RFC: Riscv bare metal CI job #31425

sedited commented at 8:30 AM on December 5, 2024: contributor

This adds a CI job for building the static consensus library and linking it to an executable. It uses newlib-cygwin as a C library for the final linking step. This ensure compatibility with this target going forward and can serve as a starting point for enabling bare metal builds for the entire kernel library. This would have also caught the error fixed in #31365.

DrahtBot commented at 8:30 AM on December 5, 2024: contributor

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/31425.

Reviews

See the guideline for information on the review process.

Type	Reviewers
ACK	willcl-ark
Concept ACK	laanwj, hebasto, fanquake

If your review is incorrectly listed, please copy-paste <code></code> into the comment that the bot should ignore.

Conflicts

Reviewers, this pull request conflicts with the following ones:

#34411 (Full Libevent removal by fanquake)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

sedited force-pushed on Dec 5, 2024

DrahtBot commented at 9:12 AM on December 5, 2024: contributor

🚧 At least one of the CI tasks failed. <sub>Debug: https://github.com/bitcoin/bitcoin/runs/33960779294</sub>

<details><summary>Hints</summary>

Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.
A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.
An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

</details>

DrahtBot added the label CI failed on Dec 5, 2024

maflcko commented at 9:16 AM on December 5, 2024: member

can serve as a starting point for enabling bare metal builds for the entire kernel library.

Interesting. Do you think this is possible at all, given that the kernel library links leveldb, which I'd presume is not bare-metal ready?

So I guess this mostly serves as a check that users can ship their own-brewed libbitcoinconsensus (or so, or subset of it)?

sedited force-pushed on Dec 5, 2024

sedited commented at 9:26 AM on December 5, 2024: contributor

Interesting. Do you think this is possible at all, given that the kernel library links leveldb, which I'd presume is not bare-metal ready?

Yes, definitely not ready. I think the main hurdle is the background compaction, which I am not sure how to tackle. Maybe we'll find a solution for it eventually though, either by patching it, or allowing the user to bring their own utxos.

So I guess this mostly serves as a check that users can ship their own-brewed libbitcoinconsensus (or so, or subset of it)?

Yes, that is the goal for now.

sedited marked this as ready for review on Dec 5, 2024

sedited force-pushed on Dec 5, 2024

in ci/test/03_test_script.sh:168 in 4910ae5d0d outdated

 163 | +        -Wl,--no-whole-archive \
 164 | +        src/crypto/libbitcoin_crypto.a \
 165 | +        src/secp256k1/lib/libsecp256k1.a \
 166 | +        /opt/riscv-ilp32/riscv32-unknown-elf/lib/libstdc++.a \
 167 | +        /riscv/newlib/build/riscv32-unknown-elf/newlib/libc.a \
 168 | +        /riscv/newlib/build/riscv32-unknown-elf/newlib/libm.a \

laanwj commented at 11:20 AM on December 5, 2024:

Any specific reason to use the intermediate build and not the installed libraries from /opt/newlib, here?

in ci/test/01_base_install.sh:98 in 4910ae5d0d outdated

  93 | +
  94 | +    ${CI_RETRY_EXE} git clone --depth=1 https://sourceware.org/git/newlib-cygwin.git -b topic/3.6 /riscv/newlib
  95 | +    cd /riscv/newlib
  96 | +    mkdir build && cd build
  97 | +    ../configure \
  98 | +        --target=riscv32-unknown-elf --disable-newlib-io-float --enable-newlib-io-long-long --enable-newlib-io-long-double --with-arch=rv32gc --with-abi=ilp32 --disable-shared --disable-multilib\

laanwj commented at 11:22 AM on December 5, 2024:

Are you sure enabling i/o for long-double is needed? i don't believe we use this type anywhere.

sedited commented at 2:25 PM on December 6, 2024:

Sorry, all these flags were a mess. I was experimenting with linking in a range of other functionality, as well as running it on linux directly, and didn't prune stuff out nicely. Removed most of them again.

laanwj commented at 11:35 AM on December 5, 2024: member

It uses newlib-cygwin as a C library for the final linking step.

Mentioning this because i had to look it up to be sure: newlib-cygwin has nothing to do with Windows whatsoever. It's simply a minimalist libc.

I think the main hurdle is the background compaction, which I am not sure how to tackle.

