[Buildroot] crosstool-ng and uClibc toolchain

[Buildroot] crosstool-ng and uClibc toolchain

[Will Wagner]

Hi,

I have been looking at building a toolchain using 2011.11 building it 
with crosstools-ng and uClibc.

It currently seems a little bit broken/limited. I can supply a custom 
ct-ng config, which specifies 0.9.32 but I am unable to select NPTL 
threading or to specify a custom uClibc config file.

Also if I choose to use libthreads.new then the build fails as the 
config file passed to build libc headers has no threading option 
enabled. This problem is I think caused by the uClibc config file you 
have to use. It contains LINUXTHREADS_OLD=y but there is not a not set 
entry for LINUXTHREADS_NEW which means the sed command to set it can't work.

In fact the uClibc config you are forced to use has lots of settings I 
would consider wrong.

Am I correct thinking these things are broken or am I missing something?

Am currently working on a patch that does the following:
- Allow user to pick uClibc version when using ct-ng
- Allow user to select nptl when using 0.9.32
- Supply better default uClibc config files (Using same config files as 
for internal buildroot config)
- Allow user to specify a custom uClibc config file

Assuming I can get it working I'll post it.

Thanks
Will
-- 
------------------------------------------------------------------------
Will Wagner                                     will_wagner at carallon.com
Development Manager                      Office Tel: +44 (0)20 7371 2032
Carallon Ltd, Studio G20, Shepherds Building, Rockley Rd, London W14 0DA
------------------------------------------------------------------------

[Buildroot] crosstool-ng and uClibc toolchain

[Thomas Petazzoni]

Le Fri, 02 Dec 2011 14:44:11 +0000,
Will Wagner <will_wagner@carallon.com> a ?crit :

> In fact the uClibc config you are forced to use has lots of settings I 
> would consider wrong.
> 
> Am I correct thinking these things are broken or am I missing something?

I haven't fallen into these issues as I'm not using the ct-ng backend
a lot (I do use ct-ng outside of Buildroot in general).

> Am currently working on a patch that does the following:
> - Allow user to pick uClibc version when using ct-ng
> - Allow user to select nptl when using 0.9.32
> - Supply better default uClibc config files (Using same config files as 
> for internal buildroot config)
> - Allow user to specify a custom uClibc config file

Those sounds like good ideas, especially the sharing the uClibc config
files between the internal build process and the ct-ng build process.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] crosstool-ng and uClibc toolchain

[Yann E. MORIN]

Will, All,

On Friday 02 December 2011 15:44:11 Will Wagner wrote:
> I have been looking at building a toolchain using 2011.11 building it 
> with crosstools-ng and uClibc.
> 
> It currently seems a little bit broken/limited. I can supply a custom 
> ct-ng config, which specifies 0.9.32 but I am unable to select NPTL 
> threading or to specify a custom uClibc config file.

Yes, indeed. The problem is that buildroot has no way of knowing what
version of uClibc will be chosen in the crosstool-Ng configuration, so
there is no way to know if NPTL is available or not.

Nothe, that's the current state, not what we want. ;-)

> Also if I choose to use libthreads.new then the build fails as the 
> config file passed to build libc headers has no threading option 
> enabled. This problem is I think caused by the uClibc config file you 
> have to use. It contains LINUXTHREADS_OLD=y but there is not a not set 
> entry for LINUXTHREADS_NEW which means the sed command to set it can't work.

OK, I see the issue. Maybe something like:

if LT_NEW:
  s/^(CT_LIBC_UCLIBC_LNXTHRD_)(NEW|OLD)=y/\1_NEW=y/;
  s/^(CT_LIBC_UCLIBC_LNXTHRD_OLD)=y/# \1 is not set/;
elif LT_OLD:
  s/^(CT_LIBC_UCLIBC_LNXTHRD_)(NEW|OLD)=y/\1_OLD=y/;
  s/^(CT_LIBC_UCLIBC_LNXTHRD_NEW)=y/# \1 is not set/;
endif

(Not taking NPTL into account, that should be another patch).

> In fact the uClibc config you are forced to use has lots of settings I 
> would consider wrong.
> Am I correct thinking these things are broken or am I missing something?

They are not what I would call 'wrong', because these default settings do
provide a working toolchain, by _default_.

Surely, all that sed mangling is complex...

But I agree that the situation could be enhanced...

> Am currently working on a patch that does the following:
> - Allow user to pick uClibc version when using ct-ng
> - Allow user to select nptl when using 0.9.32
> - Supply better default uClibc config files (Using same config files as 
> for internal buildroot config)
> - Allow user to specify a custom uClibc config file
> 
> Assuming I can get it working I'll post it.

Please, keep me in CC, so I do not miss the message...

Regards,
Yann E. MORIN.

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| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
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[Buildroot] crosstool-ng and uClibc toolchain

[Michael S. Zick]

On Fri December 2 2011, Yann E. MORIN wrote:
> But I agree that the situation could be enhanced...
> 
> > Am currently working on a patch that does the following:
> > - Allow user to pick uClibc version when using ct-ng
> > - Allow user to select nptl when using 0.9.32
> > - Supply better default uClibc config files (Using same config files as 
> > for internal buildroot config)
> > - Allow user to specify a custom uClibc config file
> > 
> > Assuming I can get it working I'll post it.
> 
> Please, keep me in CC, so I do not miss the message...
> 

In case you already missed it, five hours ago:
http://lists.busybox.net/pipermail/buildroot/2011-December/048033.html

Mike

[Buildroot] crosstool-ng and uClibc toolchain

[Yann E. MORIN]

Mike, All,

On Friday 02 December 2011 22:37:30 Michael S. Zick wrote:
> On Fri December 2 2011, Yann E. MORIN wrote:
> > But I agree that the situation could be enhanced...
> > 
> > > Am currently working on a patch that does the following:
> > > - Allow user to pick uClibc version when using ct-ng
> > > - Allow user to select nptl when using 0.9.32
> > > - Supply better default uClibc config files (Using same config files as 
> > > for internal buildroot config)
> > > - Allow user to specify a custom uClibc config file
> > > 
> > > Assuming I can get it working I'll post it.
> > 
> > Please, keep me in CC, so I do not miss the message...
> > 
> 
> In case you already missed it, five hours ago:
> http://lists.busybox.net/pipermail/buildroot/2011-December/048033.html

Yep, I saw it afterwards; I'm currently reviewing and commenting it.
Thanks! :-)

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'