WUMSLoader/source/kernel.cpp

#include "kernel.h"
#include "relocator_elf.h"
#include "ElfUtils.h"
#include <coreinit/cache.h>
#include <coreinit/memorymap.h>

extern "C" void SCKernelCopyData(uint32_t addr, uint32_t src, uint32_t len);
extern "C" void SC_KernelCopyData(uint32_t addr, uint32_t src, uint32_t len);

void SetupRelocator() {
    kern_write((void *) (KERN_SYSCALL_TBL_1 + (0x25 * 4)), (unsigned int) SCKernelCopyData);
    kern_write((void *) (KERN_SYSCALL_TBL_2 + (0x25 * 4)), (unsigned int) SCKernelCopyData);
    kern_write((void *) (KERN_SYSCALL_TBL_3 + (0x25 * 4)), (unsigned int) SCKernelCopyData);
    kern_write((void *) (KERN_SYSCALL_TBL_4 + (0x25 * 4)), (unsigned int) SCKernelCopyData);
    kern_write((void *) (KERN_SYSCALL_TBL_5 + (0x25 * 4)), (unsigned int) SCKernelCopyData);

    uint32_t entryPoint = load_loader_elf(0, (char *) relocator_elf, relocator_elf_size);

    unsigned int repl_addr = ADDRESS_main_entry_hook;
    KernelWriteU32(repl_addr, 0x48000003 | entryPoint);
    DCFlushRange((void *) repl_addr, 4);
    ICInvalidateRange((void *) (repl_addr), 4);
}

void KernelWriteU32(uint32_t addr, uint32_t value) {

    ICInvalidateRange(&value, 4);
    DCFlushRange(&value, 4);

    auto dst = (uint32_t) OSEffectiveToPhysical(addr);
    auto src = (uint32_t) OSEffectiveToPhysical((uint32_t) &value);

    SC_KernelCopyData(dst, src, 4);

    DCFlushRange((void *) addr, 4);
    ICInvalidateRange((void *) addr, 4);
}

/* Write a 32-bit word with kernel permissions */
void __attribute__ ((noinline)) kern_write(void *addr, uint32_t value) {
    asm volatile (
    "li 3,1\n"
    "li 4,0\n"
    "mr 5,%1\n"
    "li 6,0\n"
    "li 7,0\n"
    "lis 8,1\n"
    "mr 9,%0\n"
    "mr %1,1\n"
    "li 0,0x3500\n"
    "sc\n"
    "nop\n"
    "mr 1,%1\n"
    :
    :    "r"(addr), "r"(value)
    :    "memory", "ctr", "lr", "0", "3", "4", "5", "6", "7", "8", "9", "10",
    "11", "12"
    );
}