Could be a periodic foreground task, if threads aren't available? But yes, this would imply patching leveldb, there is no such API right now.

laanwj added the label Build system on Dec 5, 2024

laanwj added the label Tests on Dec 5, 2024

DrahtBot removed the label CI failed on Dec 5, 2024

in ci/test/01_base_install.sh:89 in 4910ae5d0d outdated

  83 | @@ -84,6 +84,29 @@ if [[ ${USE_MEMORY_SANITIZER} == "true" ]]; then
  84 |    rm -rf /msan/llvm-project
  85 |  fi
  86 |  
  87 | +if [[ ${BARE_METAL_RISCV} == "true" ]]; then
  88 | +    ${CI_RETRY_EXE} git clone --depth=1 https://github.com/riscv-collab/riscv-gnu-toolchain -b 2024.11.22 /riscv/gcc
  89 | +    cd /riscv/gcc

maflcko commented at 1:35 PM on December 5, 2024:

style-wise, it would be good to not use cd in the CI scripts, because it affects the global state for all remaining lines.

It is better to wrap it into (), for example ( cd a ; foo(); ) (or similar).

in ci/test/01_base_install.sh:107 in 4910ae5d0d outdated

 102 | +        AR_FOR_TARGET=/opt/riscv-ilp32/bin/riscv32-unknown-elf-ar \
 103 | +        RANLIB_FOR_TARGET=/opt/riscv-ilp32/bin/riscv32-unknown-elf-ranlib \
 104 | +        CFLAGS_FOR_TARGET="-march=rv32gc -mabi=ilp32 -mcmodel=medlow "\
 105 | +        CXXFLAGS_FOR_TARGET="-std=c++20 -march=rv32gc -mabi=ilp32 -mcmodel=medlow"
 106 | +    make -j "$MAKEJOBS"
 107 | +    make install

maflcko commented at 1:38 PM on December 5, 2024:

It would be good to rm -rf everything duplicate. Otherwise, you are using up space twice:

$ podman image ls | grep riscv
localhost/ci_native_riscv_bare  latest      dfa9b8223b62  5 minutes ago  13.9 GB

See the llvm build on how to do this.

sedited commented at 2:39 PM on December 6, 2024:

Should be better now:

docker image ls | grep riscv
ci_native_riscv_bare   latest    55627eefe6d7   3 minutes ago   2.8GB

sedited force-pushed on Dec 6, 2024

sedited commented at 3:39 PM on December 6, 2024: contributor

Updated 4910ae5d0d9954b8b811d7c52e3539979ea46016 -> f27760012b3e236933ea5d1b39a6ba74884df1a2 (bare_metal_support_0 -> bare_metal_support_1, compare)

Addressed @maflcko's comment, removing sources after install step.
Addressed @maflcko's comment, wrapped cd step into a subshell
Addressed @laanwj's comment, use the installed lib
Addressed @laanwj's comment, removing a bunch of unneeded/superfluous flags
Added a start section to the binary for the global pointer and returning an exit code. Though not needed, since we are only checking that it links, I feel like this makes the example a bit clearer.

in ci/test/03_test_script.sh:154 in f27760012b outdated

 149 | +              la gp, __global_pointer$
 150 | +              .option pop
 151 | +
 152 | +              call main
 153 | +
 154 | +              # Put Exit2 system call number into the a7 register

laanwj commented at 12:46 PM on December 10, 2024:

concept ACK on making it actually runnable somewhat i was confused for a moment here, as to what syscall numbers mean for bare-metal maybe add "Linux" to the comment

laanwj commented at 12:58 PM on December 10, 2024: member

Concept ACK, this looks like the minimum required to sanity check that libconsensus.a can be compiled for, and linked for bare-metal RISC-V. It is not enough to test that it actually works (this would require a lot more, quite nasty low-level code), but maybe that's out of scope for this project. At the least it is for this PR.

hebasto commented at 10:53 AM on December 14, 2024: member

Concept ACK.

in CMakeLists.txt:377 in f27760012b outdated

 373 | @@ -372,8 +374,10 @@ if(BUILD_FUZZ_BINARY)
 374 |    )
 375 |  endif()
 376 |  
 377 | +if(NOT CMAKE_SYSTEM_NAME STREQUAL "Generic")

hebasto commented at 2:36 PM on February 3, 2025:

I imagine that expanding this build scenario might enable building boost and libevent in depends, no?

If so, the Boost check should have another option to be disabled.

