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.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 97d37265163e6e22f89dc47ad7f5f0df86c8b702..a725504c025473d20278ff6e5979935e8a1b2bdc 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,11 @@
+2019-08-22  Alan Modra  <amodra@gmail.com>
+
+       * 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  <dennis.zhang@arm.com>
 
        * cpu-aarch64.c: New entries for Cortex-A34, Cortex-A65,

diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index d1548d6db331e630b1e3998c1016fdab42e578b8..b675fc60c1ac82393a1cb05e67a3f4ec2c4b84cc 100644 (file)
--- 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 1813cb38d8e290e74a9a1a3ac61491375da11cc2..e779c177023786babd2bf4b93b640f18d639701d 100644 (file)
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,7 @@
+2019-08-22  Alan Modra  <amodra@gmail.com>
+
+       * elf/arm.h (ARM_GET_SYM_CMSE_SPCL, ARM_SET_SYM_CMSE_SPCL): Delete.
+
 2019-08-09  Mihailo Stojanovic  <mihailo.stojanovic@rt-rk.com>
 
        * elf/mips.h (SHT_GNU_XHASH): New define.

diff --git a/include/elf/arm.h b/include/elf/arm.h
index 5cb99706443838cd2d43accab9e713d53304bd00..75fb5e26ca0b482c7f693d31e66ee78b1254be5b 100644 (file)
--- 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 */