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Re: [Patch, microblaze]: Add a small Linux BSP

On 07/26/13 07:54, David Holsgrove wrote:
-----Original Message-----
From: Michael Eager []
Sent: Friday, 26 July 2013 1:17 pm
To: Edgar Iglesias
Cc: David Holsgrove;;; Edgar
Subject: Re: [Patch, microblaze]: Add a small Linux BSP

On 07/25/13 19:43, Edgar E. Iglesias wrote:
On Fri, Jul 26, 2013 at 04:10:51AM +0200, David Holsgrove wrote:
-----Original Message-----
From: Michael Eager []
Sent: Friday, 26 July 2013 11:43 am
To:;; David Holsgrove
Subject: Re: [Patch, microblaze]: Add a small Linux BSP

On 07/23/13 02:11, Corinna Vinschen wrote:
On Jul 23 17:16, David Holsgrove wrote:
On 23 July 2013 17:10, Corinna Vinschen <> wrote:
On Jul 23 16:25, David Holsgrove wrote:
From: "David Holsgrove" <...>


2013-07-23  Edgar E. Iglesias <...>

     * microblaze/ Add LINUX_BSP.
     * microblaze/elf-gloss-linux.ld: New file.
     * microblaze/elf-gloss-linux.specs: Likewise.
     * microblaze/linux-crt0.S: Likewise.
     * microblaze/linux-inbyte.c: Likewise.
     * microblaze/linux-outbyte.c: Likewise.
     * microblaze/linux-syscalls-wrap.c: Likewise.
     * microblaze/linux-syscalls.S: Likewise.
     * microblaze/linux-syscalls.h: Likewise.

Please apply.

Thanks Corinna,

I don't have write perms on newlib - can I request them, or can you
apply the patch for me?

Everything applied.

This patch breaks breaks existing mb-gcc compilations.

Please revert the patch until it can be fixed.

Hi Michael,

Can you provide details regarding the breakage?

This should be a separate library and not linked in by default - what sort
of compilation errors are you seeing?

libgloss/sbrk.o is being linked into executables instead of
libgloss/microblaze/sbrk.o, which results in an unresolved reference to _end.

Here is a sample test:
mb-gcc testsuite/gcc.c-torture/execute/strcpy-1.c  -fno-diagnostics-show-caret
-fdiagnostics-color=never  -w  -O3 -fomit-frame-pointer  -mno-xl-soft-mul
-mxl-barrel-shift -mcpu=v6.00.a -Wl,-defsym -Wl,_HEAP_SIZE=0x1000000 -Wl,-
-Wl,_STACK_SIZE=0x80000 -L microblaze_0/lib -lxil
-TLinkScr.ld  -lm   -o strcpy-1.x3

LinkScr.ld and libxil are from either EDK9.2i or EDK-14.2.

I don't have the failure log at the moment.

Thanks Michael for the details.

I've managed to recreate the unresolved reference to _end you see with your
testcase, but only by using the linker script you provided to me in the past from
EDK9.2i - when using your LinkScr.ld from EDK-14.2 I don't see any undefs.

Thanks for investigating this.

The reason for this is that the linker script generated by libgen in XSDK 14.2 (and since
at least XSDK version 13.1 it would appear) includes;

_end = .;

This is why our testing succeed where yours didnât - we were using more modern
versions of XSDK to provide libxil and the linker script - but this is actually just
masking a configuration error.


The patch added in utilised
the existing libgloss target_makefile_frag to define generic objects to be linked
into libgloss.a - something which has long been missing for microblaze in FSF newlib.

What I didnât see was that even though we made no changes to the sbrk.c compile
stage, the inclusion of libgloss/config/ overrides where sbrk.c came from,
using the generic libgloss/sbrk.c instead of the libgloss/microblaze/sbrk.c copy.

The differences between these two are quite small - and perhaps should be addressed
in a future patch to reduce the amount of microblaze specific variants for you to maintain,
but most importantly _end is used in the generic instead of _heap in the microblaze copy;

   if (!heap_ptr)
     heap_ptr = (char *)&_end;
   base = heap_ptr;
   heap_ptr += nbytes;

   if (!heap_ptr)
     heap_ptr = (char *)&_heap;
   base = heap_ptr;
   heap_ptr += nbytes;

Yes, I don't see a good reason that there are microblaze-specific routines which
provide the same functionality as the generic functions.

So in summary, the libgloss-linux.a added by the patch in this thread does not cause any

I didn't think that a Linux-specific library which was not included in my tests
caused a regression.

The patch added in should
be amended to ensure microblaze/sbrk.c is used for the moment - I'll provide a patch
to do so now.


We should also establish a common test framework for microblaze targets to avoid
difference such as these in future which can be triggered by varying versions of Xilinx
provided tools.

I've suggested this for quite a few months.

I donât suppose your dejagnu boards are available through GNU's dejagnu project?
This can be discussed off list, as I believe this thread has already gotten off the topic
of adding this LINUX_BSP.

The MB test configuration is not in the DejaGNU project.

Michael Eager
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077

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