Additionally, mind considering this comment: https://github.com/bitcoin/bitcoin/blob/1172bc4157eefe80d1aaf0b56459857ec651e535/cmake/module/AddBoostIfNeeded.cmake#L7-L8

which, in turn, was based on this legacy code:https://github.com/bitcoin/bitcoin/blob/32efe850438ef22e2de39e562af557872a402c31/configure.ac#L1247-L1251

DrahtBot added the label Needs rebase on Mar 31, 2025

sedited force-pushed on Apr 3, 2025

DrahtBot removed the label Needs rebase on Apr 3, 2025

DrahtBot added the label CI failed on Apr 3, 2025

DrahtBot commented at 6:00 AM on April 4, 2025: contributor

CI failure:

[12:50:33.743] gmake: *** No rule to make target 'install'.  Stop.

maflcko commented at 8:38 AM on May 21, 2025: member

Coming from #32460 (comment), I noticed that https://www.sourceware.org/newlib/libc.html doesn't list ftruncate, so I guess the build will fail once more code is compiled/linked?

fanquake commented at 8:41 AM on May 21, 2025: member

I think the docs might be incomplete / outdated? See https://github.com/bminor/newlib/blob/b39b510c1ce68757e79410585262ca2cd48da839/newlib/libc/include/sys/unistd.h#L287.

DrahtBot added the label Needs rebase on Jul 29, 2025

sedited force-pushed on Aug 7, 2025

sedited commented at 7:59 PM on August 7, 2025: contributor

Rebased f27760012b3e236933ea5d1b39a6ba74884df1a2 -> ec7c86c732c995d2c38e2a3f93ad55a451a8cf81 (bare_metal_support_1 -> bare_metal_support_2, compare)

Fixed a bunch of silent and proper merge conflicts.

DrahtBot removed the label Needs rebase on Aug 7, 2025

DrahtBot removed the label CI failed on Aug 7, 2025

DrahtBot added the label Needs rebase on Sep 3, 2025

sedited force-pushed on Sep 4, 2025

sedited commented at 4:08 PM on September 4, 2025: contributor

Rebased ec7c86c732c995d2c38e2a3f93ad55a451a8cf81 -> a577bbe5df766a4e0e5a36fc997b7880eec45c0e (bare_metal_support_2 -> bare_metal_support_3, compare)

Fixed conflict with #32989

DrahtBot removed the label Needs rebase on Sep 4, 2025

sedited force-pushed on Sep 17, 2025

sedited commented at 11:44 AM on September 17, 2025: contributor

Rebased a577bbe5df766a4e0e5a36fc997b7880eec45c0e -> e254de76ac0a390569bc5b561f61babb6d021dcb (bare_metal_support_3 -> bare_metal_support_4, compare)

sedited added this to a project on Dec 14, 2025

sedited changed the project status on Dec 14, 2025

DrahtBot added the label Needs rebase on Dec 22, 2025

sedited force-pushed on Dec 23, 2025

sedited commented at 11:26 AM on December 23, 2025: contributor

Rebased e254de76ac0a390569bc5b561f61babb6d021dcb -> dc53679c60c3a5758700002bbdca6a5ab112c24c (bare_metal_support_4 -> bare_metal_support_5, compare)

Fixed conflict with #33810

DrahtBot removed the label Needs rebase on Dec 23, 2025

fanquake commented at 11:03 AM on February 9, 2026: member

Concept ACK - Similar to #34421, if there are reservations about having this run in the CI, we can at least add the config.

in ci/test/03_test_script.sh:214 in dc53679c60 outdated

 209 | +        "${BASE_BUILD_DIR}"/src/secp256k1/lib/libsecp256k1.a \
 210 | +        /opt/riscv-ilp32/riscv32-unknown-elf/lib/libstdc++.a \
 211 | +        /opt/newlib/riscv32-unknown-elf/lib/libc.a \
 212 | +        /opt/newlib/riscv32-unknown-elf/lib/libm.a \
 213 | +        /opt/riscv-ilp32/lib/gcc/riscv32-unknown-elf/14.2.0/libgcc.a \
 214 | +        -o test.elf

fanquake commented at 11:31 AM on February 9, 2026:

It could be nice to call file/ldd or something similar, on the produced outputs, so it's more clear what is being built. Otherwise the end-of run output is a bit hard to parse:

+ /opt/riscv-ilp32/bin/riscv32-unknown-elf-gcc -c start.s -o start.o
+ echo -e '#include <sys/stat.h>
          void _exit(int code) { while(1); }
          int _sbrk(int incr) { return 0; }
          int _write(int file, char *ptr, int len) { return 0; }
          int _close(int file) { return -1; }
          int _fstat(int file, struct stat *st) { st->st_mode = S_IFCHR; return 0; }
          int _isatty(int file) { return 1; }
          int _lseek(int file, int ptr, int dir) { return 0; }
          int _read(int file, char *ptr, int len) { return 0; }
          int _kill(int pid, int sig) { return -1; }
          int _getpid(void) { return -1; }'
+ /opt/riscv-ilp32/bin/riscv32-unknown-elf-gcc -g -march=rv32i -mabi=ilp32 -c syscalls.c -o syscalls.o
+ /opt/riscv-ilp32/bin/riscv32-unknown-elf-g++ -g -std=c++20 -march=rv32gc -mabi=ilp32 -nostdlib /opt/riscv-ilp32/lib/gcc/riscv32-unknown-elf/14.2.0/crtbegin.o test.o start.o syscalls.o /ci_container_base/ci/scratch/build-riscv32-unknown-elf-gcc/lib/libbitcoin_consensus.a /ci_container_base/ci/scratch/build-riscv32-unknown-elf-gcc/lib/libbitcoin_crypto.a /ci_container_base/ci/scratch/build-riscv32-unknown-elf-gcc/src/secp256k1/lib/libsecp256k1.a /opt/riscv-ilp32/riscv32-unknown-elf/lib/libstdc++.a /opt/newlib/riscv32-unknown-elf/lib/libc.a /opt/newlib/riscv32-unknown-elf/lib/libm.a /opt/riscv-ilp32/lib/gcc/riscv32-unknown-elf/14.2.0/libgcc.a -o test.elf
+ '[' -n '' ']'
+ '[' '' = true ']'
+ '[' false = true ']'
+ '[' false = true ']'
+ '[' false = true ']'
+ [[ '' == true ]]
+ '[' false = true ']'
Stop and remove CI container by ID
+ docker container kill cfdbe4713beee3e4d396bd9d9226c99efafd3679bb04acdb89ec063eae8402d5
Emulate Docker CLI using podman. Create /etc/containers/nodocker to quiet msg.
cfdbe4713beee3e4d396bd9d9226c99efafd3679bb04acdb89ec063eae8402d5

sedited commented at 9:47 AM on February 10, 2026:

Added file:

+ file test.elf
test.elf: ELF 32-bit LSB executable, UCB RISC-V, RVC, soft-float ABI, version 1 (SYSV), statically linked, with debug_info, not stripped

sedited force-pushed on Feb 10, 2026

sedited commented at 9:46 AM on February 10, 2026: contributor

Updated dc53679c60c3a5758700002bbdca6a5ab112c24c -> 774042bb0eecee783ab04e0cb53f762b71984e77 (bare_metal_support_5 -> bare_metal_support_6, compare)

Took @fanquake's suggestion, added file command to print final build artifact's information.
Addressed @laanwj's comment, added a small comment indicating that making the binary executable on linux serves debugging purposes.

DrahtBot added the label Needs rebase on Apr 9, 2026

sedited force-pushed on Apr 22, 2026

sedited commented at 8:32 PM on April 22, 2026: contributor

Rebased 774042bb0eecee783ab04e0cb53f762b71984e77 -> 0de648ca1e71cdb76883dc2e31f4c7e630528d27 (bare_metal_support_6 -> bare_metal_support_7, compare)

Added some more workarounds after the recent changes to the aes code included the secure allocator, which pulls in the lockedpool, which in turn does not make sense in its current form for bare metal targets.

