关于各分支功能介绍 About each branch feature

[fanghuaqi]

请关注最新的issue评论，这里的文字说明可能不是最新版本，以具体代码为准

请注意 本issue与其他issue会经常更新，请点击上面的 edited 来获知最新的修改的变更

Note

点击这里还可以看到更多 Nuclei Linux SDK使用的各种技巧和场景的文章，持续不断更新完善中。

Caution

• 使用老版本的Linux SDK分支，例如v2或者更早的版本，均需要注意freeloader里面之前CC_CTRL配置的时候是直接写1的（主要是PF_NO_WB(PFNWB)这个位域默认值被改写），但是这种写法可能导致Linux启动或者运行出现问题(stress-ng hangup)或者其他莫名其妙的hang死，应该是只修改CC_CTRL.CC_EN位域就行, 同时还有很多freeloader相关的修改也需要注意，这些在新版本v3分支上都已经修改了，详细参见 关于各分支功能介绍 About each branch feature #2 (comment)
• 使用老版本的Linux SDK，还可能遇到因为buildroot config里面配置的toolchain下载地址是老的URL，但是由于网站升级下载链接发生变化，导致构建失败，需要按照 关于各分支功能介绍 About each branch feature #2 (comment) 这里步骤进行类似修复

中文介绍

Note

• 源码获取请点击: 如何下载最新的源码(无git) How to download latest source code without git #4
• 一些常见问题，请参见 Common Questions 常见问题 #12

截止到2026.05.14起更新的代码，分支特性说明如下：

• 2026.05.14 更新v3分支上默认工具链从2025.02到2025.10版本，以修复gcc工具链的严重bug，详细参见 关于各分支功能介绍 About each branch feature #2 (comment)
• 2025.11.12, 同步内网最新的v2/v3分支最新的代码，可以点击进入对应的分支看看commit history
• 2025.09.10, 更新了_v3_*分支下的代码，为evalsoc配置新增了PMUv2和XEC以太网支持，更新了freeloader和OpenSBI以适配新的CPU特性（如TLB控制和预取），同时修复了编译告警、64位地址错误并优化了CI流程。关于各分支功能介绍 About each branch feature #2 (comment)
• 2025.05.19, 增加_v3系列分支，切换到2025.02-gcc14工具链，未来弃用其他分支: 关于各分支功能介绍 About each branch feature #2 (comment)
• 2024.12.06: 关于各分支功能介绍 About each branch feature #2 (comment)

主要支持如下SoC:

• demosoc: 比较早版本的评估用的SoC，不带有CPU IREGION特性，已经弃用，不再支持。
• evalsoc: 目前最新的评估用的SoC，带CPU IREGION特性，演进了两个版本
  • evalsoc v1: DDR Base为0xA0000000, 默认提供的FPGA Soft CPU Core Frequency 通常是 100MHz 或者 50Mhz，不再支持
  • evalsoc v2: DDR Base为0x80000000, 默认提供的FPGA Soft CPU Core Frequency 通常是 50Mhz, 2023.07引入作为evalsoc v1的替代。
  • 最新的 900 评估bitstream都是采用的evalsoc v2

分支说明

请注意：切换分支或者切换启动模式(sd/flash), 需要清理 work目录，删掉或者重命名，且切换分支的时候，需要同时更新submodule的代码

请注意: 如果你打算在你自己的SOC上bringup Linux环境，请先阅读我们准备好的bringup建议 #21

目前活跃开发的分支为 dev_nuclei_5.10/6.1/6.6/6.9/6.12_v3: 主要针对最新的900 CPU的FPGA evalsoc进行适配和优化。

提醒: 后续我们将只积极维护 _v3 分支，其他分支不再积极维护，其他特性功能我们也将逐步迁移到 2025.10-gcc14的工具链上开发

提醒: 目前 _v3 分支使用的是开发中的预编译好的2025.10 gcc14 glibc工具链，工具链的信息记录在 buildroot_initramfs_*_config文件中。

