failure on linux compilation

[allencho1222]

I followed the lowRISC guide to compile linux for untethered version:

#set up the RISCV environment variables
cd $TOP/riscv-tools
curl https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.14.41.tar.xz \
  | tar -xJ
cd linux-3.14.41
git init
git remote add origin https://github.com/lowrisc/riscv-linux.git
git fetch
git checkout -f -t origin/untether-v0.2
make ARCH=riscv defconfig
make ARCH=riscv -j vmlinux

And I got following errors : (I enter the 'sudo make ARCH=riscv -j8 vmlinux')

make: riscv64-unknown-linux-gnu-gcc: Command not found CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CC scripts/mod/empty.o /bin/sh: 1: riscv64-unknown-linux-gnu-gcc: not found scripts/Makefile.build:308: recipe for target 'scripts/mod/empty.o' failed make[2]: [scripts/mod/empty.o] Error 127 make[2]: Waiting for unfinished jobs.... CC scripts/mod/devicetable-offsets.s /bin/sh: 1: riscv64-unknown-linux-gnu-gcc: not found scripts/Makefile.build:204: recipe for target 'scripts/mod/devicetable-offsets.s' failed make[2]: [scripts/mod/devicetable-offsets.s] Error 127 scripts/Makefile.build:455: recipe for target 'scripts/mod' failed make[1]: [scripts/mod] Error 2 Makefile:527: recipe for target 'scripts' failed make: *** [scripts] Error 2

The error message says that it can't find 'riscv64-unknown-linux-gnu-gcc'. However, I already installed the riscv tool chain including riscv64-unknown-linux-gnu-gcc, even for newlib version. In addition, I added the path of 'riscv64-unknown-linux-gnu-gcc into PATH env variable, and 'which' command shows where it is.

Furthermore, I tried same thing by using other commands such as including CROSS_COMPILE=riscv64-unknown-linux-gnu-'. But, all fails.

[seldridge]

make: riscv64-unknown-linux-gnu-gcc: Command not found

You do not have riscv64-unknown-linux-gnu-gcc on your path. See the instructions for building a Linux toolchain here: https://github.com/riscv/riscv-gnu-toolchain#installation-linux. Note: after you build that, a make install will install that in $RISCV/bin (assuming that you set up your $RISCV environment variable). You will then have both a newlib (*-unknown-elf-*) and linux (*-unknown-linux-gnu-*) toolchain available. The latter is needed to build the Linux kernel.

Also, no need to use sudo for this. That will only complicate things as it won't find things on your user $PATH...

[allencho1222]

@seldridge Thks for replying. But as you can see from pictures, there's no problem on PATH variable. riscv64-unknown-linux-gnu-gcc works correctly as you can see from a third picture.

[seldridge]

Your user $PATH will not have the same path as the root user. When you run sudo, you're running in a root shell and will have the $PATH of root. As an example, running sh -c 'echo $PATH' as me and with sudo will produce two different paths. My user path has my local install of the toolchain in /opt/riscv/bin while the root path does not:

> sh -c 'echo $PATH'
/home/se/usr/bin:/home/se/usr/stow/anaconda3/bin/:/home/se/perl5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/opt/riscv/bin:/usr/local/texlive/2016/bin/x86_64-linux:
> sudo sh -c 'echo $PATH'
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin

I think that you can build the kernel without sudo. Can you try a make ARCH=riscv -j vmlinux without sudo?

Note: running sudo echo $PATH will show your user path as bash will expand $PATH before the command is executed.

Edit: first picture didn't load for me. I can see that you're running without sudo and it's going.

[seldridge]

You may need to explicitly specify the build target as vmlinux per the lowRISC guide. I haven't done this in a while, but can test locally (at some point).

[allencho1222]

@seldridge running without sudo command shows me a problem on following :

[jim-wilson]

The fact that earlier builds were built with sudo means that your build tree has files owned by root, and you will not be able to overwrite them without sudo. You should not need sudo to do a build. I'd suggest deleting your current linux build tree very carefully using sudo rm -rf, and starting a new one without sudo.

[allencho1222]

It seems that the problem was 'sudo' command like what @jim-wilson said. However, after make new copy of linux, I met following new errors:

the riscv64-unknown-gnu-gcc has no 'm64' option.

[jim-wilson]

Looks like you might be accidentally building an x86 kernel. Try looking at the .config file in the linux build tree. It should have a CONFIG_RISCV=y line near the top. If you see any other architecture, x86 in particular, then it wasn't configured correctly.

[allencho1222]

@jim-wilson CONFIG_RISCV is correctly set to 'y'. But, I still have problems like above.

• It seems that lowrisc uses lower version of GCC compiler. I need to get their version from their repository.

[jim-wilson]

You should check to see if you have any environment variables set that could affect the compiler. Maybe you have a global definition of CFLAGS that adds -m64 for instance.

[Jeremygu]

I encountered the same error. riscv64-unknown-linux-gnu-gcc: error: unrecognized command line option '-m64' riscv64-unknown-linux-gnu-gcc: error: unrecognized command line option '-msoft-float'

This is because we use the old branchuntether-v0.2 from lowrisc(https://github.com/lowrisc/riscv-linux.git). It is old now. I can find the CFLAG -m64 (and -msoft-float) by the following command: jeremy@ubuntu:~/workspace/riscv/linux-3.14.41$ git grep -- "FLAGS"

The GCC flags have changed for tracking upstream (see https://github.com/riscv/riscv-linux/issues/56). The solution I choose is to newly build linux kernel 4.18.y (4.18.2) together with riscv-linux4.18 [https://github.com/riscv/riscv-linux/tree/riscv-linux-4.18]. Unzip the downloaded linux-4.18.2.tar.xz file, then use the following commands:

$cd linux-4.18.2 $git init $git remote add origin https://github.com/riscv/riscv-linux.git $git fetch $git checkout -f -t origin/riscv-linux-4.18 $make ARCH=riscv defconfig $make -j8 ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu-

Done. A vmlinux file will be generated in the current directory. PS: here [https://github.com/riscv/riscv-tools/issues/163] is a reference about CROSS_COMPILE=.

[palmer-dabbelt]

I'm closing this as it's not a riscv-tools issue.