DrahtBot removed the label Needs rebase on Apr 23, 2026

DrahtBot added the label Needs rebase on May 26, 2026

sedited force-pushed on May 26, 2026

sedited commented at 12:25 PM on May 26, 2026: contributor

Updated 0de648ca1e71cdb76883dc2e31f4c7e630528d27 -> 50fc04c18cb226bf7545698bcabd1f0028f253cd (bare_metal_support_7 -> bare_metal_support_8, compare)

Fixed conflict with #33974

DrahtBot added the label CI failed on May 26, 2026

DrahtBot removed the label Needs rebase on May 26, 2026

DrahtBot removed the label CI failed on May 28, 2026

in .github/workflows/ci.yml:541 in 50fc04c18c

 536 | @@ -537,6 +537,12 @@ jobs:
 537 |              timeout-minutes: 120
 538 |              file-env: './ci/test/00_setup_env_native_msan.sh'
 539 |  
 540 | +          - name: 'riscv32 bare metal, static libbitcoin_consensus'
 541 | +            cirrus-runner: 'ghcr.io/cirruslabs/ubuntu-runner-amd64:24.04-lg'

fanquake commented at 10:00 AM on June 17, 2026:

Can switch this to:

            warp-runner: 'warp-ubuntu-latest-x64-16x'
            fallback-runner: 'ubuntu-latest'

in ci/test/00_setup_env_riscv_bare_cross.sh:3 in 50fc04c18c

   0 | @@ -0,0 +1,37 @@
   1 | +#!/usr/bin/env bash
   2 | +#
   3 | +# Copyright (c) 2019-present The Bitcoin Core developers

fanquake commented at 10:00 AM on June 17, 2026:

# Copyright (c) The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or https://opensource.org/license/mit.

in ci/test/00_setup_env_riscv_bare_cross.sh:12 in 50fc04c18c

   7 | +export LC_ALL=C.UTF-8
   8 | +
   9 | +export CONTAINER_NAME=ci_native_riscv_bare
  10 | +
  11 | +export GOAL="bitcoin_consensus bitcoin_crypto secp256k1"
  12 | +export CI_IMAGE_NAME_TAG="docker.io/ubuntu:24.04"

fanquake commented at 10:01 AM on June 17, 2026:

export CI_IMAGE_NAME_TAG="mirror.gcr.io/ubuntu:26.04"

in ci/test/01_base_install.sh:88 in 50fc04c18c

  83 | @@ -84,6 +84,29 @@ if [[ -n "${USE_INSTRUMENTED_LIBCPP}" ]]; then
  84 |    rm -rf /llvm-project
  85 |  fi
  86 |  
  87 | +if [[ ${BARE_METAL_RISCV} == "true" ]]; then
  88 | +    ${CI_RETRY_EXE} git clone --depth=1 https://github.com/riscv-collab/riscv-gnu-toolchain -b 2024.11.22 /riscv/gcc

fanquake commented at 10:08 AM on June 17, 2026:

2024.11.22

Should this point to any particular release (can't tell from upstream tags, which are all nightly, what should be used)?

sedited commented at 4:37 PM on June 17, 2026:

This basically just needs a compatible host. Looks like you need to look at the submodule information to actually find out what is being versioned? I don't think it matters too much as long as everything links fine.

in ci/test/03_test_script.sh:170 in 50fc04c18c outdated

 166 | @@ -167,6 +167,62 @@ if [ -n "${CI_LIMIT_STACK_SIZE}" ]; then
 167 |    ulimit -s 512
 168 |  fi
 169 |  
 170 | +if [[ ${BARE_METAL_RISCV} == "true" ]]; then

fanquake commented at 10:10 AM on June 17, 2026:

This chunk is a lot to have inlined here. Could split it into it's own script?

sedited commented at 3:39 PM on June 17, 2026:

Could do that, but not sure where to put.

maflcko commented at 6:12 AM on June 18, 2026:

You could put it in "${BASE_ROOT_DIR}/ci/test/ like some other ci test snippets.

fanquake commented at 10:12 AM on June 17, 2026: member

I think this is something we should be testing, and would like to see it move forward.

in ci/test/03_test_script.sh:221 in 50fc04c18c

 216 | +        "${BASE_BUILD_DIR}"/src/secp256k1/lib/libsecp256k1.a \
 217 | +        /opt/riscv-ilp32/riscv32-unknown-elf/lib/libstdc++.a \
 218 | +        /opt/newlib/riscv32-unknown-elf/lib/libc.a \
 219 | +        /opt/newlib/riscv32-unknown-elf/lib/libm.a \
 220 | +        /opt/riscv-ilp32/lib/gcc/riscv32-unknown-elf/14.2.0/libgcc.a \
 221 | +        -o test.elf

willcl-ark commented at 3:56 PM on June 17, 2026:

As an interim, how about force-linking the whole archive, while test only has ScriptErrorString. Otherwise the linker can ignore everything else no?

