[Bug libc/1048] New: MIPS page size support for shared objects dlopen()ed from static ones

[Bug libc/1048] New: MIPS page size support for shared objects dlopen()ed from static ones

[macro at linux-mips dot org]

Complementing the change to support variable page sizes for MIPS, here is
an update to make getpagesize() work correctly for shared objects pulled by
dlopen() from static executables.  As the area used originally for the
auxiliary vector cannot be trusted anymore at this point, the page size is
passed from dlopen() to an auxiliary ld.so initializer explicitly.  For this
to work the RELRO segment needs to be updated, which unfortunately requires
a somewhat complicated sequence of steps to turn on write permission
beforehand and turn it off again afterwards.

 Here are the necessary changes.

2005-07-04  Maciej W. Rozycki  <macro@linux-mips.org>

        * elf/dl-reloc.c (_dl_protect_relro): Expect and handle an
        additional argument specifying protection mode to use.  Update
        error messages accordingly.
        (_dl_relocate_object): Update the call to _dl_protect_relro().
        * elf/rtld.c (dl_main): Likewise.
        * sysdeps/generic/ldsodefs.h (_dl_protect_relro): Update the
        prototype.
        * sysdeps/unix/sysv/linux/mips/dl-static.c: New file to support
        variable page size for MIPS.
	* sysdeps/unix/sysv/linux/mips/ldsodefs.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/Dist: Add dl-static.c.
	* sysdeps/unix/sysv/linux/mips/Makefile: Build dl-static in elf.
	* sysdeps/unix/sysv/linux/mips/Versions: Add _dl_var_init.

 See: "http://sourceware.org/ml/libc-alpha/2003-12/msg00159.html" for an
additional reference.

-- 
           Summary: MIPS page size support for shared objects dlopen()ed
                    from static ones
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: gotom at debian dot or dot jp
        ReportedBy: macro at linux-mips dot org
                CC: drow at false dot org,glibc-bugs at sources dot redhat
                    dot com
  GCC host triplet: mipsel-unknown-linux-gnu


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[Bug libc/1048] MIPS page size support for shared objects dlopen()ed from static ones

[macro at linux-mips dot org]

------- Additional Comments From macro at linux-mips dot org  2005-07-04 15:36 -------
Created an attachment (id=541)
 --> (http://sources.redhat.com/bugzilla/attachment.cgi?id=541&action=view)
glibc-2.3.90-20050704-mips-dl-static.patch


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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[roland at gnu dot org]

------- Additional Comments From roland at gnu dot org  2006-02-21 02:14 -------
For the trunk, mips has moved to the ports repository.
Daniel should be able to commit his fixes there directly.
Items needing merge in the 2.3 branch can be reassigned to me.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|gotom at debian dot or dot  |drow at false dot org
                   |jp                          |
             Status|NEW                         |ASSIGNED
          Component|libc                        |ports


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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[drow at sources dot redhat dot com]

------- Additional Comments From drow at sources dot redhat dot com  2006-07-24 14:18 -------
I can't approve this patch; it still touches things in elf/.  The referenced
mailing list discussion doesn't seem to have a conclusion at the end of it as to
whether they were required.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |roland at gnu dot org


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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[macro at linux-mips dot org]

------- Additional Comments From macro at linux-mips dot org  2006-07-24 14:53 -------
 The dl_pagesize variable is in the RELRO segment.  At the point
_dl_static_init() is called this segment has already been write-protected.
Therefore to initialize the variable, the segment has to be made writable
beforehand and then reset to read-only afterwards.  I have chosen to reuse
_dl_protect_relro() for fiddling with the permissions as it already has
all the necessary bits, except from the ability to specify permissions
different to currently hardcoded PROT_READ.

 If you would rather prefer another function, say _dl_unprotect_relro(),
doing the same what _dl_protect_relro() does, except from hardcoding
PROT_READ | PROT_WRITE instead, that is easily doable, but of questionable
gain.

