Difference between revisions of "EBC Exercise 08a Cross-Compiling"

From eLinux.org
Jump to: navigation, search
m (Cross-compiling Hello World: Added ARM_TOOLCHAIN_PATH)
m (Cross-compiling Hello World)
(26 intermediate revisions by 4 users not shown)
Line 1: Line 1:
 
[[Category:ECE497]]
 
[[Category:ECE497]]
 
[[Category: BeagleBoard]]
 
[[Category: BeagleBoard]]
 +
{{YoderHead}}
  
This class is about developing software for embedded Linux. So far we have been doing all of our development on the Beagle. This works well for small (and not so small) programs. However, we are now moving into kernel development and that's best done on a more powerful host computer. [[EBC_Exercise_01_Using_bitbake_for_Kernel_and_U-boot | Here]] you learned how to download and install the cross-compilers and the source for kernel and u-boot. Now we'll use those tools.
+
This class is about developing software for embedded Linux. So far we have been doing all of our development on the Beagle. This works well for small (and not so small) programs. However, we are now moving into kernel development and that's best done on a more powerful host computer. In [[EBC Exercise 08 Installing Development Tools]] you learned how to download and install the cross-compilers and the source for kernel and u-boot. Now we'll use those tools.
 
+
First we'll check everything by compiling the Hello World program, then we'll try the kernel and u-boot.
+
  
 
== Cross-compiling Hello World ==
 
== Cross-compiling Hello World ==
 +
This shows how to cross-compile with compiler loaded with
 +
 +
host$ '''sudo apt-get install -y git lzop gcc-arm-linux-gnueabi uboot-mkimage'''
  
 
Listing 2-4 on page 29 of the text is an embedded version of Hello World. If you've set up your git repository you will find it in '''helloWorld.c''' when you do a''' git pull'''.  Compile and run it on your host to be sure it works.
 
Listing 2-4 on page 29 of the text is an embedded version of Hello World. If you've set up your git repository you will find it in '''helloWorld.c''' when you do a''' git pull'''.  Compile and run it on your host to be sure it works.
Line 17: Line 19:
 
  This address (0x601020) is in our data section
 
  This address (0x601020) is in our data section
  
Now that you know it's working, let's cross compile it. First set the paths to find the cross-compilers. Put the following in a file, call it ~/.oe/'''crossCompileEnv.sh'''. Make sure the path is correct for your system. This is for a 32-bit linux.  
+
Now that you know it's working, let's cross compile it. First set the paths to find the cross-compiler. Put the following in a file, call it ~/.oe/'''crossCompile.sh'''.
  
# add cross tools to your path
 
export ARM_TOOLCHAIN_PATH=~/BeagleBoard/oe/build/tmp-angstrom_2010_x-eglibc/sysroots/i686-linux/usr/bin/armv7a-angstrom-linux-gnueabi
 
PATH=$PATH:$ARM_TOOLCHAIN_PATH/..
 
PATH=$ARM_TOOLCHAIN_PATH:$PATH 
 
 
  export ARCH=arm
 
  export ARCH=arm
  export CROSS_COMPILE=arm-angstrom-linux-gnueabi-
+
  export CROSS_COMPILE=arm-linux-gnueabi-
 
+
Here it is for 64-bit
+
 
+
# add cross tools to your path
+
export ARM_TOOLCHAIN_PATH=~/BeagleBoard/oe/build/tmp-angstrom_2010_x-eglibc/sysroots/x86_64-linux/usr/bin/armv7a-angstrom-linux-gnueabi
+
PATH=$PATH:$ARM_TOOLCHAIN_PATH/..
+
PATH=$ARM_TOOLCHAIN_PATH:$PATH 
+
export ARCH=arm
+
export CROSS_COMPILE=arm-angstrom-linux-gnueabi-
+
  
 
Now ''source'' the file and compile again. (Note: you only have to source once per terminal session.)
 
Now ''source'' the file and compile again. (Note: you only have to source once per terminal session.)
Line 52: Line 41:
 
The '''scp''' copies a.out to the beagle and the '''ssh''' runs the a.out on the beagle. Notice the address are very different from the host version.
 
The '''scp''' copies a.out to the beagle and the '''ssh''' runs the a.out on the beagle. Notice the address are very different from the host version.
  
