Re: PATCH: Fix .sbss for ELF/ppc64 (Re: Why does ELF/ppc expect.plt NOBITS?)

[Eric Christopher <echristo at redhat dot com>]

> > Where can I get the current ppc and ppc64 psABI? The ppc psABI I have
> > says .plt is SHT_PROGBITS and .sbss is SHT_NOBITS.
> 
> It looks like there is a typo in my copy. .plt is SHT_NOBITS. But
> what should .sbss be for ppc64? If it is SHT_NOBITS like ppc, here
> is a patch to fix testcases

Here's the relevant section out of the abi:

http://www.linuxbase.org/spec/ELF/ppc64/PPC-elf64abi.txt

Special Sections
----------------

Various sections hold program and control information.  The sections
listed in the following table are used by the system and have the
types and attributes shown.

Name          Type               Attributes

.glink        SHT_PROGBITS       SHF_ALLOC + SHF_EXECINSTR
.got          SHT_PROGBITS       SHF_ALLOC + SHF_WRITE
.toc          SHT_PROGBITS       SHF_ALLOC + SHF_WRITE
.tocbss       SHT_NOBITS         SHF_ALLOC + SHF_WRITE
.plt          SHT_NOBITS         SHF_ALLOC + SHF_WRITE

Note: the .plt section on the 64-bit PowerPC is of type SHT_NOBITS,
not SHT_PROGBITS as on most other processors.

Special sections are described below.

Name     Description

.glink   This section may be used to hold the global linkage table which
         aids the procedure linkage table. See Procedure Linkage Table
         in Chapter 5 for more information.

.got     This section may be used to hold the Global Offset Table, or
         GOT.  See The Toc Section and Coding Examples in Chapter 3
         and Global Offset Table in Chapter 5 for more information.

.toc     This section may be used to hold the initialized Table of
         Contents, or TOC.  See TOC, below, The Toc Section and Coding
         examples in Chapter 3 and Global Offset Table in Chapter 5
         for more information.

.tocbss  This section may be used to hold the uninitialized portions
         of the TOC.  This data may also be stored as zero-initialized
         data in a .toc section.

.plt     This section holds the procedure linkage table. See Procedure
         Linkage Table in Chapter 5 for more information.

Note: tools which support this ABI are not required to use these
sections precisely as defined here, and indeed are not required to use
them at all.  The true use of a section is defined by the relocation
information and by the code which refers to it.  However, if tools use
these sections, they are required to give them the types and
attributes specified in the above table.


-eric

-- 
Eric Christopher <echristo@redhat.com>