Whispergate-JanusLoader/payload/ecall.hpp

#pragma once
typedef unsigned long long uintptr_t;
typedef unsigned long long uint64_t;

// Inline wrappers for Janus ECALLs from payload code.
// These must stay header-only so the payload has no external deps.

static inline void* janus_get_peb() {
    void* r;
    asm volatile (
        "li a7, 0\n"
        "ecall\n"
        "mv %0, a0\n"
        : "=r"(r) :: "a7", "a0", "memory"
    );
    return r;
}

// fn: function pointer obtained via janus_resolve
// args: array of uintptr_t on the stack, argc: element count
static inline uintptr_t janus_host_call(void* fn, uintptr_t* args, int argc) {
    uintptr_t r;
    asm volatile (
        "li a7, 1\n"
        "mv a0, %1\n"
        "mv a1, %2\n"
        "mv a2, %3\n"
        "ecall\n"
        "mv %0, a0\n"
        : "=r"(r)
        : "r"(fn), "r"(args), "r"((uintptr_t)argc)
        : "a7", "a0", "a1", "a2", "memory"
    );
    return r;
}

static inline void* janus_resolve(const char* mod, const char* sym) {
    void* r;
    asm volatile (
        "li a7, 2\n"
        "mv a0, %1\n"
        "mv a1, %2\n"
        "ecall\n"
        "mv %0, a0\n"
        : "=r"(r)
        : "r"(mod), "r"(sym)
        : "a7", "a0", "a1", "memory"
    );
    return r;
}

static inline void janus_exit(int code) {
    asm volatile (
        "li a7, 3\n"
        "mv a0, %0\n"
        "ecall\n"
        :: "r"((uintptr_t)code) : "a7", "a0", "memory"
    );
}