提醒: 计划使用 dev_nuclei_next / dev_nuclei_5.10分支的， 建议直接使用 dev_nuclei_5.10_v3 分支

提醒: 关于默认的CPU/Peripheral/Timer频率以选中的SoC中对应的dts(如nuclei_rv64imafdc.dts)和build.mk配置为准。

提醒: 请根据你当前拿到的bitstream的CPU版本以及CPU主频来选择分支，切换到对应分支，并确保代码是最新的，然后检查并修改对应的dts或者build.mk来满足你的bitstream的要求，再进行代码的构建。

以下是各个分支的情况说明

Note

下面这些分支是活跃维护分支

• 不要使用 2025.02 工具链，上面有已知的严重bug，参见 Nuclei RISC-V Toolchain Known Issues riscv-mcu/riscv-gnu-toolchain#18

目前这些活跃分支都已经切到 2025.10-gcc14的工具链

• dev_nuclei_5.10_v3: 支持 evalsoc v2版本, 支持RV64 & RV32，用于评估 5.10 LTS内核版本
• dev_nuclei_6.1_v3: 支持 evalsoc v2版本, 支持RV64 & RV32，用于评估 6.1 LTS内核版本
• dev_nuclei_6.6_v3: 默认分支, 支持 evalsoc v2版本, 支持RV64 & RV32，用于评估 6.6 LTS内核版本
• dev_nuclei_6.9_v3: 支持 evalsoc v2版本, 支持RV64 & RV32，用于评估 6.9内核版本（这是非LTS版本）
• dev_nuclei_6.12_v3: 支持 evalsoc v2版本, 支持RV64 & RV32，用于评估 6.12 LTS内核版本

---

下面这些分支是一些特殊功能的分支，相对功能会复杂一些，请注意使用。
下面绝大部分都只在 CORE=ux900fd BOOT_MODE=sd的场景下进行了验证，请注意！

• dev_nuclei_6.6_v3_rt: 支持evalsoc v2版本，支持RV64 & RV32，用于评估 6.6 LTS内核 + PREEMPT_RT Patch 的内核版本
• dev_nuclei_6.6_v3_spl_fit: 支持evalsoc v2版本，支持RV64 & RV32，用于评估 6.6 LTS内核，SPL -> OpenSBI -> Uboot -> Kernel 启动方式， uboot 采用FIT格式镜像启动
• dev_nuclei_6.6_v3_customsoc: 不支持Nuclei Qemu，支持Nuclei内部做的一个参考子系统，用于开发子系统中各种IP驱动(Uboot/Kernel)支持，支持的驱动参见dts，采用 freeloader 加载并引导 uboot-spl，然后uboot-spl加载its格式 opensbi + uboot的镜像并引导，然后uboot引导 kernel+rootfs its格式镜像, 只验证了rv64imafdc + SD启动模式，不建议以这个为开始，建议使用 dev_nuclei_6.6_v3 作为起始点移植，然后熟悉环境后，迁移到这个分支
• dev_nuclei_6.6_v3_optee: 支持evalsoc v2版本，但是需要硬件支持TEE + Worldguard(可选), 本分支用于验证OpTEE在6.6内核上的功能，详细参见 https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/dev_nuclei_6.6_v3_optee/optee#readme
• dev_nuclei_6.6_v3_hsm: 不支持Nuclei Qemu，支持Nuclei内部做的一个HSM + Linux参考子系统，用于验证 HSM + OpTEE安全启动流程，只验证了rv64imafdc + SD启动模式，详细流程参见 https://github.com/Nuclei-Software/nuclei-linux-sdk/blob/dev_nuclei_6.6_v3_hsm/conf/evalsoc/Nuclei_HSM_Secure_Boot.md
• dev_nuclei_6.6_v3_hypervisor: 只验证了rv64imafdc + SD启动模式，用于支持虚拟化测试，详细说明参见 https://github.com/Nuclei-Software/nuclei-linux-sdk/blob/dev_nuclei_6.6_v3_hypervisor/conf/evalsoc/linux_kvm_hypervisor_user_guide.md

