fit for xen joshua whitehead getting u-boot paul skentzos ... fit for xen.pdfif a customer has an...

Getting U-Boot FIT for Xen

Xen Developers Summit 2015

Robbie VanVossenKarl ApsitePaul SkentzosJoshua Whitehead

where hardware and software design meet

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Presentation Outline

□ U-Boot□ FIT Image□ FIT Image Source File□ Loadables□ Building & Booting□ Benefits of Using FIT

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U-Boot

The Universal Bootloader

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U-Boot - History

□ Open Source Bootloader for embedded devices□ Originally 8xxROM□ 1999 - PPCBoot□ 2000 - Publicly released v0.4.1

□ Strictly for Power PC architecture□ 2002

□ Forked into a product called ARMBoot □ Renamed to Das U-Boot (Universal Bootloader) to reflect new

architecture support□ 2003 - Added MIPS32, MIPS64, Coldfire, Altera NIOS−32 □ 2008 - Added Flattened Image Tree support

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U-Boot - Features

□ Multiple loading methods□ TFTP, mmc devices, various flash devices, PXE, IDE, SATA, USB

□ Lots of supported architectures□ 68k, ARM, AVR32, Blackfin,

MicroBlaze, MIPS, Nios,PPC, and x86

□ Filesystem handling□ Including Cramfs, ext2, ext3, ext4,

FAT, FDOS, JFFS2, ReiserFS, UBIFS, and ZFS

□ Network handling□ ping, DHCP, TFTP

□ FDT handling□ Direct memory reads and writes

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FIT Image

Flattened Image Tree

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FIT Image - Introduction

□ Uses a tree-like structure□ Flexible, monolithic binary that includes everything for

booting□ Benefits

□ Image Hashing□ Multiple Configurations

□ FIT can not load more than one kernel

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FIT Image - Build Requirements

□ Utilities□ mkimage□ dtc - device tree compiler

□ Binaries□ Device Tree Binaries□ Kernels□ Optional ramdisks□ Optional Loadables (DornerWorks Contribution)

□ Image Source File (*.its)

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FIT Image - Generation

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Image Source File (*.its)

FIT Image (*.itb)

mkimage

Binaries (kernels, fdts, ramdisks)


Image Source File

FIT Configuration (Before our updates)

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Image Source File - Example.its

/dts-v1/;/ {

description = "Single Linux kernel and FDT blob";#address-cells = <1>;

images {

kernel@1 {description = "Vanilla Linux kernel";data = /incbin/("./vmlinux.bin.gz");type = "kernel";arch = "arm";os = "linux";compression = "gzip";load = <00000000>;entry = <00000000>;hash@1 {

algo = "crc32";};hash@2 {

algo = "sha1";};

};

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fdt@1 {description = "Flattened Device Tree

blob";data = /incbin/("./target.dtb");type = "flat_dt";arch = "arm";compression = "none";

load = <00700000>;hash@1 {

algo = "crc32";};hash@2 {

algo = "sha1";};

};};

fdt@2 {description = "Flattened Device Tree

blob";data = /incbin/("./target2.dtb");type = "flat_dt";arch = "arm";compression = "none";

load = <00700000>;};

};


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Image Source File - Example.its(cont)

ramdisk@1 {description = "ramdisk";data = /incbin/("./ramdisk");type = "ramdisk";arch = "arm";os = "linux";compression = "gzip";load = <00800000>;entry = <00800000>;hash@1 {

algo = "sha1";};

};};

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configurations {default = "conf@1";

conf@1 {description = "Linux kernel with FDT

blob";kernel = "kernel@1";fdt = "fdt@1";

};

conf@2 {description = "Linux kernel, fdt, &

ramdisk";kernel = "kernel@1";

ramdisk = “ramdisk@1”;fdt = "fdt@2";

};};

};


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Image Source File - Format

□ The image source file format is defined here:http://git.denx.de/?p=u-boot.git;a=blob_plain;f=doc/uImage.

