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Alexey Brodkin cde947f5f5 uclibc: prevent rebuilding after installation to staging
Currently we configure uClibc to use kernel headers from "staging" folder with
KERNEL_HEADERS="$(STAGING_DIR)/usr/include". This path is added to include
search path of uClibc build system in Rules.mak "CFLAGS += -I$(KERNEL_HEADERS)".

At the same time on uClibc installation to "staging" we point to the same
location "$(STAGING_DIR)/usr" (headers effectively go in "usr/include").

So after every installation to "staging" dependences get touched (even though we
copy the same headers every time) and so we may see lots of sources in uClibc
get rebuilt.

This has 2 consequences:
1. Longer build time - becase even on ordinary buildroot build uClibc is built
twice. On "uclibc building" and on "uclibc installation to target".

2. Symbols in libuClibc built initially (that is later installed in
"staging/sysroot") are situated with different offset compared to second build
(later copied in "target"). This happens because as described above only part
of sources get rebuilt and then on final linkage object files are linked in
different order.

And (2) leads to problems on remote rebugging: gdbserver reports offsets that
correspond to pointless assembly in libuClibc on host.

Here's how it looks like.

Before this patch:
$ cd ~/br2_output/i586/target/lib
$ i586-buildroot-linux-uclibc-readelf -s libuClibc-0.9.33.2.so | grep kill
   423: 0000c42c    54 FUNC    GLOBAL DEFAULT    7 kill

$ cd ~/br2_output/i586/staging/lib
$ i586-buildroot-linux-uclibc-readelf -s libuClibc-0.9.33.2.so | grep kill
   423: 0000b518    54 FUNC    GLOBAL DEFAULT    7 kill

After this patch:
$ cd ~/br2_output/i586/target/lib
$ i586-buildroot-linux-uclibc-readelf -s libuClibc-0.9.33.2.so | grep kill
   423: 0000b518    54 FUNC    GLOBAL DEFAULT    7 kill

$ cd ~/br2_output/i586/staging/lib
$ i586-buildroot-linux-uclibc-readelf -s libuClibc-0.9.33.2.so | grep kill
   423: 0000b518    54 FUNC    GLOBAL DEFAULT    7 kill

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Noam Camus <noamc@ezchip.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
2014-06-17 20:40:23 +02:00
arch powerpc: add powerpc64 and powerpc64le support 2014-05-26 21:48:33 +02:00
board configs: bump zedboard to 2014.1 2014-06-09 12:09:20 +02:00
boot barebox: bump to version 2014.06.0 2014-06-07 09:24:06 +02:00
configs configs: bump zedboard to 2014.1 2014-06-09 12:09:20 +02:00
docs infra: consistently use double dollar signs inside inner-xxx-targets 2014-06-14 19:09:54 +02:00
fs infra: consistently use double dollar signs inside inner-xxx-targets 2014-06-14 19:09:54 +02:00
linux linux: bump default to version 3.15 2014-06-09 14:50:16 +02:00
package uclibc: prevent rebuilding after installation to staging 2014-06-17 20:40:23 +02:00
support classpath: Use generic check for host program 2014-06-14 19:55:28 +02:00
system systemd: needs kernel headers >= 3.10 2014-06-13 22:32:37 +02:00
toolchain toolchain/toolchain-buildroot: migrate to virtual package infrastructure 2014-06-14 19:10:13 +02:00
.defconfig buildroot: get rid of s390 support 2009-01-12 14:36:14 +00:00
.gitignore update gitignore 2013-05-04 12:41:55 +02:00
CHANGES Update for 2014.05 2014-05-31 09:52:49 +02:00
Config.in ccache: provide capability to do initial ccache setup 2014-06-14 20:00:35 +02:00
Config.in.legacy kernel headers: remove deprecated version 3.8 2014-06-13 22:27:39 +02:00
COPYING clarify license and fix website license link 2009-05-08 09:29:41 +02:00
Makefile Makefile: test if dot exists before using it in graph-depends 2014-06-13 14:59:52 +02:00
Makefile.legacy Makefile.legacy: fix recursive invocation with BUILDROOT_DL_DIR and _CONFIG 2014-02-11 08:14:57 +01:00
README docs: Move README file to root 2014-03-03 21:28:39 +01:00

To build and use the buildroot stuff, do the following:

1) run 'make menuconfig'
2) select the packages you wish to compile
3) run 'make'
4) wait while it compiles
5) Use your shiny new root filesystem. Depending on which sort of
    root filesystem you selected, you may want to loop mount it,
    chroot into it, nfs mount it on your target device, burn it
    to flash, or whatever is appropriate for your target system.

You do not need to be root to build or run buildroot.  Have fun!

Offline build:
==============

In order to do an offline-build (not connected to the net), fetch all
selected source by issuing a
$ make source

before you disconnect.
If your build-host is never connected, then you have to copy buildroot
and your toplevel .config to a machine that has an internet-connection
and issue "make source" there, then copy the content of your dl/ dir to
the build-host.

Building out-of-tree:
=====================

Buildroot supports building out of tree with a syntax similar
to the Linux kernel. To use it, add O=<directory> to the
make command line, E.G.:

$ make O=/tmp/build

And all the output files (including .config) will be located under /tmp/build.

More finegrained configuration:
===============================

You can specify a config-file for uClibc:
$ make UCLIBC_CONFIG_FILE=/my/uClibc.config

And you can specify a config-file for busybox:
$ make BUSYBOX_CONFIG_FILE=/my/busybox.config

To use a non-standard host-compiler (if you do not have 'gcc'),
make sure that the compiler is in your PATH and that the library paths are
setup properly, if your compiler is built dynamically:
$ make HOSTCC=gcc-4.3.orig HOSTCXX=gcc-4.3-mine

Depending on your configuration, there are some targets you can use to
use menuconfig of certain packages. This includes:
$ make HOSTCC=gcc-4.3 linux-menuconfig
$ make HOSTCC=gcc-4.3 uclibc-menuconfig
$ make HOSTCC=gcc-4.3 busybox-menuconfig

Please feed suggestions, bug reports, insults, and bribes back to the
buildroot mailing list: buildroot@buildroot.org