF_GNU_MBIND. * config/obj-elf.c (section_match): New. (get_section): Match both sh_info and group name. (obj_elf_change_section): Add argument for sh_info. Pass both sh_info and group name to get_section. Issue an error for SHF_GNU_MBIND section without SHF_ALLOC. Set sh_info. (obj_elf_parse_section_letters): Set SHF_GNU_MBIND for 'd'. (obj_elf_section): Support SHF_GNU_MBIND section info. * config/obj-elf.h (obj_elf_change_section): Add argument for sh_info. * config/tc-arm.c (start_unwind_section): Pass 0 as sh_info to obj_elf_change_section. * config/tc-ia64.c (obj_elf_vms_common): Likewise. * config/tc-microblaze.c (microblaze_s_data): Likewise. (microblaze_s_sdata): Likewise. (microblaze_s_rdata): Likewise. (microblaze_s_bss): Likewise. * config/tc-mips.c (s_change_section): Likewise. * config/tc-msp430.c (msp430_profiler): Likewise. * config/tc-rx.c (parse_rx_section): Likewise. * config/tc-tic6x.c (tic6x_start_unwind_section): Likewise. * doc/as.texinfo: Document 'd' for SHF_GNU_MBIND. * testsuite/gas/elf/elf.exp: Run section12a, section12b and section13. * testsuite/gas/elf/section10.d: Updated. * testsuite/gas/elf/section10.s: Likewise. * testsuite/gas/elf/section12.s: New file. * testsuite/gas/elf/section12a.d: Likewise. * testsuite/gas/elf/section12b.d: Likewise. * testsuite/gas/elf/section13.l: Likewise. * testsuite/gas/elf/section13.d: Likewise. * testsuite/gas/elf/section13.s: Likewise. include/ * elf/common.h (PT_GNU_MBIND_NUM): New. (PT_GNU_MBIND_LO): Likewise. (PT_GNU_MBIND_HI): Likewise. (SHF_GNU_MBIND): Likewise. ld/ * NEWS: Mention support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX. * emultempl/elf32.em (gld${EMULATION_NAME}_place_orphan): Place input GNU_MBIND sections with the same type, attributes and sh_info field into a single output GNU_MBIND section. * testsuite/ld-elf/elf.exp: Run mbind2a and mbind2b. * testsuite/ld-elf/mbind1.s: New file. * testsuite/ld-elf/mbind1a.d: Likewise. * testsuite/ld-elf/mbind1b.d: Likewise. * testsuite/ld-elf/mbind1c.d: Likewise. * testsuite/ld-elf/mbind2a.s: Likewise. * testsuite/ld-elf/mbind2b.c: Likewise. --- bfd/elf.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 64 insertions(+), 2 deletions(-) (limited to 'bfd/elf.c') diff --git a/bfd/elf.c b/bfd/elf.c index d4d91b6..dcb0e6f 100644 --- a/bfd/elf.c +++ b/bfd/elf.c @@ -4330,9 +4330,33 @@ get_program_header_size (bfd *abfd, struct bfd_link_info *info) } } - /* Let the backend count up any program headers it might need. */ bed = get_elf_backend_data (abfd); - if (bed->elf_backend_additional_program_headers) + + if ((abfd->flags & D_PAGED) != 0) + { + /* Add a PT_GNU_MBIND segment for each mbind section. */ + unsigned int page_align_power = bfd_log2 (bed->commonpagesize); + for (s = abfd->sections; s != NULL; s = s->next) + if (elf_section_flags (s) & SHF_GNU_MBIND) + { + if (elf_section_data (s)->this_hdr.sh_info + > PT_GNU_MBIND_NUM) + { + _bfd_error_handler + /* xgettext:c-format */ + (_("%B: GNU_MBIN section `%A' has invalid sh_info field: %d"), + abfd, s, elf_section_data (s)->this_hdr.sh_info); + continue; + } + /* Align mbind section to page size. */ + if (s->alignment_power < page_align_power) + s->alignment_power = page_align_power; + segs ++; + } + } + + /* Let the backend count up any program headers it might need. */ + if (bed->elf_backend_additional_program_headers) { int a; @@ -4504,6 +4528,7 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info) bfd_boolean writable; int tls_count = 0; asection *first_tls = NULL; + asection *first_mbind = NULL; asection *dynsec, *eh_frame_hdr; bfd_size_type amt; bfd_vma addr_mask, wrap_to = 0; @@ -4836,6 +4861,9 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info) first_tls = s; tls_count++; } + if (first_mbind == NULL + && (elf_section_flags (s) & SHF_GNU_MBIND) != 0) + first_mbind = s; } /* If there are any SHF_TLS output sections, add PT_TLS segment. */ @@ -4883,6 +4911,35 @@ _bfd_elf_map_sections_to_segments (bfd *abfd, struct bfd_link_info *info) pm = &m->next; } + if (first_mbind && (abfd->flags & D_PAGED) != 0) + for (s = first_mbind; s != NULL; s = s->next) + if ((elf_section_flags (s) & SHF_GNU_MBIND) != 0 + && (elf_section_data (s)->this_hdr.sh_info + <= PT_GNU_MBIND_NUM)) + { + /* Mandated PF_R. */ + unsigned long p_flags = PF_R; + if ((s->flags & SEC_READONLY) == 0) + p_flags |= PF_W; + if ((s->flags & SEC_CODE) != 0) + p_flags |= PF_X; + + amt = sizeof (struct elf_segment_map) + sizeof (asection *); + m = bfd_zalloc (abfd, amt); + if (m == NULL) + goto error_return; + m->next = NULL; + m->p_type = (PT_GNU_MBIND_LO + + elf_section_data (s)->this_hdr.sh_info); + m->count = 1; + m->p_flags_valid = 1; + m->sections[0] = s; + m->p_flags = p_flags; + + *pm = m; + pm = &m->next; + } + /* If there is a .eh_frame_hdr section, throw in a PT_GNU_EH_FRAME segment. */ eh_frame_hdr = elf_eh_frame_hdr (abfd); @@ -7359,6 +7416,11 @@ _bfd_elf_init_private_section_data (bfd *ibfd, elf_section_flags (osec) |= (elf_section_flags (isec) & (SHF_MASKOS | SHF_MASKPROC)); + /* Copy sh_info from input for mbind section. */ + if (elf_section_flags (isec) & SHF_GNU_MBIND) + elf_section_data (osec)->this_hdr.sh_info + = elf_section_data (isec)->this_hdr.sh_info; + /* Set things up for objcopy and relocatable link. The output SHT_GROUP section will have its elf_next_in_group pointing back to the input group members. Ignore linker created group section. -- cgit v1.1