---

Caution

• 下面这些分支将不会积极维护，且被弃用，且可能有问题，请注意。
• 如果确实需要使用某些特殊分支，一般情况下v3打头的分支均会有替代可用的或者类似功能的，请使用上注意。
• 下面这些分支已经不再维护，请注意使用上可能存在问题，请参考我们Linux SDK v3分支 commit历史记录做相应的更新，或者切到我们 v3分支上

• dev_nuclei_next: 支持SD卡启动和Flash启动, 请切换到 dev_nuclei_5.10_v2 分支。
  • 支持demosoc 和 evalsoc v1，基于Kernel 5.10, 支持RV64
  • 从flash启动，并借助sd卡启动linux，freeloader整合了opensbi+uboot，sd卡加载kernel+rootfs+dtb
  • 从flash直接启动，不需要依赖sd卡，freeloader整合了opensbi+uboot+kernel+rootfs+dtb（对spiflash大小有要求>=8M），也可以在uboot阶段打断启动后从SD卡启动（运行 run distro_bootcmd）
• feature/fsl: 用于评估FSL91030M 开发板，使用参见 https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/feature/fsl/conf/fsl91030m
• dev_nuclei_keystone: 主要用于评估Keystone TEE相关的方案，基于 Kernel 5.10, 支持RV64
• dev_nuclei_penglai: 主要用于评估Penglai TEE相关的方案，基于 Kernel 5.10, 支持RV64
• dev_nuclei_5.10 & dev_nuclei_6.1: 分别用于评估最新的5.10 或者 6.1 LTS版本内核，支持 evalsoc v1版本, 支持RV64
• dev_nuclei_5.10_v2 & dev_nuclei_6.1_v2: 分别用于评估最新的5.10 或者 6.1 LTS版本内核，支持 evalsoc v2版本, 支持RV64 & RV32
• dev_nuclei_6.6_v2: 用于评估6.6版本的内核，目前dts里面默认带上了 _zicbom_svpbmt 扩展(请注意)， 采用我们最新的预编译的gcc13 glibc 2.38的工具链(开发中)，支持evalsoc v2, 支持rv32 & rv64, 支持 Svnapot/Svpbmt/Zbb/Zicbom/Zicboz/Vector 特性，demosoc支持已经被删除了
• dev_nuclei_6.9_v2: 用于评估6.9版本的内核，采用我们最新的预编译的gcc13 glibc 2.38的工具链(开发中)，支持evalsoc v2, 支持rv32 & rv64, 支持 Svnapot/Svpbmt/Zbb/Zicbom/Zicboz/Vector 特性，demosoc支持已经被删除了
• dev_nuclei_6.6_v2_customsoc: 基于6.6内核增加对Nuclei SoC IP Driver的支持和测试（持续增加中），测试使用本地参考平台，支持位于 conf/customsoc, 修改的内核位于 dev_nuclei_6.6.y分支
• dev_nuclei_6.6_v2_android: 基于Android Linux Kernel 6.6版本针对 CORE=ux900fd 进行的移植和适配，用于测试AOSP的Bringup，详细使用参见该分支下的 conf/evalsoc/README.md
• feature/optee_5.10: 主要用于评估OpTEE 相关的方案，基于Kernel 5.10, , 支持RV64, 参见 Introduce OpTEE complete solution for RISC-V and looking for how to contribute it OP-TEE/optee_os#6173 和 Quick steps to evaluate optee solution on nuclei qemu #13
• feature/optee_5.10_wg: 主要用于评估OpTEE 相关的方案，基于Kernel 5.10, , 支持RV64, 同时需要CPU硬件支持更多安全特性
• dev_nuclei_6.4_v2_rt: 基于Linux 6.4内核 + RT Patches用于评估实时内核
• feature/5.10_ccm: 基于 5.10内核，增加了Linux CCM的cache 管理的适配， 代码适配，可以boot，但是需要带DMA的设备来测试这个
• dev_nuclei_5.10_v2_64baddr: 基于 5.10内核，用于测试ddr基地址大于 32位，uboot加载镜像采用FIT格式来解决之前方式只能加载32位地址空间内的镜像问题，这个分支只适配了 ux900fd - sd 模式
• dev_nuclei_5.10_v2_fit: 基于 5.10内核，用于测试ddr基地址大于 32位，uboot加载镜像采用FIT格式来解决之前方式只能加载32位地址空间内的镜像问题
• dev_nuclei_6.1_v2_fit: 基于 6.1内核，用于测试ddr基地址大于 32位，uboot加载镜像采用FIT格式来解决之前方式只能加载32位地址空间内的镜像问题
• dev_nuclei_6.6_v2_fit: 基于 6.6内核，用于测试ddr基地址大于 32位，uboot加载镜像采用FIT格式来解决之前方式只能加载32位地址空间内的镜像问题
• dev_nuclei_6.1_nommu: 基于6.1内核，用于验证no-mmu linux(aka uclinux)的支持，参见 关于各分支功能介绍 About each branch feature #2 (comment)

