Add a short README file describing what the bootwrapper is and how to run it. Signed-off-by: Peter Maydell <peter.maydell at linaro.org> --- README.txt | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 README.txt diff --git a/README.txt b/README.txt new file mode 100644 index 0000000..d0277ee --- /dev/null +++ b/README.txt @@ -0,0 +1,73 @@ +boot-wrapper: Start Linux kernels under ARM Fast Models + +The boot-wrapper is a fairly simple implementation of a boot loader +intended to run under an ARM Fast Model and boot Linux. + +License +======= + +The boot-wrapper is generally under a 3 clause BSD license +(see LICENSE.txt for details). Note that some source files +are under similar but compatible licenses. In particular +libfdt is dual-license GPL/2-clause-BSD. + +Compilation +=========== + +The expected method of building is to cross-compile on an +x86 box. You'll need an ARM cross-compiler. On Ubuntu you +can get this by installing the packages: + gcc-4.6-arm-linux-gnueabi binutils-arm-linux-gnueabi + libc6-armel-cross linux-libc-dev-armel-cross gcc-arm-linux-gnueabi + libc6-dev-armel-cross cpp-arm-linux-gnueabi + +The boot-wrapper can be compiled in two ways: + (1) as a small standalone binary which uses the model's semihosting + ABI to load a kernel (and optionally initrd and flattened device tree) + when you run the model + (2) with a specific kernel and initrd compiled into the binary; + this is less flexible but may be useful in some situations + +For case (1) you can just run: + make CROSS_COMPILE=arm-linux-gnueabi- semi +which will build "linux-system-semi.axf". +(As with a Linux kernel cross-compile, the CROSS_COMPILE +variable is set to the prefix of the cross toolchain. +"arm-linux-gnueabi-" matches the prefix used by the Ubuntu +cross toolchain.) + +For case (2) you'll need a Linux kernel tree to hand; the +boot-wrapper makefile will automatically look into it to +extract the kernel. By default this tree is assumed to be in +"../linux-kvm-arm". Assuming you have that tree set up and +have built a kernel in it, you can run: + make CROSS_COMPILE=arm-linux-gnueabi- +which will build "linux-system.axf". + +You can configure the makefile system by copying config-default.mk +to config.mk and editing it. This is only likely to be useful for +case (2); see the comments in config-default.mk for more information. + +Running +======= + +To run a model with a linux-system-semi.axf: + +RTSM_VE_Cortex-A15x1 linux-system-semi.axf -C cluster.cpu0.semihosting-cmd_line="--kernel /path/to/zImage [--initrd /path/to/initrd] [--fdt /path/to/fdt] [-- kernel command line arguments]" + +The paths to the kernel, initrd and fdt should all be host filesystem +paths. The initrd and fdt are both optional. Any text following '--' +is passed to the kernel as its command line; this is also optional. + +You may also want to pass other options to the model (for instance +to enable networking); these are not described here. See the Fast +Models documentation for more information. + +Running a linux-system.axf is the same, except that since all +the files are built in there's no need to pass a command line: + +RTSM_VE_Cortex-A15x1 linux-system.axf + +Passing a command line to linux-system.axf is allowed, and any +kernel/initrd/fdt/commandline specified will override the compiled-in +version. -- 1.7.9.5
