Why arm-linux-gnueabi-gcc and not arm-none-eabi-gcc when compiling Linux kernel and uBoot?

9
votes

I have some experience compiling bare metal code for ARM cortex-m devices as well as the Linux kernel, uBoot, and applications for the Beaglebone Black (BBB) (more featured ARM with MMU, for those living under a rock). It makes sense to me that the cortex-m code should be compiled using arm-none-eabi-gcc (as there is no OS) and the application code for the BBB should be compiled with arm-linux-gnueabi-gcc (as there is an OS, for which system calls can be made and program loaders and shared objects can be utilized).

What I don't understand is why uBoot and the kernel also should be compiled with arm-linux-gnueabi-gcc. In my mind, uBoot at least, is a bare metal program with no fancy OS to account for. This has been bugging me for sometime, but I can't find an answer. Is there anyone out there that can enlighten me?

1
clinuxgccu-bootabi
Where did you learn this "uBoot [sic] and the kernel also should be compiled with arm-linux-gnueabi-gcc"? I've seen U-Boot and the Linux kernel compiled with the same toolchain (e.g. in Buildroot) presumably because of convenience. But I typically use a baremetal toolchain for bootloaders such as U-Boot (i.e. I build two toolchains). – sawdust
I just assumed from examples such as this. Are you saying that uBoot can actually be compiled with either? What about the kernel? – Joshua DeWeese
When compiling .c into .o, the ABI you choose affects which registers are used for parameters, stack-layout etc. When linking the .o into an executable, the ABI have a default linker script and helper objects. But both the kernel and probably u-boot provides their own linker scripts etc, so the ABI for this step is not so important – Stian Skjelstad
This question has been answered here : stackoverflow.com/questions/38956680/… – Anna Lyons
@JoshuaDeWeese processors.ti.wiki.com EOL. Link dead. Archive here. – Darren Ng

1 Answers

-2
votes

U-Boot was designed to mirror the Linux design philosophy as much as possible. It uses the same configuration system, general directory structure, etc. It shares some APIs with Linux - see the include/linux directory. As the comments above mention, the ABI compatibility doesn't matter at this point, but using a Linux compiler isn't philosophically inappropriate for U-Boot.