== Finding the Kernel and Installing It ==
+
{{YoderFoot}}
 
+
After doing [[EBC_Exercise_01_Using_bitbake_for_Kernel_and_U-boot#Finding_the_Correct_Kernel | this]] exercise you have a Beagle kernel on your host computer. Let's see if it works.
+
 
+
Once compiled the kernel is put in a file called '''uImage'''.  You may have seen it in the FAT partition on your SD card.  Let's find it on your host. One way to find it is
+
 
+
host$ '''cd ~/BeagleBoard/oe'''
+
host$ '''find . -name "*uImage*" | grep 2.6.32 | grep boot'''
+
 
+
We are looking for uImage, but we only want the 2.6.32 version.  The last grep file the file in the '''boot''' directory. Several lines are printed, but the one I'm interested in is:
+
''./build/tmp-angstrom_2010_x-eglibc/work/beagleboard-angstrom-linux-gnueabi/linux-omap-psp-2.6.32-r110b+gitr5fc29e7b2a76a64a739f857858ef0b98294aa155/git''/arch/arm/boot/uImage
+
 
+
The first part of the path (in italics) is the path to the kernel.  Check it out.
+
 
+
host$ '''cd build/tmp-angstrom_2010_x-eglibc/work/beagleboard-angstrom-linux-gnueabi/linux-omap-psp-2.6.32-r110b+gitr5fc29e7b2a76a64a739f857858ef0b98294aa155/git'''
+
host$ '''ls -F'''
+
arch/          drivers/  Kbuild      modules.order  samples/    usr/
+
block/          firmware/  kernel/      Module.symvers  scripts/    virt/
+
COPYING        fs/        lib/        net/            security/  vmlinux*
+
CREDITS        include/  MAINTAINERS  patches/        sound/      vmlinux.o
+
crypto/        init/      Makefile    README          System.map
+
Documentation/  ipc/      mm/          REPORTING-BUGS  tools/
+
 
+
We'll be learning what's in many of these over the next couple of weeks.  Remember this location.  Let's find uImage.
+
 
+
host$ '''cd arch/arm/boot; ls -shF'''
+
total 13M
+
4.0K bootp/      6.3M Image*      4.0K Makefile  3.0M zImage*
+
4.0K compressed/  4.0K install.sh  3.0M uImage
+
host$ '''ls -l uImage'''
+
-rw-r--r-- 1 beagle beagle 3144300 2011-12-08 01:02 uImage
+
 
+
It should have the date that you did the bitbake.  Let's see if it runs on the Beagle
+
host$ '''scp uImage root@beagle:.'''
+
host$ '''ssh root@beagle'''
+
beagle$ '''cd /boot; ls -F'''
+
total 18M
+
4.0K MLO@
+
372K Module.symvers-2.6.32
+
1.4M System.map-2.6.32
+
  80K config-2.6.32
+
4.0K u-boot.bin@
+
    0 uImage@
+
3.1M uImage-2.6.32
+
8.9M vmlinux-2.6.32
+
beagle$ '''ls -l uImage'''
+
lrwxrwxrwx 1 www-data www-data 13 May 12  2011 uImage -> uImage-2.6.32
+
 
+
So the uImage that is there is a symbolic link to '''uImage-2.6.32'''.  Let's save the working uImage in a difference file and copy our new uImage in.
+
 
+
beagle$ '''mv uImage-2.6.32 uImage-2.6.32.orig'''
+
beagle$ '''mv ~/uImage uImage-2.6.32'''
+
 
+
And then reboot.
+
beagle$ '''shutdown -r now'''
+
 
+
After a couple of minutes your should be back and running again.  Check and see if you are really running the new kernel.
+
beagle$ '''uname -a'''
+
Linux beagleboard 2.6.32 #3 PREEMPT Thu Dec 8 01:02:13 EST 2011 armv7l GNU/Linux
+
 
+
It worked! That's the date I compiled mine on.
+
 
+
== Installing a New U-boot ==
+
 
+
While we're at it, let's install a new U-boot.  Note:  The new U-boot isn't working for me.
+
 
+
host$ '''cd ~/BeagleBoard/oe/build/tmp-angstrom_2010_x-eglibc/work/beagleboard-angstrom-linux-gnueabi/'''
+
host$ '''ls -F'''
+
linux-3.0.9-r110a/
+
linux-omap-psp-2.6.32-r110b+gitr5fc29e7b2a76a64a739f857858ef0b98294aa155/
+
shadow-4.1.4.3-r5/
+
u-boot-2011.09-r4/
+
 