 My understanding is IA64 currently goes away without hitting the problem,
because ld does not create the RELRO segment for this architecture as
COMMONPAGESIZE is unset.  It looks like the intent is to enable the
setting eventually (see emulparams/elf64_ia64.sh for details), which will
result in the same issue that hit me when implementing initialization of
dl_pagesize for MIPS.

 I hope this is clear enough now.

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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[drow at false dot org]

------- Additional Comments From drow at false dot org  2006-07-24 14:58 -------
Subject: Re:  MIPS page size support for shared objects dlopen()ed from static ones

On Mon, Jul 24, 2006 at 02:53:48PM -0000, macro at linux-mips dot org wrote:
>  I hope this is clear enough now.

It's clear enough to me, but I can't commit things to elf/; I'll see
what Roland says.



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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[anemo at mba dot ocn dot ne dot jp]

------- Additional Comments From anemo at mba dot ocn dot ne dot jp  2009-01-05 12:50 -------
I updated the libc-ports part of the glibc-2.3.90-20050704-mips-dl-static.patch.

See http://sourceware.org/ml/libc-ports/2009-01/msg00004.html for background.



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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[anemo at mba dot ocn dot ne dot jp]

------- Additional Comments From anemo at mba dot ocn dot ne dot jp  2009-01-05 12:55 -------
Created an attachment (id=3635)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=3635&action=view)
replacement of the libc-port part of the mips-dl-static.patch


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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[anemo at mba dot ocn dot ne dot jp]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |anemo at mba dot ocn dot ne
                   |                            |dot jp


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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[anemo at mba dot ocn dot ne dot jp]

------- Additional Comments From anemo at mba dot ocn dot ne dot jp  2009-01-08 15:00 -------
Created an attachment (id=3646)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=3646&action=view)
updated mips-dl-static.patch which does all things in ports

Looking at original patch closer, I realize that whole thing can be done in
ports.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
Attachment #3635 is|0                           |1
           obsolete|                            |


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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2009-01-27 15:33 -------
Subject: Bug 1048

CVSROOT:	/cvs/glibc
Module name:	ports
Changes by:	drow@sourceware.org	2009-01-27 15:32:55

Modified files:
	.              : ChangeLog.mips 
	sysdeps/unix/sysv/linux/mips: Makefile Versions 
Added files:
	sysdeps/unix/sysv/linux/mips: dl-static.c ldsodefs.h 

Log message:
	PR glibc/1048
	* sysdeps/unix/sysv/linux/mips/dl-static.c: New file to support
	variable page size for MIPS.
	* sysdeps/unix/sysv/linux/mips/ldsodefs.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/Makefile: Build dl-static in elf.
	* sysdeps/unix/sysv/linux/mips/Versions: Add _dl_var_init.

Patches:
http://sourceware.org/cgi-bin/cvsweb.cgi/ports/ChangeLog.mips.diff?cvsroot=glibc&r1=1.69&r2=1.70
http://sourceware.org/cgi-bin/cvsweb.cgi/ports/sysdeps/unix/sysv/linux/mips/dl-static.c.diff?cvsroot=glibc&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/ports/sysdeps/unix/sysv/linux/mips/ldsodefs.h.diff?cvsroot=glibc&r1=NONE&r2=1.1
http://sourceware.org/cgi-bin/cvsweb.cgi/ports/sysdeps/unix/sysv/linux/mips/Makefile.diff?cvsroot=glibc&r1=1.15&r2=1.16
http://sourceware.org/cgi-bin/cvsweb.cgi/ports/sysdeps/unix/sysv/linux/mips/Versions.diff?cvsroot=glibc&r1=1.9&r2=1.10



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[Bug ports/1048] MIPS page size support for shared objects dlopen()ed from static ones

[drow at sources dot redhat dot com]

------- Additional Comments From drow at sources dot redhat dot com  2009-01-27 16:52 -------
Patch checked in.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


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