Re: [AArch64] Workaround for cortex-a53 erratum 843419

[Marcus Shawcroft <marcus dot shawcroft at arm dot com>]

On 30/03/15 15:40, Marcus Shawcroft wrote:
> On 30/03/15 15:23, Marcus Shawcroft wrote:
> > Hi,
> >
> > Some early revisions of the Cortex-A53 have an erratum (843419).  The
> > details of the erratum are quite complex and involve dynamic conditions.
> >    For the purposes of the workaround we have simplified the static
> > conditions to an ADRP in the last two instructions of a 4KByte page,
> > followed within four instructions by a load/store dependent on the ADRP.
>
> In order to apply this patch to a binutils-2.25 tree the following
> prerequisite patches from trunk are also required (git hash, title, mail
> link):

Hi,

This set of patches applies to 2.24 with some minor tweaking.  In 
response to an off list request I thought it would be useful to share 
the runes for 2.24.

The following back ported patches are required, in order:

  8ef229f [AArch64] Removing unused functions.
  https://sourceware.org/ml/binutils/2015-03/msg00033.html

  e2cdef4 Remove dead code.
  https://sourceware.org/ml/binutils/2015-03/msg00294.html

  4c77202 [AArch64] Drop unused argument to
  elf_aarch64_create_or_find_stub_sec
  https://sourceware.org/ml/binutils/2015-03/msg00296.html

  2144188 [AArch64] Flip sense of erratum_835769_scan.
  https://sourceware.org/ml/binutils/2015-03/msg00297.html

  ef85752 [AArch64] Factor out common behaviour between
  elf_aarch64_create_or_find_stub_sec and elfNN_aarch64_add_stub
  https://sourceware.org/ml/binutils/2015-03/msg00298.html

  6658567 [AArch64] Factor stub creation code into
  _bfd_aarch64_create_stub_section.
  https://sourceware.org/ml/binutils/2015-03/msg00299.html

  13f622e [AArch64] Factor out _bfd_aarch64_resize_stubs()
  https://sourceware.org/ml/binutils/2015-03/msg00300.html

  35fee8b Factor out _bfd_aarch64_erratum_835769_stub_name
  https://sourceware.org/ml/binutils/2015-03/msg00302.html

  c53ed7c [OBV] Fix build -- missing ';'
  https://sourceware.org/ml/binutils/2015-03/msg00304.html

  e572930 [AArch64] Use _bfd_aarch64_add_stub_entry_in_group.
  https://sourceware.org/ml/binutils/2015-03/msg00323.html


The follow patch is required but requires some minor adjustment to cope 
with a change in the representation of section linked lists made between 
2.24 and 2.25.  A revised version of commit 5421cc5 is attached as 
patch-1.txt.

  5421cc6 [AArch64] Refactor generation of 835769 workaround stubs.
  https://sourceware.org/ml/binutils/2015-03/msg00324.html


  30068a6 [AArch64] Refactor section_group[] representation.
  https://sourceware.org/ml/binutils/2015-03/msg00327.html

  fc6d53b [AArch64] Factor out _bfd_aarch64_get_stub_for_link_section.
  https://sourceware.org/ml/binutils/2015-03/msg00328.html

  357d152 [AArch64] Adjust veneer count.
  https://sourceware.org/ml/binutils/2015-03/msg00341.html

  d9ced15 [AArch64] Remove padding before stub sections.
  https://sourceware.org/ml/binutils/2015-03/msg00343.html

  6186551 [AArch64] Implement branch over stub section.
  https://sourceware.org/ml/binutils/2015-03/msg00344.html

The 843419 workaround patch itself requires some minor adjustment to 
reflect the same linked list representation issue as above.   A revised 
version of the patch is attached as patch-2.txt.

The ChangeLog entries for the two revised patches remain unchanged from 
the original submissions.

Cheers
/Marcus

Attachment: patch-1.txt
Description: Text document

Attachment: patch-2.txt
Description: Text document