    /opt/riscv-ilp32/bin/riscv32-unknown-elf-g++ -g -std=c++20 -march=rv32gc -mabi=ilp32 \
        -nostdlib \
        /opt/riscv-ilp32/lib/gcc/riscv32-unknown-elf/14.2.0/crtbegin.o \
        test.o \
        start.o \
        syscalls.o \
         -Wl,--whole-archive \
        "${BASE_BUILD_DIR}"/lib/libbitcoin_consensus.a \
        "${BASE_BUILD_DIR}"/lib/libbitcoin_crypto.a \
        "${BASE_BUILD_DIR}"/src/secp256k1/lib/libsecp256k1.a \
         -Wl,--no-whole-archive \
        /opt/riscv-ilp32/riscv32-unknown-elf/lib/libstdc++.a \
        /opt/newlib/riscv32-unknown-elf/lib/libc.a \
        /opt/newlib/riscv32-unknown-elf/lib/libm.a \
        /opt/riscv-ilp32/lib/gcc/riscv32-unknown-elf/14.2.0/libgcc.a \
        -o test.elf

sedited force-pushed on Jun 17, 2026

sedited commented at 4:35 PM on June 17, 2026: contributor

Rebased and updated 50fc04c18cb226bf7545698bcabd1f0028f253cd -> 0558992d33f336790721920dd57d17441a6c9cea (bare_metal_support_8 -> bare_metal_support_9, compare)

Updated to newest riscv toolchain tag and modernized the script a bit, allowing to remove the external newlib and use the version shipped with the toolchain repository.
Addressed @willcl-ark's comment, added whole-archive flags.
Addressed @fanquake's comment, switched to warp runners.
Addressed @fanquake's comment, corrected copyright notice.
Addressed @fanquake's comment, migrated to ubuntu 26.04

in ci/test/03_test_script.sh:171 in bff8027243

 166 | @@ -167,6 +167,72 @@ if [ -n "${CI_LIMIT_STACK_SIZE}" ]; then
 167 |    ulimit -s 512
 168 |  fi
 169 |  
 170 | +if [[ ${BARE_METAL_RISCV} == "true" ]]; then
 171 | +    echo -e "#include <script/script_error.h>\n int main() { return ScriptErrorString(ScriptError_t::SCRIPT_ERR_UNKNOWN_ERROR).size() > 0; }" > test.cpp

willcl-ark commented at 9:38 AM on June 18, 2026:

In bff80272432f8393651ce53cd0be9a5123490b41

Yeah, I agree with fanquake/marco that this assembly/syscall stub/linking section is not really test orchestration, so keeping it inline in 03_test_script.sh makes that shared script harder to read.

As suggested previously, could we move the generated test.cpp, start.s, syscalls.c, and final link command into a dedicated helper, e.g. ${BASE_ROOT_DIR}/ci/test/link_riscv_bare_consensus.sh, and have 03_test_script.sh just call that helper when BARE_METAL_RISCV=true?

willcl-ark commented at 9:45 AM on June 18, 2026:

I see this was actioned before I could hit send! :)

sedited force-pushed on Jun 18, 2026

sedited commented at 9:40 AM on June 18, 2026: contributor

Updated 0558992d33f336790721920dd57d17441a6c9cea -> fcbf52fdd1b91298ab81a7dde3063554826f32a0 (bare_metal_support_9 -> bare_metal_support_10, compare)

Addressed @fanquake's comment, split linking steps into their own script.
Disable gdb for the toolchain, which slims down the build a bit.

willcl-ark commented at 9:44 AM on June 18, 2026: member

Approach ACK

this CI job gives an early warning if libbitcoin_consensus.a, libbitcoin_crypto.a, or libsecp256k1.a start depending on hosted OS assumptions that break a riscv32-unknown-elf bare-metal-style link. although using generic I think will actually help catch a class of errors which may apply to other bare metal targets too.

it seems therefore like a useful minimal guard for keeping the consensus-related static archive linkable in a freestanding environment, and @sedited already highlighted one bug which would have been caught if we'd had this job.

however it is currently only a compile/link smoke test. it doesn't run the ELF, boot on hardware, exercise script verification, or prove broader bare-metal support. (not goals of this PR, either). the handwritten _start, syscall stubs, and link recipe are also currently embedded in the generic CI script.

follow ups which I can think of as being interesting might be to link a small real bitcoinconsensus_verify_script caller, and run the ELF under QEMU.