FIT/source_file_format.txt;hb=HEAD

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http://git.denx.de/?p=u-boot.git;a=blob_plain;f=doc/uImage.FIT/source_file_format.txt;hb=HEAD




Loadables

New Configuration Property

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Loadables - Problem

□ To use a FIT Image to load a Xen system, we need a configuration for □ Xen kernel□ Xen Device Tree Blob (DTB)□ Dom0 kernel

□ The existing configuration properties:□ Allowed only one image per configuration□ Perform specific tasks and checks based on the type

□ The kernel property is the image that gets executed, so it needs to be the Xen kernel

□ The fdt property needs to be set to our DTB□ The ramdisk property can’t be used for our Dom0 kernel□ Therefore, we need a way to load a generic image (loadable) to a specific

location

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Loadables - Solution

□ Created a new configuration property□ Loadables - A list of image sub-nodes of any type

□ The loadables property doesn’t have any extra tasks or checks□ Multiple images□ Now there is a configuration property for the Dom0 Linux Kernel

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Updating U-Boot - U-Boot

□ Updated U-Boot to look for and handle the new loadables field□ Added bootm_find_loadables()/boot_get_loadable()

□ Refactored relevant functions for readability and simplicity□ Added tests for loadables□ U-Boot mainline at the tag v2015.07

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Updating U-Boot - mkimage

□ We modified mkimage to include the new loadables field.

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$ ./u-boot/tools/mkimage -f xen.its /tftpboot/xen.itbFIT description: Configuration to load a Xen Kernel... Default Configuration: 'config@1' Configuration 0 (config@1) Description: Xen 4.6.0-one loadable Kernel: xen_kernel@1 FDT: fdt@1 Loadables: linux_kernel@1 Configuration 1 (config@2) Description: Plain Linux Kernel: linux_kernel@1 FDT: fdt@2


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Loadables - xen.its

/dts-v1/;/ { description = "Configuration to load a Xen Kernel"; #address-cells = <1>;

images { xen_kernel@1 { description = "xen-4.6.0-unstable"; data = /incbin/("./xen"); type = "kernel"; arch = "arm"; os = "linux"; compression = "none"; load = <0xaea00000>; entry = <0xaea00000>; hash@1 { algo = "md5"; }; };

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fdt@1 { description = "Cubietruck Xen tree blob"; data = /incbin/("./xen.dtb"); type = "flat_dt"; arch = "arm"; compression = "none"; load = <0xaec00000>; hash@1 { algo = "md5"; }; };

fdt@2 { description = "Cubietruck tree blob"; data = /incbin/("./sun7i-a20-cubietruck.dtb"); type = "flat_dt"; arch = "arm"; compression = "none"; load = <0xaec00000>; hash@1 { algo = "md5"; }; };


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Loadables - xen.its (cont)

linux_kernel@1 { description = "Linux zImage"; data = /incbin/("./vmlinuz"); type = "kernel"; arch = "arm"; os = "linux"; compression = "none"; load = <0xaf600000>; entry = <0xaf600000>; hash@1 { algo = "md5"; }; }; };

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configurations { default = "config@1";

config@1 { description = "Xen 4.6.0-one loadable"; kernel = "xen_kernel@1"; fdt = "fdt@1"; loadables = "linux_kernel@1"; };

config@2 { description = "Plain Linux"; kernel = "linux_kernel@1"; fdt = "fdt@2"; };

};};


Example of how to build and boot from a FIT image

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Building & Booting


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Building the FIT Image

□ Build U-Boot with FIT support (CONFIG_FIT=y)□ Build images (Dom0 Kernel, Xen Kernel, and DTB) as usual□ Place images as specified in the image source file□ Build the output FIT image

$ mkimage -f xen.its xen.itb

□ Copy U-Boot to where it needs to be for your board□ Move the FIT image to where you will be booting from

□ We will use an SD card, with a boot partition, as an example

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Booting the FIT Image

□ Place the SD Card in your board□ Boot the board (Our example uses the cubietruck)□ Stop the U-Boot autoboot□ Load the FIT Image into Memory

sunxi# fatload mmc 0 0x80000000 /xen.itb

□ Boot configuration 1sunxi# bootm 0x80000000#config@1

□ U-Boot will then check the specified hashes for those images, move them to their proper load addresses, and boot into the specified kernel, Xen