[fanghuaqi]

Caution

• Please pay attention to the latest issue comments, the text descriptions here may not be the latest version, refer to the specific code for accuracy.
• Branch Introduction (Chinese version) will be updated in a timely manner. The English version may no longer be updated. Please read the Chinese version (using translation) 关于各分支功能介绍 About each branch feature #2 (comment)

Introduction

As of May 2026, the updated code features are as follows:

• On 2026.05.14, the default toolchain on the v3 branch was updated from version 2025.02 to 2025.10 to fix critical bugs in the GCC toolchain. See details for reference. 关于各分支功能介绍 About each branch feature #2 (comment)
• 2025.09.10: 关于各分支功能介绍 About each branch feature #2 (comment)
• 2025.05.19: 关于各分支功能介绍 About each branch feature #2 (comment)
• 2024.12.06: 关于各分支功能介绍 About each branch feature #2 (comment)

Mainly supports the following SoCs:

• demosoc: An earlier evaluation SoC without CPU IREGION features, now deprecated and removed.

• evalsoc: The latest evaluation SoC with CPU IREGION features, evolved in two versions, with DDR base at 0xA0000000 (v1) and 0x80000000 (v2) respectively, v1 support removed.

Branches introduction:

Please note: When switching branches or switching boot modes (sd/flash), you need to clean the work directory, delete or rename it. Also when switching branches, you need to update the submodule code at the same time.
Please note: If you plan to bringup a Linux environment on your own SOC, please read our prepared bringup advice #21 first

Currently, actively development branches are dev_nuclei_5.10/6.1/6.6/6.12_v3

Note

The following branches are actively maintained branches

• Do not use the 2025.02 toolchain, as it contains known critical bugs, see Nuclei RISC-V Toolchain Known Issues riscv-mcu/riscv-gnu-toolchain#18

Currently, these active branches have all switched to the 2025.10 - gcc14 toolchain.

• dev_nuclei_5.10_v3: Supports the evalsoc v2 version, supports RV64 & RV32, and is used to evaluate the 5.10 LTS kernel version.
• dev_nuclei_6.1_v3: Supports the evalsoc v2 version, supports RV64 & RV32, and is used to evaluate the 6.1 LTS kernel version.
• dev_nuclei_6.6_v3: Default branch, supports the evalsoc v2 version, supports RV64 & RV32, and is used to evaluate the 6.6 LTS kernel version.
• dev_nuclei_6.9_v3: Supports the evalsoc v2 version, supports RV64 & RV32, and is used to evaluate the 6.9 kernel version (this is a non - LTS version).
• dev_nuclei_6.12_v3: Supports the evalsoc v2 version, supports RV64 & RV32, and is used to evaluate the 6.12 LTS kernel version.

