[RFC PATCH, binutils, ARM 11/11, ping] Add support for stable secure gateway veneers addresses

[Thomas Preudhomme]

Hi Christophe,

On 29/08/16 15:56, Christophe Lyon wrote:
> On 26 August 2016 at 16:18, Thomas Preudhomme
> <thomas.preudhomme@foss.arm.com> wrote:
>> On 26/08/16 13:36, Thomas Preudhomme wrote:
>>>
>>> Hi Christophe,
>>>
>>> On 26/08/16 12:55, Christophe Lyon wrote:
>>>>
>>>>
>>>> I've noticed that the new tests fail on armeb. I didn't look at the
>>>> detailed logs yet, but I guess you can a look?
>>>>
>>>> ./ld/ld.sum:FAIL: Input secure gateway import library
>>>> ./ld/ld.sum:FAIL: Input secure gateway import library: no output import
>>>> library
>>>> ./ld/ld.sum:FAIL: Input secure gateway import library: earlier stub
>>>> section base
>>>> ./ld/ld.sum:FAIL: Input secure gateway import library: later stub section
>>>> base
>>>> ./ld/ld.sum:FAIL: Input secure gateway import library: veneer comeback
>>>> ./ld/ld.sum:FAIL: Input secure gateway import library: entry function
>>>> change
>>>
>>>
>>> I can reproduce indeed. I'll have a look, thanks for the notice. Note that
>>> Monday is a bank holidays here so might only answer after that if I'm too
>>> slow
>>> to find the root cause.
>>
>>
>> Doh, the code checks for a SG instruction by comparing the 4 bytes in the
>> code against its litteral value. The problem of course is that the read puts
>> the 4 bytes of the instruction in memory order but these will then be
>> interpreted according to the endianness.
>>
>> The fix should be easy.
>>
>
> Indeed, thanks to your analysis it was quick enough.
>
> Here is a patch, maybe there is a simpler way?

diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 9ff418a..5c04b9b 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -5791,11 +5791,19 @@ cmse_entry_fct_p (struct elf32_arm_link_hash_entry *hash)
    section = hash->root.root.u.def.section;
    abfd = section->owner;
    offset = hash->root.root.u.def.value - section->vma;
-  if (!bfd_get_section_contents (abfd, section, &first_insn, offset,
-				 sizeof (first_insn)))
-    return FALSE;

    /* Start by SG instruction.  */
+  bfd_byte * contents;
+  /* Get cached copy if it exists.  */
+  if (elf_section_data (section)->this_hdr.contents != NULL)
+    contents = elf_section_data (section)->this_hdr.contents;
+  else
+    {
+      /* Go get them off disk.  */
+      if (! bfd_malloc_and_get_section (abfd, section, &contents))
+	return FALSE;
+    }
+  first_insn = bfd_get_32 (abfd, contents + offset);
    return first_insn == 0xe97fe97f;
  }

I have a similar patch but I'm still using bfd_get_section_contents with a 4byte 
buffer named contents. It avoids reading the entire section to just analyze 4 
bytes. I did it on Friday so wanted to test it a bit more today.

Best regards,

Thomas