Loader

Generates loader assembly code for initializing the test runtime environment. Boots at _start in machine mode, initializes registers (integer, floating-point, vector if supported) and CSRs, sets up paging and interrupts, and hands control to the scheduler.

Interface

The loader interface defines the following routines:

_start

Entry point required by the linker. Sets up integer GPRs and initial panic. Any traps that occur before the loader sets up the trap handler will jump to eot__failed to end the test.

loader__initialize_runtime

Initializes runtime environment by setting up CSRs, paging, trap delegation, and privilege mode. Any traps that occurs after mtvec has been set will jump to eot__test_end to end the test. Includes any PRE_LOADER hooks that have been registered.

loader__done

Starts scheduler by jumping to scheduler__init. Includes any POST_LOADER hooks that have been registered.

loader_panic

Panic routine to jump directly to eot__failed and end the test as a fail. This assumes that the current privilege is M mode and bypasses eot__end_test sequence.

Note

Traps that occur after mtvec has been set will jump through trap_handler instead, and finish with eot__end_test.

        graph LR
    start[_start]
    panic[loader__panic]
    init[loader__initialize_runtime]
    done[loader__done]
    scheduler[scheduler__init]
    eot[eot__fail]


    start --> init
    start -->|trap| panic
    init --> done
    init -->|trap| panic
    done --> scheduler

    panic --> eot



    classDef mMode fill:#5164e0,stroke:#5164e0,stroke-width:3px,color:#fff
    classDef handlerMode fill:#fa512e,stroke:#fa512e,stroke-width:3px,color:#000
    classDef handlerBlock fill:#FEC3A4,stroke:#FEC3A4,stroke-width:3px,color:#0
    classDef testMode fill:#7584e6,stroke:#7584e6,stroke-width:3px,color:#0
    classDef testBlock fill:#C0C0E0,stroke:#C0C0E0,stroke-width:3px,color:#0

    class start,init,eot,panic mMode
    class done,scheduler handlerMode
    class syscall_f0000002,syscall_f0000003,failed,end_test handlerBlock

Linux Mode

The linux loader targets application code is enabled with the linux_mode feature. It is used to run tests in linux mode and skips all setup code to jump to scheduler__init.

wysiwyg mode

Returns the loader used for What You See Is What You Get (wysiwyg) mode.

Since wysiwyg mode doesn’t have a scheduler, the loader just initializes the GPRs and any init_csr_code and continues to test.

Configuration

  • priv_mode: Target privilege mode

  • paging_mode: Paging mode to enable (SV39, SV48, SV57)

  • bringup_pagetables: Skip scheduler and jump directly to first test

  • linux_mode: Enable Linux loader mode

  • wysiwyg: Minimal loader without runtime setup

  • big_endian: Enable big-endian mode

  • csr_init: List of CSRs to initialize (format: csr=value)

  • csr_init_mask: List of CSRs to initialize with mask (format: csr=mask=value)

  • counter_event_path: Path to event file for enabling performance counters

  • disable_wfi_wait: Disable WFI waiting

  • needs_pma: Setup PMA regions

  • setup_pmp: Setup PMP regions

  • secure_mode: Enable secure mode

  • setup_stateen: Setup mstateen registers

  • env: Test environment (TEST_ENV_VIRTUALIZED or standard)

  • senvcfg: Value to write to senvcfg

  • trap_handler_label: Label for trap handler entry point

  • interrupts_enabled: Enable interrupts

  • deleg_excp_to: Delegate exceptions to privilege level

  • pbmt_ncio: Enable SVPBMT NCIO

  • svadu: Enable SVADU extension

  • menvcfg: Value to OR with default menvcfg

  • medeleg: Custom medeleg value

  • user_interrupt_table: Use user-defined interrupt table