in .github/workflows/ci.yml:527 in fcbf52fdd1 outdated

 522 | @@ -523,6 +523,12 @@ jobs:
 523 |              timeout-minutes: 120
 524 |              file-env: './ci/test/00_setup_env_native_msan.sh'
 525 |  
 526 | +          - name: 'riscv32 bare metal, static libbitcoin_consensus'
 527 | +            warp-runner: 'warp-ubuntu-latest-x64-16x'

willcl-ark commented at 2:35 PM on June 22, 2026:

I think it would be good to see if we can downgrade this to 8x after it's been merged here. It's only 10 minutes long, and will likely get even shorter when hitting more caches.

Generally, it's better (cheaper) for us to use a slower CI instance, if we can tolerate the longer runtimes. As this one appears to be pretty quick (~ 10 minutes) it could make sense to downgrade to 8x in the future IMO.

willcl-ark approved

willcl-ark commented at 2:35 PM on June 22, 2026: member

ACK fcbf52fdd1b91298ab81a7dde3063554826f32a0

Thjis LGTM now. I'm sure we will find more improvements to make to it, but it already serves a useful purpose, and looks to be implemented correctly according to it's current intended purpose.

DrahtBot requested review from hebasto on Jun 22, 2026

DrahtBot requested review from laanwj on Jun 22, 2026

DrahtBot requested review from fanquake on Jun 22, 2026

DrahtBot added the label Needs rebase on Jun 23, 2026

build: Add option for building for bare metal envs

A bare metal build is now supported by setting CMAKE_SYSTEM_NAME=Generic

Skip the platform-dependent feature checks, such as threads and atomics,
which are typically not available on bare metal. Also only make the
boost headers mandatory if they exist for the target.

Also exclude aes from the crypto library, since that requires the secure
allocator, which uses more advance features, such as mutexes.

a9a1d92a1d

Add CI job for producing a static bare metal binary bfdbf513f6

Add CI job for riscv bare metal b36730a3ef

sedited force-pushed on Jun 25, 2026

sedited commented at 8:28 AM on June 25, 2026: contributor

Rebased fcbf52fdd1b91298ab81a7dde3063554826f32a0 -> b36730a3efc85c4acdb93f06910e37151b8f2cf9 (bare_metal_support_10 -> bare_metal_support_11, compare)

Fixed conflict with #34411

willcl-ark approved

willcl-ark commented at 8:44 AM on June 25, 2026: member

reACK b36730a3efc85c4acdb93f06910e37151b8f2cf9

Checked range-diff only

$ git range-diff fcbf52fdd1b...b36730a3efc

 -:  ----------- > 87:  703a671fbc2 fuzz: compact coins view db during fuzzing
 1:  29af6df7e91 ! 88:  a9a1d92a1da build: Add option for building for bare metal envs
    @@ CMakeLists.txt: endif()
      add_boost_if_needed()
     +endif()

    - if(BUILD_DAEMON OR BUILD_GUI OR BUILD_CLI OR BUILD_TESTS OR BUILD_BENCH OR BUILD_FUZZ_BINARY)
    -   find_package(Libevent 2.1.8 MODULE REQUIRED)
    + if(ENABLE_WALLET)
    +   if(VCPKG_TARGET_TRIPLET)

      ## cmake/introspection.cmake ##
     @@ cmake/introspection.cmake: if(NOT WIN32)
    @@ src/CMakeLists.txt: target_link_libraries(bitcoin_node
          univalue
     -    Boost::headers
     +    $<TARGET_NAME_IF_EXISTS:Boost::headers>
    -     $<TARGET_NAME_IF_EXISTS:libevent::core>
    -     $<TARGET_NAME_IF_EXISTS:libevent::extra>
    -     $<TARGET_NAME_IF_EXISTS:libevent::pthreads>
    +     $<TARGET_NAME_IF_EXISTS:USDT::headers>
    + )
    + if(WITH_EMBEDDED_ASMAP)

      ## src/crypto/CMakeLists.txt ##
     @@
 2:  bfcbc99953e = 89:  bfdbf513f69 Add CI job for producing a static bare metal binary
 3:  fcbf52fdd1b = 90:  b36730a3efc  Add CI job for riscv bare metal

DrahtBot removed the label Needs rebase on Jun 25, 2026

fanquake commented at 11:51 AM on June 25, 2026: member

Guix Build:

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