[gentoo-user] How to build kernel with old binutils?

[Grant Edwards]

I regularly need to build old Linux kernels (as far back as 2.6), and
have a variety of older versions of gcc installed and a shell script
that knows what versions of gcc to use for what kernel versions. Using
an old version of GCC is simple: you just specify it on the command
line when doing the make:

$ cd linux-3.whatever
$ make distclean
$ make defconfig
$ make GCC=/usr/bin/gcc-4.3.6 modules

After some recent updates, I now get an 'ld' failure on some old
kernel buils. From what I've read it seems that I now need to also use
older binutils versions, and that's got me stumped. I've tried adding
LD=/path/to/ld to the make, but that appears to be ignored.

Can somebody give a clue how to specify the binutils to be used when
building a Linux kernel?

Thanks...

--
Grant

[Alan J. Wylie]

Post by Grant Edwards
Can somebody give a clue how to specify the binutils to be used when
building a Linux kernel?

$ man binutils-config

The binutils-config script allows you to switch between different
versions of binutils when you have installed multiple copies (see
USE=multislot). It also allows you to manage multiple cross-compiling
targets simultaneously.

$ binutils-config --list-profiles
[1] arm-none-eabi-2.38 *
[2] x86_64-pc-linux-gnu-2.38 *

[Grant Edwards]

Post by Alan J. Wylie

Post by Grant Edwards
Can somebody give a clue how to specify the binutils to be used when
building a Linux kernel?

$ man binutils-config
The binutils-config script allows you to switch between different
versions of binutils when you have installed multiple copies (see
USE=multislot). It also allows you to manage multiple cross-compiling
targets simultaneously.

AFAICT, that changes the binutils configuraiton for the entire
system. That's not what I want to do. I want to use specific binutils
versions for specific make invocations. [Similar to the way can for
gcc with "make GCC=/usr/bin/gcc-whatever".] Is there an option I
missed that just changes the configuration only for the current shell
session?

[Grant Edwards]

Post by Grant Edwards

Post by Alan J. Wylie
$ man binutils-config
[...]

AFAICT, that changes the binutils configuraiton for the entire
system. That's not what I want to do. I want to use specific binutils
versions for specific make invocations. [...]

Perhaps, pretend you're cross compiling? Perhaps you sort of are,
anyway, even if just for other package versions on the same
architecture?
Might "crossdev" help?
https://wiki.gentoo.org/wiki/Embedded_Handbook/General/Creating_a_cross-compiler
$ crossdev --help
Usage: crossdev [options] --target TARGET

Thanks!

That looks promising. I was somewhat aware of crossdev, but it hadn't
occured to me to use it to to generate native toolchains with various
versions of gcc/binutils. In my case, I wouldn't need any libc at all,
but that shouldn't be a big problem.

--
Grant