From baf46cd78048e1b959462567556e1de1ef6b9039 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Thu, 22 Aug 2019 11:21:48 +0930 Subject: [PATCH 1/1] ARM CMSE symbols This patch removes use of st_target_internal to cache the result of comparing symbol names against CMSE_PREFIX. The problem with setting a bit in st_target_internal in swap_symbol_in is that calling bfd_elf_sym_name from swap_symbol_in requires symtab_hdr, and you don't know for sure whether swap_symbol_in is operating on dynsyms (and thus elf_tdata (abfd)->dynsymtab_hdr should be used) or on the normal symtab (thus elf_tdata (abfd)->symtab_hdr). You can make an educated guess based on abfd->flags & DYNAMIC but that relies on knowing a lot about calls to bfd_elf_get_elf_syms, and is fragile in the face of possible future changes. include/ * elf/arm.h (ARM_GET_SYM_CMSE_SPCL, ARM_SET_SYM_CMSE_SPCL): Delete. bfd/ * elf32-arm.c (cmse_scan): Don't use ARM_GET_SYM_CMSE_SPCL, instead recognize CMSE_PREFIX in symbol name. (elf32_arm_gc_mark_extra_sections): Likewise. (elf32_arm_filter_cmse_symbols): Don't test ARM_GET_SYM_CMSE_SPCL. (elf32_arm_swap_symbol_in): Don't invoke ARM_SET_SYM_CMSE_SPCL. --- bfd/ChangeLog | 8 ++++++++ bfd/elf32-arm.c | 26 ++++++-------------------- include/ChangeLog | 4 ++++ include/elf/arm.h | 7 ------- 4 files changed, 18 insertions(+), 27 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 97d3726..a725504 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,11 @@ +2019-08-22 Alan Modra + + * elf32-arm.c (cmse_scan): Don't use ARM_GET_SYM_CMSE_SPCL, + instead recognize CMSE_PREFIX in symbol name. + (elf32_arm_gc_mark_extra_sections): Likewise. + (elf32_arm_filter_cmse_symbols): Don't test ARM_GET_SYM_CMSE_SPCL. + (elf32_arm_swap_symbol_in): Don't invoke ARM_SET_SYM_CMSE_SPCL. + 2019-08-20 Dennis Zhang * cpu-aarch64.c: New entries for Cortex-A34, Cortex-A65, diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c index d1548d6..b675fc6 100644 --- a/bfd/elf32-arm.c +++ b/bfd/elf32-arm.c @@ -6002,12 +6002,12 @@ cmse_scan (bfd *input_bfd, struct elf32_arm_link_hash_table *htab, if (i < ext_start) { cmse_sym = &local_syms[i]; - /* Not a special symbol. */ - if (!ARM_GET_SYM_CMSE_SPCL (cmse_sym->st_target_internal)) - continue; sym_name = bfd_elf_string_from_elf_section (input_bfd, symtab_hdr->sh_link, cmse_sym->st_name); + if (!sym_name || !CONST_STRNEQ (sym_name, CMSE_PREFIX)) + continue; + /* Special symbol with local binding. */ cmse_invalid = TRUE; } @@ -6015,9 +6015,7 @@ cmse_scan (bfd *input_bfd, struct elf32_arm_link_hash_table *htab, { cmse_hash = elf32_arm_hash_entry (sym_hashes[i - ext_start]); sym_name = (char *) cmse_hash->root.root.root.string; - - /* Not a special symbol. */ - if (!ARM_GET_SYM_CMSE_SPCL (cmse_hash->root.target_internal)) + if (!CONST_STRNEQ (sym_name, CMSE_PREFIX)) continue; /* Special symbol has incorrect binding or type. */ @@ -15990,7 +15988,8 @@ elf32_arm_gc_mark_extra_sections (struct bfd_link_info *info, /* Assume it is a special symbol. If not, cmse_scan will warn about it and user can do something about it. */ - if (ARM_GET_SYM_CMSE_SPCL (cmse_hash->root.target_internal)) + if (CONST_STRNEQ (cmse_hash->root.root.root.string, + CMSE_PREFIX)) { cmse_sec = cmse_hash->root.root.u.def.section; if (!cmse_sec->gc_mark @@ -18610,9 +18609,6 @@ elf32_arm_filter_cmse_symbols (bfd *abfd ATTRIBUTE_UNUSED, || cmse_hash->root.type != STT_FUNC) continue; - if (!ARM_GET_SYM_CMSE_SPCL (cmse_hash->root.target_internal)) - continue; - syms[dst_count++] = sym; } free (cmse_name); @@ -19935,9 +19931,6 @@ elf32_arm_swap_symbol_in (bfd * abfd, const void *pshn, Elf_Internal_Sym *dst) { - Elf_Internal_Shdr *symtab_hdr; - const char *name = NULL; - if (!bfd_elf32_swap_symbol_in (abfd, psrc, pshn, dst)) return FALSE; dst->st_target_internal = 0; @@ -19966,13 +19959,6 @@ elf32_arm_swap_symbol_in (bfd * abfd, else ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal, ST_BRANCH_UNKNOWN); - /* Mark CMSE special symbols. */ - symtab_hdr = & elf_symtab_hdr (abfd); - if (symtab_hdr->sh_size) - name = bfd_elf_sym_name (abfd, symtab_hdr, dst, NULL); - if (name && CONST_STRNEQ (name, CMSE_PREFIX)) - ARM_SET_SYM_CMSE_SPCL (dst->st_target_internal); - return TRUE; } diff --git a/include/ChangeLog b/include/ChangeLog index 1813cb3..e779c17 100644 --- a/include/ChangeLog +++ b/include/ChangeLog @@ -1,3 +1,7 @@ +2019-08-22 Alan Modra + + * elf/arm.h (ARM_GET_SYM_CMSE_SPCL, ARM_SET_SYM_CMSE_SPCL): Delete. + 2019-08-09 Mihailo Stojanovic * elf/mips.h (SHT_GNU_XHASH): New define. diff --git a/include/elf/arm.h b/include/elf/arm.h index 5cb9970..75fb5e2 100644 --- a/include/elf/arm.h +++ b/include/elf/arm.h @@ -399,11 +399,4 @@ enum arm_st_branch_type { | ((TYPE) & ENUM_ARM_ST_BRANCH_TYPE_BITMASK)) #endif -/* Get or set whether a symbol is a special symbol of an entry function of CMSE - secure code. */ -#define ARM_GET_SYM_CMSE_SPCL(SYM_TARGET_INTERNAL) \ - (((SYM_TARGET_INTERNAL) >> 2) & 1) -#define ARM_SET_SYM_CMSE_SPCL(SYM_TARGET_INTERNAL) \ - (SYM_TARGET_INTERNAL) |= 4 - #endif /* _ELF_ARM_H */ -- 2.7.4