D297 - External SDK Version Dictionary and Targeted SDK Builds in SELFish and obSCEne

Status: [decided] Date: 2026-09-02 Context: Eliminating 0x80020063 (SCE_KERNEL_ERROR_ESDKVERSION) crashes, replacing magic hex constants with user-friendly string identifiers, and decoupling version tables from source code.

Context

When launching a native PlayStation 5 application on real hardware (FW 12.40), the kernel dynamic loader enforces a minimum SDK version check during module loading. Declaring sdk_version_second = 0 (PPR:00000000) caused sceKernelLoadStartModule to abort process startup immediately with:

[rtld] ERROR self_load_shared_object:2826: B: res 0 (libc.prx) val 2
PRX_SCE_MODULE_LOAD_ERROR (0xa0020102), r12: 0x80020063 (SCE_KERNEL_ERROR_ESDKVERSION)

Arbitrary or hardcoded magic numbers like 0x02000009 are opaque, non-intuitive to users, and inflexible when target platforms or firmware baselines change over time. Furthermore, if a user targets a Gen-4 package (ps4_compat), using a Gen-5 Prospero SDK version is invalid and must be rejected at container build time.

Decision

  1. Decouple SDK Tables into an External Dictionary:

    • Created selfish/data/sdk-versions.toml containing known SDK version mappings, aliases (ps5-native, ps5-current, ps4-compat, zero), target console generations, and descriptions.
    • Users and tools can update or extend this table without recompiling source binaries.

  2. Parse and Validate Target SDKs in SELFish:

    • Implemented selfish-container::sdk::SdkDictionary, supporting loading from custom paths (--sdk-table) or embedded fallbacks.
    • String versions accept dotted notation (e.g. "2.000.009", "8.050.001", "11.600.005"), hex literals (e.g. "0x02000009"), or aliases.
    • Enforce generation compatibility: Gen-5 Prospero versions are rejected when targeting Generation::Previous, and Gen-4-only versions without PPR are rejected for Generation::Current.

  3. ELF PT_SCE_PROCPARAM Segment Patching:

    • patch_elf_procparam() in selfish-container locates the PT_SCE_PROCPARAM segment (p_type == 0x61000001) in uncompressed ELF binaries and stamps both sdk_version (PS4) and sdk_version_second (PPR) before container packing.

  4. Pass --sdk through the Toolchain:

    • Added --sdk <version> to selfish-cli wrap.
    • Added --sdk <version> to obscene-tool mkself.
    • Updated Makefile with: 
      PRIVILEGE ?= app
SDK ?= $(if $(filter 5,$(EBOOT_GEN)),ps5-native,ps4-compat)
    • Updated native: target to default to SDK = ps5-native (0x08050001 / 0x02000009).

Consequences