MissionControl/applet/source/reboot.c

#include <stdio.h>
#include <string.h>
#include <switch.h>

#define IRAM_PAYLOAD_MAX_SIZE 0x2F000
#define IRAM_PAYLOAD_BASE 0x40010000

static alignas(0x1000) u8 g_reboot_payload[IRAM_PAYLOAD_MAX_SIZE];
static alignas(0x1000) u8 g_ff_page[0x1000];
static alignas(0x1000) u8 g_work_page[0x1000];

void do_iram_dram_copy(void *buf, uintptr_t iram_addr, size_t size, int option) {
    memcpy(g_work_page, buf, size);
    
    SecmonArgs args = {0};
    args.X[0] = 0xF0000201;             /* smcAmsIramCopy */
    args.X[1] = (uintptr_t)g_work_page;  /* DRAM Address */
    args.X[2] = iram_addr;              /* IRAM Address */
    args.X[3] = size;                   /* Copy size */
    args.X[4] = option;                 /* 0 = Read, 1 = Write */
    svcCallSecureMonitor(&args);
    
    memcpy(buf, g_work_page, size);
}

void copy_to_iram(uintptr_t iram_addr, void *buf, size_t size) {
    do_iram_dram_copy(buf, iram_addr, size, 1);
}

void copy_from_iram(void *buf, uintptr_t iram_addr, size_t size) {
    do_iram_dram_copy(buf, iram_addr, size, 0);
}

static void clear_iram(void) {
    memset(g_ff_page, 0xFF, sizeof(g_ff_page));
    for (size_t i = 0; i < IRAM_PAYLOAD_MAX_SIZE; i += sizeof(g_ff_page)) {
        copy_to_iram(IRAM_PAYLOAD_BASE + i, g_ff_page, sizeof(g_ff_page));
    }
}

static void reboot_to_payload(void) {
    clear_iram();
    
    for (size_t i = 0; i < IRAM_PAYLOAD_MAX_SIZE; i += 0x1000) {
        copy_to_iram(IRAM_PAYLOAD_BASE + i, &g_reboot_payload[i], 0x1000);
    }
    
    splSetConfig((SplConfigItem)65001, 2);
}

void reboot(void) {
    FILE *f = fopen("sdmc:/atmosphere/reboot_payload.bin", "rb");
    if (f != NULL) {
        fread(g_reboot_payload, 1, sizeof(g_reboot_payload), f);
        fclose(f);

        reboot_to_payload();
    }
}