---

The following branches are for special functions and their functions are relatively more complex. Please pay attention when using them.
Most of the following branches have only been verified in the scenario of CORE=ux900fd BOOT_MODE=sd. Please take care！

• dev_nuclei_6.6_v3_rt: Supports evalsoc v2 version, RV64 & RV32, and is used to evaluate the kernel version of 6.6 LTS kernel + PREEMPT_RT Patch.
• dev_nuclei_6.6_v3_spl_fit: Supports EvalSoC v2, RV64 & RV32. It is used to evaluate the 6.6 LTS kernel with the boot sequence SPL -> OpenSBI -> U-Boot -> Kernel. U-Boot boots using FIT format images.
• dev_nuclei_6.6_v3_customsoc: Supports a reference subsystem developed internally by Nuclei. It is used to develop the support for various IP drivers (Uboot/Kernel) in the subsystem. For the supported drivers, please refer to dts. It uses freeloader to load and boot uboot-spl, then uboot-spl loads and boots the opensbi + uboot image in its format, and then uboot boots the kernel+rootfs image in its format. Only the rv64imafdc + SD boot mode has been verified. It is not recommended to start with this. It is recommended to use dev_nuclei_6.6_v3 as the starting point for transplantation. After getting familiar with the environment, migrate to this branch.
• dev_nuclei_6.6_v3_optee: Supports the evalsoc v2 version, but requires hardware support for TEE + Worldguard (optional). This branch is used to verify the functionality of OpTEE on the 6.6 kernel, refer to https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/dev_nuclei_6.6_v3_optee/optee#readme
• dev_nuclei_6.6_v3_hsm: Supports an HSM + Linux reference subsystem developed internally by Nuclei, and is used to verify the HSM + OpTEE secure boot process. For the detailed process, please refer to https://github.com/Nuclei-Software/nuclei-linux-sdk/blob/dev_nuclei_6.6_v3_hsm/conf/evalsoc/Nuclei_HSM_Secure_Boot.md

---

Caution

The following branches will not be actively maintained.

• dev_nuclei_next: supports SD card boot and Flash boot

  • Supports demosoc and evalsoc v1, based on Kernel 5.10(RV64 only)

  • Boots from flash, and borrows SD card to boot Linux, freeloader integrates opensbi+uboot, SD card loads kernel+rootfs+dtb

  • Boots directly from flash, no dependency on SD card, freeloader integrates opensbi+uboot+kernel+rootfs+dtb (requires flash >=8M), or can boot from SD card in uboot (run run distro_bootcmd)

• feature/fsl: For evaluation of FSL91030M board, see usage at https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/feature/fsl/conf/fsl91030m

• dev_nuclei_keystone: Mainly for evaluation of Keystone TEE related solutions, based on Kernel 5.10(RV64 only)

• dev_nuclei_penglai: Mainly for evaluation of Penglai TEE related solutions, based on Kernel 5.10(RV64 only)

• dev_nuclei_5.10 & dev_nuclei_6.1: For evaluation of latest 5.10 or 6.1 LTS kernel versions, supports evalsoc v1(RV64 only)

• dev_nuclei_5.10_v2 & dev_nuclei_6.1_v2: For evaluation of latest 5.10 or 6.1 LTS kernel versions, supports evalsoc v2(RV32&RV64)

• dev_nuclei_6.6_v2: For evaluation of linux kernel 6.6，which use our latest gcc13 glibc 2.38 toolchain(WIP)，support evalsoc v2, support rv32 & rv64, support Svnapot/Svpbmt/Zbb/Zicbom/Zicboz/Vector extension，demosoc removed and dropped

• dev_nuclei_6.9_v2: For evaluation of linux kernel 6.9，which use our latest gcc13 glibc 2.38 toolchain(WIP)，support evalsoc v2, support rv32 & rv64, support Svnapot/Svpbmt/Zbb/Zicbom/Zicboz/Vector extension，demosoc removed and dropped

• dev_nuclei_6.6_v2_customsoc: Built upon the 6.6 kernel, this version includes support for Nuclei SoC IP Driver, with ongoing additions and testing. Local reference platforms are used for testing, and it supports configurations located in conf/customsoc. The modified kernel is located in the dev_nuclei_6.6.y branch.

• dev_nuclei_6.6_v2_android: Based on the Android Linux Kernel version 6.6, the porting and adaptation for CORE=ux900fd has been conducted to test the Bringup of AOSP. For detailed usage, please refer to the README.md in the conf/evalsoc branch.

