[lgirdwood]

Phase 2 of #11306 (kernel / user-space partition), second part: move the inter-core communication code to src/kernel/idc. Follows #11394.

Patches

• src/idc → src/kernel/idc: a pure move. The code is now built into the sof_kernel library added in Phase 2 (part 1): add src/kernel and a sof_kernel library, move src/init #11394.
  • Kconfig: a new src/kernel/Kconfig sources the Kconfig files of the moved directories. src/Kconfig sources it in place of idc/Kconfig, and the option values are unchanged.
  • README: the relative link is fixed.
  • Host builds: only Zephyr builds the IDC code, so they are not affected.
• Docs: AGENTS.md, the user-space README and the audio README list the kernel-only directories by name. They now list src/kernel, note the sof_kernel library, and keep the directories that have not moved yet. This also covers src/init, which Phase 2 (part 1): add src/kernel and a sof_kernel library, move src/init #11394 moved but did not update here.

Functional change

None. The objects are unchanged, and every build's .config has the same option values before and after. As in #11394, the only effect is on link order: in every firmware image the symbols (name, type and size) and the SYS_INIT() order are identical, and only alignment padding in some sections changes. Two more link-order effects:

• PTL builds with Zephyr userspace: the generated kernel-object hash table (kobject_hash.c, wordlist) changes size. gperf generates it from the kernel objects' addresses, which move with the link order.
• Cortex-M7 builds: sof_init() changes size with the commit hash it embeds, as explained in Phase 2 (part 1): add src/kernel and a sof_kernel library, move src/init #11394.

Testing

• Per commit:
  • Builds: every commit was built on tgl, tgl-h, mtl, lnl, ptl, wcl, nvl, imx8, imx8x, imx8m, imx8m_cm7, imx8ulp, imx95 and qemu_xtensa, and in the extra CI configurations:
    • native_sim IPC3/IPC4 stub builds;
    • imx93 64-bit;
    • PTL with each userspace overlay;
    • PTL with CONFIG_SOF_USERSPACE_PROXY=n;
    • PTL and MTL with os_linux_overlay.conf;llext_relocatable.conf.
  • Objects and LLEXT modules: same non-debug section sizes as the previous commit.
  • Firmware images: compared for symbols, SYS_INIT() order and section sizes.
  • Cadence xt-clang (RI-2022.10): MTL, PTL and NVL compile.
  • Host: the host library and cmocka build and pass.
• At the tip:
  • all cmocka configurations, the testbench and the tools pass;
  • the platforms that already fail on main (acp_6_0, acp_7_0, acp_7_x, mt8186, mt8188, mt8195, mt8196, mt8365) have unchanged error sets.
• Hardware: TGL (UP Xtreme i11) with sof-hda-generic-cavs25-2ch.tplg boots, plays 5 s on the HDA analog PCM, and plays again after runtime suspend, with no DSP errors.

All of the above was run on 78b23ad with #11394 applied. After the rebase onto d3f51d0 (current main, including #11394), the patches are unchanged, and the firmware builds, the host library and cmocka were repeated at the tip.

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

No active review issues block the kernel/userspace reorganization.

No open issues 🎉

What changed in this PR

Continues the kernel/userspace partition in #11306 by moving inter-core communication into src/kernel/idc. The stacked changes from #11394 also establish sof_kernel and relocate initialization code, with no intended functional changes.

Changes:

• Build IDC and initialization code under the dedicated sof_kernel library.
• Route IDC configuration through src/kernel/Kconfig, preserving option values.
• Update documentation paths, kernel-tier guidance, and a test-support comment.

File	Description
zephyr/​CMakeLists.txt	Creates and links sof_kernel, adds its subtree, and configures trace paths.
test/​ztest/​unit/​common/​sof_context.c	Updates the initialization path in a comment.
src/​kernel/​Kconfig	Sources the relocated IDC configuration.
src/​kernel/​init/​README.md	Updates initialization paths and the userspace documentation link.
src/​kernel/​init/​init.c	Relocates firmware initialization code unchanged.
src/​kernel/​init/​ext_manifest.c	Relocates firmware metadata definitions unchanged.
src/​kernel/​init/​CMakeLists.txt	Relocates initialization source registration.
src/​kernel/​idc/​zephyr_idc.c	Relocates Zephyr inter-core messaging unchanged.
src/​kernel/​idc/​README.md	Updates the IDC directory path and documentation link.
src/​kernel/​idc/​Kconfig	Preserves the IDC timeout option at its new location.
src/​kernel/​idc/​idc.c	Relocates IDC command handling unchanged.
src/​kernel/​idc/​CMakeLists.txt	Relocates IDC source registration.
src/​kernel/​CMakeLists.txt	Selects sof_kernel for the IDC and initialization subdirectories.
src/​Kconfig	Replaces the direct IDC include with the kernel configuration entry point.
src/​include/​sof/​userspace/​README.md	Documents the kernel subtree and dedicated library.
src/​audio/​README.md	Updates the kernel-only IDC path.
AGENTS.md	Updates kernel-tier placement guidance for the new layout.

_{Review effort: Balanced}

[intel-sofci]

PR 11398: test results

Run date: 2026-11-04 17:51 UTC

Tested commit: 70ae5693af1b1953d53ce861bbe693aa7f53b77a