Can't build libpthread for M3

Thu Oct 23 09:45:20 UTC 2014

Hello,

On Wed, 22 Oct 2014 20:53:52 +0300
Andrii <bearrailgun at gmail.com> wrote:

> Thanks for the patches!
> 
> I've tried to apply both on uClibc-0.9.33.2 (latest official release).
> uclibc-cm3-clone.patch was applied just well.
> But I was not able to apply uclibc-cm3-testandset.patch correctly:
> In libpthread/linuxthreads.old/sysdeps/arm/pt-machine.h
> I don't have next lines:
> -  int unused = 0;
> -  return INTERNAL_SYSCALL_ARM (atomicops, , 4, SYS_ARM_ATOMIC_SET,
> -                         spinlock, 1, unused);

Yes, just skip that part of the patch.

> But rest seems the same.
> So I fixed it manually by copying ldrex/strex and testandset
> functions. This patch also creates dot_config_pthreads-no-ldrex which
> I used to build uclibc (also I enabled the USE_LDREXSTREX=y)
> 

Correct.

> The result is next (In app just usual pthread_create() used without
> any other pthread calls) :
> # ./the_app
> 00026 : pthread_initialize: initial thread stack bounds: bos=0x1,
> tos=0xffffffff
> the_app started. version 6.76_threads
> Starting sensor simulation thread
> 00026 : __pthread_initialize_manager: manager stack: size=8160,
> bos=0xa0696008, tos=0xa0697fe8
> 00026 : __pthread_initialize_manager: send REQ_DEBUG to manager thread
> 00026 : pthread_create: write REQ_CREATE to manager thread
> 00026 : pthread_create: before suspend(self)
> [   18.810000]
> [   18.810000]
> [   18.810000] the_app: unhandled MPU fault (0x08) at 0x00000000
> [pc=0xa0583ea8,sp=0xa0697fc0]
> [   18.810000]
> 
> Actually I have same results on latest uclibc git without fixing clone
> patch but with ldrex/strex fix.
> 
> Any suggestions are welcome.
> 

Looks like your build flags are not optimal for Cortex-M3. You are
building as "march=armv7-m -mthumb".
Try:
make -s ARCH_CFLAGS= 'CPU_CFLAGS=-mthumb -march=armv7 -mfix-cortex-m3-ldrd'

Also, make sure your application doesn't use big arrays located in stack.
By default, stack size is only 4K for the Cortex-M applications.
See arm-uclinuxeabi-flthdr utility to display and change the stack size.

Regards,

Sergei
> Regards.
> 
> 
> 
> On Wed, Oct 22, 2014 at 1:11 PM, Sergei Poselenov
> <sposelenov at emcraft.com> wrote:
> 
> > Hello,
> >
> > On Thu, 9 Oct 2014 23:29:01 +0300
> > Andrii <bearrailgun at gmail.com> wrote:
> >
> > > I'm trying to build uClibc for Cortex-M3 LPC17XX with codesourcery
> > > g++ lite arm2010q1(189) toolchain.
> > > I've tried 0.9.30.3, 0.9.33.2 and latest git a9bdc5d2 with almost
> > > same results.
> > > Here is the output from latest git:
> > >
> > > When trying to build with old linuxthreads:
> > >   CC libpthread/linuxthreads.old/mutex.os
> > > /tmp/ccB7JHC6.s: Assembler messages:
> > > /tmp/ccB7JHC6.s:29: Error: selected processor does not support ARM
> > > opcodes /tmp/ccB7JHC6.s:30: Error: attempt to use an ARM
> > > instruction on a Thumb-only processor -- `swp r3,r3,[r0]'
> > > /tmp/ccB7JHC6.s:31: Error: attempt to use an ARM instruction on a
> > > Thumb-only processor -- `orr r0,pc,#1'
> > > /tmp/ccB7JHC6.s:32: Error: attempt to use an ARM instruction on a
> > > Thumb-only processor -- `bx r0'
> > > /tmp/ccB7JHC6.s:58: Error: selected processor does not support ARM
> > > opcodes /tmp/ccB7JHC6.s:59: Error: attempt to use an ARM
> > > instruction on a Thumb-only processor -- `swp r2,r2,[r0]'
> > > /tmp/ccB7JHC6.s:60: Error: attempt to use an ARM instruction on a
> > > Thumb-only processor -- `orr r0,pc,#1'
> > > /tmp/ccB7JHC6.s:61: Error: attempt to use an ARM instruction on a
> > > Thumb-only processor -- `bx r0'
> > > make: *** [libpthread/linuxthreads.old/mutex.os] Error 1
> > >
> > > New linux threads:
> > >   CC libpthread/linuxthreads/sysdeps/arm/pspinlock.os
> > > In file included from ./libpthread/linuxthreads/descr.h:46,
> > >                  from ./libpthread/linuxthreads/internals.h:36,
> > >                  from
> > > libpthread/linuxthreads/sysdeps/arm/pspinlock.c:21:
> > ./libpthread/linuxthreads/sysdeps/arm/pt-machine.h:36:
> > > warning: no previous prototype for 'testandset'
> > > /tmp/cczGDaGC.s: Assembler messages:
> > > /tmp/cczGDaGC.s:27: Error: selected processor does not support
> > > Thumb mode `swp r3,r3,[r0]'
> > > /tmp/cczGDaGC.s:46: Error: selected processor does not support
> > > Thumb mode `swp r3,r3,[r0]'
> > > make: *** [libpthread/linuxthreads/sysdeps/arm/pspinlock.os]
> > > Error 1
> > >
> > > NPTL:
> > > -----
> > >   CC libpthread/nptl/pthread_atfork.os
> > >   AS libpthread/nptl/sysdeps/unix/sysv/linux/arm/pt-vfork.os
> > >
> > libpthread/nptl/sysdeps/unix/sysv/linux/arm/../../../../../../../libc/sysdeps/linux/arm/vfork.S:
> > > Assembler messages:
> > >
> > libpthread/nptl/sysdeps/unix/sysv/linux/arm/../../../../../../../libc/sysdeps/linux/arm/vfork.S:72:
> > > Error: only SUBS PC, LR, #const allowed -- `sub pc,r0,#31'
> > >
> > libpthread/nptl/sysdeps/unix/sysv/linux/arm/../../../../../../../libc/sysdeps/linux/arm/vfork.S:74:
> > > Error: thumb conditional instruction should be in IT block --
> > > `strne r3,[r2,#-1044]'
> > > make: ***
> > > [libpthread/nptl/sysdeps/unix/sysv/linux/arm/pt-vfork.os] Error 1
> > >
> > > Extra CFLAGS :
> > > march=armv7-m -mthumb -Wl, -elf2flt -Wa, -march=armv7-m -Wa,
> > > -mthumb
> > >
> > > As I undestand thumb2 doesn't support swp instruction. But is
> > > there a way to avoid hardcoded swp instructions in threads code
> > > (spinlock implementation)?
> > >
> > Uclibc (still) lacks pthreads support on Cortex-M3.
> >
> > I'm attaching two patches:
> >  - implement testandset() for Cortex-M3.
> >  - Fix a bug in implementation of clone() for Cortex-M3.
> >
> > That should make pthreads work. Note also that we are building the
> > "linuxthreads.old" pthreads configuration.
> >
> >
> > Regards,
> >
> > Sergei Poselenov,
> > Emcraft Systems
> > > Regards.
> > > _______________________________________________
> > > uClibc mailing list
> > > uClibc at uclibc.org
> > > http://lists.busybox.net/mailman/listinfo/uclibc
> >
> >