• feature/optee_5.10: Mainly for evaluation of OpTEE solutions, based on Kernel 5.10(RV64 only), see Introduce OpTEE complete solution for RISC-V and looking for how to contribute it OP-TEE/optee_os#6173 and Quick steps to evaluate optee solution on nuclei qemu #13

• feature/optee_5.10_wg: Mainly for evaluation of OpTEE solutions, based on Kernel 5.10(RV64 only), requires more CPU security features

• dev_nuclei_6.4_v2_rt: Based on Linux 6.4 Kernel + RT Patches used to evaluate Realtime feature

• feature/5.10_ccm: Based on the 5.10 kernel, added the adaptation of Linux CCM cache management, code adaptation, can boot, but need a device with DMA to test this

• dev_nuclei_5.10_v2_64baddr: Based on the 5.10 kernel, used to test the ddr base address greater than 32 bits, uboot loads the image using FIT formatto solve the problem that the previous method can only load images in the 32-bit address space, this branch only adapts the ux900fd - sd mode

• dev_nuclei_5 10_v2_fit: Based on the 5.10 kernel, used to test the ddr base address is greater than 32 bits, uboot loads the image using FIT format to solve the problem that the previous method can only load the image in the 32-bit address space

• dev_nuclei_6 1_v2_fit: Based on the 6.1 kernel, used to test the ddr base address is greater than 32 bits, uboot loads the image using FIT format to solve the problem that the previous method can only load the image in the 32-bit address space

• dev_nuclei_6 6_v2_fit: Based on the 6.6 kernel, used to test the ddr base address is greater than 32 bits, uboot loads the image using FIT format to solve the problem that the previous method can only load the image in the 32-bit address space

• dev_nuclei_6.1_nommu: Based on the 6.1 kernel, it is used to verify the support for no-mmu linux (aka uclinux), see 关于各分支功能介绍 About each branch feature #2 (comment)

[fanghuaqi]

The documentation can be found in each branch's README.md, which can be reviewed online.

[fanghuaqi]

We have introduced OpTEE support, please check this issue OP-TEE/optee_os#6173

The related branches:

• feature/optee_5.10 : https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/feature/optee_5.10

• feature/optee_5.10_wg : https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/feature/optee_5.10_wg

feature/optee_5.10_wg branch introduce the support with world-guard and secure mode feature of Nuclei CPU. Currently only run on hardware, no qemu emulation support.

[fanghuaqi]

Since 2023.07, the ddr base address of our fpga emulation platform for 900 series changed from 0xA0000000 to 0x80000000, so we are able to have totally 2GB DDR RAM to use, instead of 1.5G.

If you want to try that features, please use these branches:

• dev_nuclei_5.10_v2 : https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/dev_nuclei_5.10_v2

• dev_nuclei_6.1_v2 : https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/dev_nuclei_6.1_v2

• These two branches required a new version of Nuclei QEMU > 2022.12, please contact with our AE to get it.
• These two branches are for Linux Kernel 5.10 LTS version and 6.1 LTS version.

There are also branches without _v2 naming in it, it is used for old DDR base is 0xA0000000

[fanghuaqi]

We have just introduced with no-mmu linux(aka uclinux) support for riscv64 processors.

You can evaluate it using Nuclei Qemu 2023.10 downloaded from https://www.nucleisys.com/upload/files/toochain/qemu/nuclei-qemu-2023.10-linux-x64.tar.gz

Just extract it, and add its binary path to existing system PATH.

You can find this feature in branch: https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/dev_nuclei_6.1_nommu

The freeloader will consist with loader, dts and kernel binary, when you clone this repo, and switch to this branch, and update the submodule, then you can evaluate this on qemu or hardware.

export PATH=/path/to/qemu/bin:$PATH
# choose rv64imafdc
# clean previous build if existed
make CORE=ux900fd clean
# build freeloader is enough, no need to build boot images, sd card is not needed
# bitstream with 50MHz CPU is expected by default
make CORE=ux900fd freeloader
# run on qemu
make CORE=ux900fd run_qemu
# upload to hardware board, hardware need to be power on and jtag connected
# boot need a few minutes depended on cpu frequency
make CORE=ux900fd upload_freeloader

Sample output on qemu is attached here:
rv64imafdc_nommu_linux_bootlog.txt

[matthewgui]

We have just introduced with preempt_rt linux support for riscv64 processors.