+
There's the U-boot directory.
+
 
+
host$ cd u-boot-2011.09-r4/git/; ls -F
+
api/        COPYING    fs/          mkconfig*    post/            tools/
+
arch/      CREDITS    include/    mmc_spl/      README          u-boot*
+
board/      disk/      lib/        nand_spl/    rules.mk        '''u-boot.bin'''
+
boards.cfg  doc/      MAINTAINERS  net/          snapshot.commit  u-boot.lds
+
common/    drivers/  MAKEALL*    onenand_ipl/  spl/            u-boot.map
+
config.mk  examples/  Makefile    patches/      System.map      u-boot.srec
+
 
+
The file we want is right on the top level.
+
 
+
host$ '''scp u-boot.bin root@beagle:.'''
+
host$ '''ssh -X root@beagle'''
+
beagle$ '''cd /media/mmcblk0p1/; ls -F'''
+
MLO*        u-boot.bin.broken*  uEnv.txt*
+
U-BOOT.BIN*  UIMAGE*            uEnv/
+
 
+
Here we've changed to the FAT partition which is where u-boot lives.  Back it up and install the new one.
+
 
+
beagle$ '''mv U-BOOT-BIN u-boot-bin.orig'''
+
beagle$ '''mv ~/.u-boot-bin .'''
+
beagle$ '''shutdown -r now'''
+
 
+
You should now see the new u-boot running.  However I was unable to get the 2.6.32 kernel to boot.
+
 
+
== Compile via make ==
+
 
+
When you use bitbake it sets up all the paths to use the correct cross compilers.  You can also build the kernel or u-boot by using '''make''' if you set the paths like we did above. 
+
 
+
If you haven't already, ''source'' the file and ''cd'' to the kernel directory and try a ''make''.
+
 
+
host$ '''source ~/.oe/crossCompileEnv.sh'''
+
host$ '''cd ~/BeagleBoard/oe/build/tmp-angstrom_2008_1/work/beagleboard-angstrom-linux-gnueabi/linux-omap-psp-2.6.32-r88+gitra6bad4464f985fdd3bed72e1b82dcbfc004d7869/git'''
+
host$ '''make xconfig'''
+
 
+
([[EBC Exercise 13 Configuring the Kernel]] has details on configuring the kernel.)
+
 
+
To make the kernel run
+
 
+
host$ '''make uImage'''
+
 
+
Now, follow the instructions above to install your freshly compiled kernel.
+

Revision as of 20:01, 29 October 2012

thumb‎ Embedded Linux Class by Mark A. Yoder


This class is about developing software for embedded Linux. So far we have been doing all of our development on the Beagle. This works well for small (and not so small) programs. However, we are now moving into kernel development and that's best done on a more powerful host computer. In EBC Exercise 08 Installing Development Tools you learned how to download and install the cross-compilers and the source for kernel and u-boot. Now we'll use those tools.

Cross-compiling Hello World

This shows how to cross-compile with compiler loaded with

host$ sudo apt-get install -y git lzop gcc-arm-linux-gnueabi uboot-mkimage

Listing 2-4 on page 29 of the text is an embedded version of Hello World. If you've set up your git repository you will find it in helloWorld.c when you do a git pull. Compile and run it on your host to be sure it works.

host$ gcc helloWorld.c
host$ ./a.out
Hello, World! Main is executing at 0x400524
This address (0x7fff8260bdf8) is in our stack frame
This address (0x601038) is in our bss section
This address (0x601020) is in our data section

Now that you know it's working, let's cross compile it. First set the paths to find the cross-compiler. Put the following in a file, call it ~/.oe/crossCompile.sh.

export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabi-

Now source the file and compile again. (Note: you only have to source once per terminal session.)

host$ source ~/.oe/crossCompileEnv.sh
host$ ${CROSS_COMPILE}gcc helloWorld.c
host$ file a.out
a.out: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, not stripped

The file command tells what's in the file. In this case we have an ARM executable. Success! Now copy to your Beagle and run

host$ scp a.out root@beagle:.
host$ ssh root@beagle ./a.out
Hello, World! Main is executing at 0x8374
This address (0xbeb32d4c) is in our stack frame
This address (0x10650) is in our bss section
This address (0x10648) is in our data section

The scp copies a.out to the beagle and the ssh runs the a.out on the beagle. Notice the address are very different from the host version.




thumb‎ Embedded Linux Class by Mark A. Yoder