# riscv-linux

**Repository Path**: blue_17/riscv-linux

## Basic Information

- **Project Name**: riscv-linux
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2019-12-09
- **Last Updated**: 2020-12-19

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Linux/RISC-V

This is a port of Linux kernel for the [RISC-V](http://riscv.org/)
instruction set architecture.
Development is currently based on the
[4.6 longterm branch](https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?h=linux-4.6.y).


## Obtaining kernel sources

### Master

Overlay the `riscv` architecture-specific subtree onto an upstream release:

        $ curl -L https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.6.2.tar.xz | tar -xJ
        $ cd linux-4.6.2
        $ git init
        $ git remote add -t master origin https://github.com/lowrisc/riscv-linux.git
        $ git fetch
        $ git checkout -f -t origin/master
        # lowRISC-specific hack for enabling power pin for SD card
        $ patch -p1 < spi_sd_power_hack.patch

Note that the `-t <branch>` option minimizes the history fetched.
To add another branch:

        $ git remote set-branches --add origin <branch>
        $ git fetch

### Full kernel source trees

For convenience, full kernel source trees are maintained on separate
branches tracking
[linux-stable](https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git):

* `linux-4.6.y-riscv`
* `linux-3.14.y-riscv` (historical)

## Building the kernel image

1. Create kernel configuration based on architecture defaults:

        $ make ARCH=riscv defconfig

1. Optionally edit the configuration via an ncurses interface:

        $ make ARCH=riscv menuconfig

1. Build the uncompressed kernel image:

        $ make -j4 ARCH=riscv vmlinux

1. Boot the kernel in the functional simulator, optionally specifying a
   raw disk image for the root filesystem:

        $ spike +disk=path/to/root.img bbl vmlinux

   `bbl` (the Berkeley Boot Loader) is available from the
   [riscv-pk](https://github.com/riscv/riscv-pk) repository.

## Exporting kernel headers

The `riscv-gnu-toolchain` repository includes a copy of the kernel header files.
If the userspace API has changed, export the updated headers to the
`riscv-gnu-toolchain` source directory:

    $ make ARCH=riscv headers_check
    $ make ARCH=riscv INSTALL_HDR_PATH=path/to/riscv-gnu-toolchain/linux-headers headers_install

Rebuild `riscv64-unknown-linux-gnu-gcc` with the `linux` target:

    $ cd path/to/riscv-gnu-toolchain
    $ make linux