LinxISA musl libc

Scope

lib/musl is the primary libc lane for LinxISA bring-up and SPEC-focused userspace/runtime validation.

Upstream

• Repository: https://github.com/LinxISA/musl
• Merge-back target branch: master

What This Submodule Owns

• LinxISA musl port (arch/linx64)
• Phase-based sysroot generation (phase-a/b/c)
• Bring-up libc used by AVS runtime and SPEC flows

Canonical Build and Test Commands

Run from /Users/zhoubot/linx-isa.

MODE=phase-c bash /Users/zhoubot/linx-isa/lib/musl/tools/linx/build_linx64_musl.sh

python3 /Users/zhoubot/linx-isa/avs/qemu/run_musl_smoke.py \
  --mode phase-c \
  --link both \
  --qemu /Users/zhoubot/linx-isa/emulator/qemu/build/qemu-system-linx64

LinxISA Integration Touchpoints

• Runtime lane and smoke tests in /Users/zhoubot/linx-isa/avs/qemu
• C/C++ runtime overlay generation in /Users/zhoubot/linx-isa/tools/build_linx_llvm_cpp_runtimes.sh
• SPEC toolchain/sysroot dependency path

PTO ISA identity

The Linx loader requires the exact PTO ISA 0.58.3 ELF note before startup, dependency constructors, or dlopen constructors run. Missing notes are rejected by the closure policy; old 0.58.1, malformed, trailing-NUL, and conflicting descriptors fail closed. Byte-identical duplicate notes remain valid.

The ELF descriptor contains only the release ABI fields required by the PTO release manifest. Exact content and source provenance are locked separately in tools/linx/pto_isa_identity.lock.json:

• PTO-SPEC commit e599a3d36ebfad43362ff591ea5e128816c684c7;
• tree abb6899d2e664e378ac9c1b77062670daa4d31b4;
• content SHA-256 f299fe3d256c5d071e57bb4aaa2be2de2e4a386ae090048df1f73ae92d392678;
• encoding projection SHA-256 8a48b80e04484c70870f155bf9efc79d2a805cf99e809f4e4e8a7e6a7eb34172.

Run python3 tools/linx/check_pto_isa_identity.py before any target build. The phase build script records this authority in its summary. It accepts an explicit LLVM_BIN and intentionally does not pin a transient compiler topic commit; release integration supplies the final reviewed toolchain.

Related Docs

• /Users/zhoubot/linx-isa/docs/project/navigation.md
• /Users/zhoubot/linx-isa/docs/bringup/libc_status.md
• /Users/zhoubot/linx-isa/docs/bringup/