Re: PING^3: [PATCH 1/2] Add ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA to x86

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Mar 25, 2015 at 4:33 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Wed, Mar 18, 2015 at 7:43 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Wed, Mar 11, 2015 at 10:24 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Mar 5, 2015 at 4:19 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>>> With copy relocation, address of protected data defined in the shared
>>>> library may be external.   When there is a relocation against the
>>>> protected data symbol within the shared library, we need to check if we
>>>> should skip the definition in the executable copied from the protected
>>>> data.  This patch adds ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA and defines
>>>> it for x86.  If ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA isn't 0, do_lookup_x
>>>> will skip the data definition in the executable from copy reloc.
>>>>
>>>> I only defined DL_EXTERN_PROTECTED_DATA for x86.  Other targets can
>>>> define DL_EXTERN_PROTECTED_DATA and update elf_machine_type_class to
>>>> support copy relocation on protected data.
>>>>
>>>> I will submit a testcase in a separate email.
>>>>
>>>> Tested on x86-32 and x86-64.  OK for master?
>>>>
>>>> Thanks.
>>>>
>>>> H.J.
>>>> ---
>>>>         [BZ #17711]
>>>>         * elf/dl-lookup.c (do_lookup_x): When UNDEF_MAP is NULL, which
>>>>         indicates it is called from do_lookup_x on relocation against
>>>>         protected data, skip the data definion in the executable from
>>>>         copy reloc.
>>>>         (_dl_lookup_symbol_x): Pass ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA,
>>>>         instead of ELF_RTYPE_CLASS_PLT, to do_lookup_x for
>>>>         EXTERN_PROTECTED_DATA relocation against STT_OBJECT symbol.
>>>>         * sysdeps/generic/ldsodefs.h * (ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA):
>>>>         New.  Defined to 4 if DL_EXTERN_PROTECTED_DATA is defined,
>>>>         otherwise to 0.
>>>>         * sysdeps/i386/dl-lookupcfg.h (DL_EXTERN_PROTECTED_DATA): New.
>>>>         * sysdeps/i386/dl-machine.h (elf_machine_type_class): Set class
>>>>         to ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA for R_386_GLOB_DAT.
>>>>         * sysdeps/x86_64/dl-lookupcfg.h (DL_EXTERN_PROTECTED_DATA): New.
>>>>         * sysdeps/x86_64/dl-machine.h (elf_machine_type_class): Set class
>>>>         to ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA for R_X86_64_GLOB_DAT.
>>>
>>> PING.
>>
>> PING.
>>
>
> Any comments, objections?  The patch is at
>
> https://sourceware.org/ml/libc-alpha/2015-03/msg00230.html
>

GCC bug has been fixed for GCC 5.  I will check in this patch
on Tuesday, March 31.

-- 
H.J.