□ Before booting a configuration, you can get information about your FIT image with the following commandsunxi# iminfo 0x80000000

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Booting - Example Output

sunxi# bootm 0x80000000#config@1## Loading kernel from FIT Image at 80000000 ... Using 'config@1' configuration Trying 'xen_kernel@1' kernel subimage Description: xen-4.6.0-unstable Type: Kernel Image Compression: uncompressed Data Start: 0x800000dc Data Size: 688912 Bytes = 672.8 KiB Architecture: ARM OS: Linux Load Address: 0xaea00000 Entry Point: 0xaea00000 Hash algo: md5 Hash value:

51424697da4d1523a8c87150c7cbad00 Verifying Hash Integrity ... md5+ OK## Loading fdt from FIT Image at 80000000 ... Using 'config@1' configuration

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Trying 'fdt@1' fdt subimage Description: Cubietruck Xen tree blob Type: Flat Device Tree Compression: uncompressed Data Start: 0x800a84d8 Data Size: 21940 Bytes = 21.4 KiB Architecture: ARM Hash algo: md5 Hash value:

3c27715e5c19226064186193e3f30bc4 Verifying Hash Integrity ... md5+ OK Loading fdt from 0x800a84d8 to 0xaec00000 Booting using the fdt blob at 0xaec00000## Loading loadables from FIT Image at

80000000 ... Trying 'linux_kernel@1' loadables subimage Description: Linux zImage Type: Kernel Image Compression: uncompressed Data Start: 0x800b3108 Data Size: 5247832 Bytes = 5 MiB


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Booting - Example Output (cont)

Architecture: ARM OS: Linux Load Address: 0xaf600000 Entry Point: 0xaf600000 Hash algo: md5 Hash value:

84c9630522c9737f6ded803177c967e8 Verifying Hash Integrity ... md5+ OK Loading loadables from 0x800b3108 to

0xaf600000 Loading Kernel Image ... OK Loading Device Tree to 4eff7000, end 4efff5b3

... OKCannot setup simplefb: node not found

Starting kernel ...

- UART enabled -- CPU 00000000 booting -- Xen starting in Hyp mode -- Zero BSS -

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- Setting up control registers -- Turning on paging -- Ready -Checking for initrd in /chosen[...]

Placing Xen at 0x00000000bfe00000-0x00000000c0000000

Xen heap: 000000009e000000-00000000ae000000 (65536 pages)

Dom heap: 458752 pagesLooking for UART console

/soc@01c00000/serial@01c28000 Xen 4.4.1-rc1(XEN) Xen version 4.4.1-rc1 (robertvanvossen@)

(arm-linux-gnueabihf-gcc (Ubuntu/Linaro 4.8.2-16ubuntu4) 4.8.2) debug=y Mon Jul 20 16:20:46 EDT 2015


Benefits of Using FIT

General and Xen Specific Benefits

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Benefits of Using FIT

□ Hashing Images□ Make sure they weren’t corrupted during transfer□ Make sure you have the correct images during production□ Cryptographic signatures for verified boot

□ Multiple configurations □ Could have different DTB’s for different passthrough configurations□ Could more easily boot into your linux kernel without Xen

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Benefits of Using FIT (cont)

□ Improved support□ Xilinx Zynq UltraScale+ MPSoC - Xen Zynq Distribution□ If a customer has an issue, they can provide their image source file□ Boot configurations could be maintained in builders

□ Potential future uses given further development:□ Memory mapped Co-processor images□ FPGA Images□ Databases□ DomU kernels

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Try It Yourself

If you want to duplicate our example for the CubieTruck, use the fit branch of our fork of the xen-arm-builder:

https://github.com/dornerworks/xen-arm-builder

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Questions?

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fit for xen joshua whitehead getting u-boot paul skentzos ... fit for xen.pdfif a customer has an...

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