You can evaluate it using Nuclei Qemu 2023.10 downloaded from https://www.nucleisys.com/upload/files/toochain/qemu/nuclei-qemu-2023.10-linux-x64.tar.gz

Just extract it, and add its binary path to existing system PATH.

You can find this feature in branch: https://github.com/Nuclei-Software/nuclei-linux-sdk/tree/dev_nuclei_6.4_v2_rt

The freeloader will consist with loader, dts and kernel binary, when you clone this repo, and switch to this branch, and update the submodule, then you can evaluate this on qemu or hardware.

export PATH=/path/to/qemu/bin:$PATH
# choose rv64imafdc
# clean previous build if existed
make CORE=ux900fd clean
# build freeloader is enough, no need to build boot images, sd card is not needed
# bitstream with 50MHz CPU is expected by default
make CORE=ux900fd freeloader
# run on qemu
make CORE=ux900fd run_qemu
# upload to hardware board, hardware need to be power on and jtag connected
# boot need a few minutes depended on cpu frequency
make CORE=ux900fd upload_freeloader

Sample output on qemu is attached here:
rv64imafdc_rt_linux_bootlog.txt

cyclictest program which we use to test rtlinux, is built from rt-test source code,

rt-test git source : git://git.kernel.org/pub/scm/utils/rt-tests/rt-tests.git

here is our rv64fd binary built from rt-test 2.0 ,numa library is master branch
cyclictest.gz

[fanghuaqi]

We just introduced support of Linux Kernel 6.6 in branch dev_nuclei_6.6_v2, which is using prebuilt gcc 13 + glibc 2.38 toolchain, the buildroot/uboot are also upgraded to latest stable branch.

The riscv features linux kernel 6.6 supported:

[fanghuaqi]

We introduced dev_nuclei_6.6_v2_customsoc branch, mainly used to demonstrate our Nuclei SoC IP linux driver code and how to use it.

[fanghuaqi]

We introduced Linux perf tool support which may cause cycle/instret not able to be read in user space, see #26

[fanghuaqi]

In 2024.12.06, we have updated the following branches, ALL CI PASSED using Nuclei Qemu 2024.06:

• dev_nuclei_5.10_v2: kernel version upgraded to v5.10.230, see e6a2fc1...194cabd
• dev_nuclei_6.1_v2: kernel version upgraded to v6.1.119, see 7d6bffc...d87f8cd
• dev_nuclei_6.6_v2: kernel version upgraded to v6.6.63, and xec driver are added for evalsoc, now default require _zicbom_svpbmt extensions due to xec driver supported in f8f6d7b, see 92a146d...5bd9bbb
• dev_nuclei_6.9_v2: kernel version upgraded to v6.9.12, see d41a083...8b6ba81

All of the above freeloader updated to Nuclei-Software/freeloader@420a78e , mainly added ENABLE_LDSPEC and SPFL1DCTRL4 variable support.

[fanghuaqi]

In 2025.05.19, we have updated these branches dev_nuclei_5.10/6.1/6.6/6.9_v2, ALL CI PASSED using Nuclei Qemu 2025.02.

And we also create new branches endswith _v3 such as dev_nuclei_5.10/6.1/6.6/6.9/6.12_v3, and ALL CI PASSED using Nuclei Qemu 2025.02, and these _v3 branches are using Nuclei RISC-V Toolchain 2025.02(gcc14), and later on, we will only maintain the _v3 branches, and other functional branches will also migrate to use 2025.02(gcc14) toolchain.

[fanghuaqi]

In 2025.05.19, We updated the code under the _v3_* branches, added PMUv2 and XEC Ethernet support to the evalsoc configuration, updated freeloader and OpenSBI to adapt to new CPU features (such as TLB control and prefetching), and also fixed compilation warnings, 64-bit address errors, and optimized the CI process, for details, please check each branch commit history.

eg. for branch dev_nuclei_6.6_v3, click https://github.com/Nuclei-Software/nuclei-linux-sdk/commits/dev_nuclei_6.6_v3/

You can switch branch like this: