u-boot/common/board_r.c
Tom Rini 8c98b57d72 Merge patch series "Static initcalls"
Jerome Forissier <jerome.forissier@linaro.org> says:

This series replaces the dynamic initcalls (with function pointers) with
static calls, and gets rid of initcall_run_list(), init_sequence_f,
init_sequence_f_r and init_sequence_r. This makes the code simpler and the
binary slighlty smaller: -2281 bytes/-0.21 % with LTO enabled and -510
bytes/-0.05 % with LTO disabled (xilinx_zynqmp_kria_defconfig).

Execution time doesn't seem to change noticeably. There is no impact on
the SPL.

The inline assembly fixes, although they look unrelated, are triggered
on some platforms with LTO enabled. For example: kirkwood_defconfig.

CI: https://source.denx.de/u-boot/custodians/u-boot-net/-/pipelines/25514

Link: https://lore.kernel.org/r/20250404135038.2134570-1-jerome.forissier@linaro.org
2025-04-14 08:59:45 -06:00

827 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2011 The Chromium OS Authors.
* (C) Copyright 2002-2006
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* (C) Copyright 2002
* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
* Marius Groeger <mgroeger@sysgo.de>
*/
#include <config.h>
#include <api.h>
#include <bootstage.h>
#include <cpu_func.h>
#include <cyclic.h>
#include <display_options.h>
#include <exports.h>
#ifdef CONFIG_MTD_NOR_FLASH
#include <flash.h>
#endif
#include <hang.h>
#include <image.h>
#include <irq_func.h>
#include <lmb.h>
#include <log.h>
#include <net.h>
#include <asm/cache.h>
#include <asm/global_data.h>
#include <u-boot/crc.h>
#include <binman.h>
#include <command.h>
#include <console.h>
#include <dm.h>
#include <efi_loader.h>
#include <env.h>
#include <env_internal.h>
#include <fdtdec.h>
#include <ide.h>
#include <init.h>
#include <initcall.h>
#include <kgdb.h>
#include <irq_func.h>
#include <led.h>
#include <malloc.h>
#include <mapmem.h>
#include <miiphy.h>
#include <mmc.h>
#include <mux.h>
#include <nand.h>
#include <of_live.h>
#include <onenand_uboot.h>
#include <pvblock.h>
#include <scsi.h>
#include <serial.h>
#include <status_led.h>
#include <stdio_dev.h>
#include <timer.h>
#include <trace.h>
#include <watchdog.h>
#include <xen.h>
#include <asm/sections.h>
#include <dm/root.h>
#include <dm/ofnode.h>
#include <linux/compiler.h>
#include <linux/err.h>
#include <wdt.h>
#include <asm-generic/gpio.h>
#include <relocate.h>
DECLARE_GLOBAL_DATA_PTR;
ulong monitor_flash_len;
__weak int board_flash_wp_on(void)
{
/*
* Most flashes can't be detected when write protection is enabled,
* so provide a way to let U-Boot gracefully ignore write protected
* devices.
*/
return 0;
}
__weak int cpu_secondary_init_r(void)
{
return 0;
}
static int initr_trace(void)
{
#ifdef CONFIG_TRACE
trace_init(gd->trace_buff, CONFIG_TRACE_BUFFER_SIZE);
#endif
return 0;
}
static int initr_reloc(void)
{
/* tell others: relocation done */
gd->flags |= GD_FLG_RELOC | GD_FLG_FULL_MALLOC_INIT;
return 0;
}
#if defined(CONFIG_ARM) || defined(CONFIG_RISCV)
/*
* Some of these functions are needed purely because the functions they
* call return void. If we change them to return 0, these stubs can go away.
*/
static int initr_caches(void)
{
/* Enable caches */
enable_caches();
return 0;
}
#endif
__weak int fixup_cpu(void)
{
return 0;
}
static int initr_reloc_global_data(void)
{
#ifdef __ARM__
monitor_flash_len = _end - __image_copy_start;
#elif defined(CONFIG_RISCV)
monitor_flash_len = (ulong)_end - (ulong)_start;
#elif !defined(CONFIG_SANDBOX) && !defined(CONFIG_NIOS2)
monitor_flash_len = (ulong)__init_end - gd->relocaddr;
#endif
#if defined(CONFIG_MPC85xx) || defined(CONFIG_MPC86xx)
/*
* The gd->cpu pointer is set to an address in flash before relocation.
* We need to update it to point to the same CPU entry in RAM.
* TODO: why not just add gd->reloc_ofs?
*/
gd->arch.cpu += gd->relocaddr - CONFIG_SYS_MONITOR_BASE;
/*
* If we didn't know the cpu mask & # cores, we can save them of
* now rather than 'computing' them constantly
*/
fixup_cpu();
#endif
#ifdef CONFIG_SYS_RELOC_GD_ENV_ADDR
/*
* Relocate the early env_addr pointer unless we know it is not inside
* the binary. Some systems need this and for the rest, it doesn't hurt.
*/
gd->env_addr += gd->reloc_off;
#endif
/*
* For CONFIG_OF_EMBED case the FDT is embedded into ELF, available by
* __dtb_dt_begin. After U-Boot ELF self-relocation to RAM top address
* it is worth to update fdt_blob in global_data
*/
if (IS_ENABLED(CONFIG_OF_EMBED))
fdtdec_setup_embed();
#ifdef CONFIG_EFI_LOADER
/*
* On the ARM architecture gd is mapped to a fixed register (r9 or x18).
* As this register may be overwritten by an EFI payload we save it here
* and restore it on every callback entered.
*/
efi_save_gd();
if (!(gd->flags & GD_FLG_SKIP_RELOC))
efi_runtime_relocate(gd->relocaddr, NULL);
#endif
/*
* We are done with all relocations change the permissions of the binary
* NOTE: __start_rodata etc are defined in arm64 linker scripts and
* sections.h. If you want to add support for your platform you need to
* add the symbols on your linker script, otherwise they will point to
* random addresses.
*
*/
if (IS_ENABLED(CONFIG_MMU_PGPROT)) {
pgprot_set_attrs((phys_addr_t)(uintptr_t)(__start_rodata),
(size_t)(uintptr_t)(__end_rodata - __start_rodata),
MMU_ATTR_RO);
pgprot_set_attrs((phys_addr_t)(uintptr_t)(__start_data),
(size_t)(uintptr_t)(__end_data - __start_data),
MMU_ATTR_RW);
pgprot_set_attrs((phys_addr_t)(uintptr_t)(__text_start),
(size_t)(uintptr_t)(__text_end - __text_start),
MMU_ATTR_RX);
}
return 0;
}
__weak int arch_initr_trap(void)
{
return 0;
}
#if defined(CONFIG_SYS_INIT_RAM_LOCK) && defined(CONFIG_E500)
static int initr_unlock_ram_in_cache(void)
{
unlock_ram_in_cache(); /* it's time to unlock D-cache in e500 */
return 0;
}
#endif
static int initr_barrier(void)
{
#ifdef CONFIG_PPC
/* TODO: Can we not use dmb() macros for this? */
asm("sync ; isync");
#endif
return 0;
}
static int initr_malloc(void)
{
ulong start;
#if CONFIG_IS_ENABLED(SYS_MALLOC_F)
debug("Pre-reloc malloc() used %#x bytes (%d KB)\n", gd->malloc_ptr,
gd->malloc_ptr / 1024);
#endif
/* The malloc area is immediately below the monitor copy in DRAM */
/*
* This value MUST match the value of gd->start_addr_sp in board_f.c:
* reserve_noncached().
*/
start = gd->relocaddr - TOTAL_MALLOC_LEN;
gd_set_malloc_start(start);
mem_malloc_init(start, TOTAL_MALLOC_LEN);
return 0;
}
static int initr_of_live(void)
{
if (CONFIG_IS_ENABLED(OF_LIVE)) {
int ret;
bootstage_start(BOOTSTAGE_ID_ACCUM_OF_LIVE, "of_live");
ret = of_live_build(gd->fdt_blob,
(struct device_node **)gd_of_root_ptr());
bootstage_accum(BOOTSTAGE_ID_ACCUM_OF_LIVE);
if (ret)
return ret;
}
return 0;
}
#ifdef CONFIG_DM
static int initr_dm(void)
{
int ret;
oftree_reset();
/* Drop the pre-reloc driver model and start a new one */
gd->dm_root = NULL;
#ifdef CONFIG_TIMER
gd->timer = NULL;
#endif
bootstage_start(BOOTSTAGE_ID_ACCUM_DM_R, "dm_r");
ret = dm_init_and_scan(false);
bootstage_accum(BOOTSTAGE_ID_ACCUM_DM_R);
if (ret)
return ret;
return dm_autoprobe();
}
#endif
static int initr_dm_devices(void)
{
int ret;
if (IS_ENABLED(CONFIG_TIMER_EARLY)) {
ret = dm_timer_init();
if (ret)
return ret;
}
if (IS_ENABLED(CONFIG_MULTIPLEXER)) {
/*
* Initialize the multiplexer controls to their default state.
* This must be done early as other drivers may unknowingly
* rely on it.
*/
ret = dm_mux_init();
if (ret)
return ret;
}
return 0;
}
static int initr_bootstage(void)
{
bootstage_mark_name(BOOTSTAGE_ID_START_UBOOT_R, "board_init_r");
return 0;
}
__weak int power_init_board(void)
{
return 0;
}
static int initr_announce(void)
{
debug("Now running in RAM - U-Boot at: %08lx\n", gd->relocaddr);
return 0;
}
static int __maybe_unused initr_binman(void)
{
int ret;
ret = binman_init();
if (ret)
printf("binman_init failed:%d\n", ret);
return ret;
}
#if defined(CONFIG_MTD_NOR_FLASH)
__weak int is_flash_available(void)
{
return 1;
}
static int initr_flash(void)
{
ulong flash_size = 0;
struct bd_info *bd = gd->bd;
if (!is_flash_available())
return 0;
puts("Flash: ");
if (board_flash_wp_on())
printf("Uninitialized - Write Protect On\n");
else
flash_size = flash_init();
print_size(flash_size, "");
#ifdef CONFIG_SYS_FLASH_CHECKSUM
/*
* Compute and print flash CRC if flashchecksum is set to 'y'
*
* NOTE: Maybe we should add some schedule()? XXX
*/
if (env_get_yesno("flashchecksum") == 1) {
const uchar *flash_base = (const uchar *)CFG_SYS_FLASH_BASE;
printf(" CRC: %08X", crc32(0,
flash_base,
flash_size));
}
#endif /* CONFIG_SYS_FLASH_CHECKSUM */
putc('\n');
/* update start of FLASH memory */
#ifdef CFG_SYS_FLASH_BASE
bd->bi_flashstart = CFG_SYS_FLASH_BASE;
#endif
/* size of FLASH memory (final value) */
bd->bi_flashsize = flash_size;
#if defined(CONFIG_SYS_UPDATE_FLASH_SIZE)
/* Make a update of the Memctrl. */
update_flash_size(flash_size);
#endif
#if defined(CONFIG_OXC) || defined(CONFIG_RMU)
/* flash mapped at end of memory map */
bd->bi_flashoffset = CONFIG_TEXT_BASE + flash_size;
#elif CONFIG_SYS_MONITOR_BASE == CFG_SYS_FLASH_BASE
bd->bi_flashoffset = monitor_flash_len; /* reserved area for monitor */
#endif
return 0;
}
#endif
#ifdef CONFIG_CMD_NAND
/* go init the NAND */
static int initr_nand(void)
{
puts("NAND: ");
nand_init();
printf("%lu MiB\n", nand_size() / 1024);
return 0;
}
#endif
#if defined(CONFIG_CMD_ONENAND)
/* go init the NAND */
static int initr_onenand(void)
{
puts("NAND: ");
onenand_init();
return 0;
}
#endif
#ifdef CONFIG_MMC
static int initr_mmc(void)
{
puts("MMC: ");
mmc_initialize(gd->bd);
return 0;
}
#endif
#ifdef CONFIG_PVBLOCK
static int initr_pvblock(void)
{
puts("PVBLOCK: ");
pvblock_init();
return 0;
}
#endif
/*
* Tell if it's OK to load the environment early in boot.
*
* If CONFIG_OF_CONTROL is defined, we'll check with the FDT to see
* if this is OK (defaulting to saying it's OK).
*
* NOTE: Loading the environment early can be a bad idea if security is
* important, since no verification is done on the environment.
*
* Return: 0 if environment should not be loaded, !=0 if it is ok to load
*/
static int should_load_env(void)
{
if (IS_ENABLED(CONFIG_OF_CONTROL))
return ofnode_conf_read_int("load-environment", 1);
if (IS_ENABLED(CONFIG_DELAY_ENVIRONMENT))
return 0;
return 1;
}
static int initr_env(void)
{
/* initialize environment */
if (should_load_env())
env_relocate();
else
env_set_default(NULL, 0);
env_import_fdt();
if (IS_ENABLED(CONFIG_OF_CONTROL))
env_set_hex("fdtcontroladdr",
(unsigned long)map_to_sysmem(gd->fdt_blob));
#if (IS_ENABLED(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR) || \
IS_ENABLED(CONFIG_SAVE_PREV_BL_FDT_ADDR))
save_prev_bl_data();
#endif
/* Initialize from environment */
image_load_addr = env_get_ulong("loadaddr", 16, image_load_addr);
return 0;
}
#ifdef CONFIG_SYS_MALLOC_BOOTPARAMS
static int initr_malloc_bootparams(void)
{
gd->bd->bi_boot_params = (ulong)malloc(CONFIG_SYS_BOOTPARAMS_LEN);
if (!gd->bd->bi_boot_params) {
puts("WARNING: Cannot allocate space for boot parameters\n");
return -ENOMEM;
}
return 0;
}
#endif
static int initr_status_led(void)
{
status_led_init();
return 0;
}
static int initr_boot_led_blink(void)
{
status_led_boot_blink();
led_boot_blink();
return 0;
}
static int initr_boot_led_on(void)
{
led_boot_on();
return 0;
}
#if defined(CONFIG_CMD_NET)
static int initr_net(void)
{
puts("Net: ");
eth_initialize();
#if defined(CONFIG_RESET_PHY_R)
debug("Reset Ethernet PHY\n");
reset_phy();
#endif
return 0;
}
#endif
#ifdef CONFIG_POST
static int initr_post(void)
{
post_run(NULL, POST_RAM | post_bootmode_get(0));
return 0;
}
#endif
#if defined(CFG_PRAM)
/*
* Export available size of memory for Linux, taking into account the
* protected RAM at top of memory
*/
int initr_mem(void)
{
ulong pram = 0;
char memsz[32];
pram = env_get_ulong("pram", 10, CFG_PRAM);
sprintf(memsz, "%ldk", (long int)((gd->ram_size / 1024) - pram));
env_set("mem", memsz);
return 0;
}
#endif
static int initr_lmb(void)
{
if (CONFIG_IS_ENABLED(LMB))
return lmb_init();
else
return 0;
}
static int dm_announce(void)
{
int device_count;
int uclass_count;
if (IS_ENABLED(CONFIG_DM)) {
dm_get_stats(&device_count, &uclass_count);
printf("Core: %d devices, %d uclasses", device_count,
uclass_count);
if (CONFIG_IS_ENABLED(OF_REAL))
printf(", devicetree: %s", fdtdec_get_srcname());
if (CONFIG_IS_ENABLED(UPL))
printf(", universal payload active");
printf("\n");
if (IS_ENABLED(CONFIG_OF_HAS_PRIOR_STAGE) &&
(gd->fdt_src == FDTSRC_SEPARATE ||
gd->fdt_src == FDTSRC_EMBED)) {
printf("Warning: Unexpected devicetree source (not from a prior stage)");
printf("Warning: U-Boot may not function properly\n");
}
if (IS_ENABLED(CONFIG_OF_TAG_MIGRATE) &&
(gd->flags & GD_FLG_OF_TAG_MIGRATE))
/*
* U-Boot will silently fail to work after 2023.07 if
* there are old tags present
*/
printf("Warning: Device tree includes old 'u-boot,dm-' tags: please fix by 2023.07!\n");
}
return 0;
}
static int run_main_loop(void)
{
#ifdef CONFIG_SANDBOX
sandbox_main_loop_init();
#endif
event_notify_null(EVT_MAIN_LOOP);
/* main_loop() can return to retry autoboot, if so just run it again */
for (;;)
main_loop();
return 0;
}
/*
* Over time we hope to remove most of the driver-related init and do it
* if/when the driver is later used.
*
* TODO: perhaps reset the watchdog in the initcall function after each call?
*/
static void initcall_run_r(void)
{
/*
* Please do not add logic to this function (variables, if (), etc.).
* For simplicity it should remain an ordered list of function calls.
*/
INITCALL(initr_trace);
INITCALL(initr_reloc);
INITCALL(event_init);
/* TODO: could x86/PPC have this also perhaps? */
#if CONFIG_IS_ENABLED(ARM) || CONFIG_IS_ENABLED(RISCV)
INITCALL(initr_caches);
/* Note: For Freescale LS2 SoCs, new MMU table is created in DDR.
* A temporary mapping of IFC high region is since removed,
* so environmental variables in NOR flash is not available
* until board_init() is called below to remap IFC to high
* region.
*/
#endif
INITCALL(initr_reloc_global_data);
#if CONFIG_IS_ENABLED(SYS_INIT_RAM_LOCK) && CONFIG_IS_ENABLED(E500)
INITCALL(initr_unlock_ram_in_cache);
#endif
INITCALL(initr_barrier);
INITCALL(initr_malloc);
INITCALL(log_init);
INITCALL(initr_bootstage); /* Needs malloc() but has its own timer */
#if CONFIG_IS_ENABLED(CONSOLE_RECORD)
INITCALL(console_record_init);
#endif
#if CONFIG_IS_ENABLED(SYS_NONCACHED_MEMORY)
INITCALL(noncached_init);
#endif
INITCALL(initr_of_live);
#if CONFIG_IS_ENABLED(DM)
INITCALL(initr_dm);
#endif
#if CONFIG_IS_ENABLED(ADDR_MAP)
INITCALL(init_addr_map);
#endif
#if CONFIG_IS_ENABLED(ARM) || CONFIG_IS_ENABLED(RISCV) || \
CONFIG_IS_ENABLED(SANDBOX)
INITCALL(board_init); /* Setup chipselects */
#endif
/*
* TODO: printing of the clock inforamtion of the board is now
* implemented as part of bdinfo command. Currently only support for
* davinci SOC's is added. Remove this check once all the board
* implement this.
*/
#if CONFIG_IS_ENABLED(CLOCKS)
INITCALL(set_cpu_clk_info);
#endif
INITCALL(initr_lmb);
#if CONFIG_IS_ENABLED(EFI_LOADER)
INITCALL(efi_memory_init);
#endif
#if CONFIG_IS_ENABLED(BINMAN_FDT)
INITCALL(initr_binman);
#endif
#if CONFIG_IS_ENABLED(FSP_VERSION2)
INITCALL(arch_fsp_init_r);
#endif
INITCALL(initr_dm_devices);
INITCALL(stdio_init_tables);
INITCALL(serial_initialize);
INITCALL(initr_announce);
INITCALL(dm_announce);
#if CONFIG_IS_ENABLED(WDT)
INITCALL(initr_watchdog);
#endif
WATCHDOG_RESET();
INITCALL(arch_initr_trap);
#if CONFIG_IS_ENABLED(BOARD_EARLY_INIT_R)
INITCALL(board_early_init_r);
#endif
WATCHDOG_RESET();
#if CONFIG_IS_ENABLED(POST)
INITCALL(post_output_backlog);
#endif
WATCHDOG_RESET();
#if CONFIG_IS_ENABLED(PCI_INIT_R) && CONFIG_IS_ENABLED(SYS_EARLY_PCI_INIT)
/*
* Do early PCI configuration _before_ the flash gets initialised,
* because PCU resources are crucial for flash access on some boards.
*/
INITCALL(pci_init);
#endif
#if CONFIG_IS_ENABLED(ARCH_EARLY_INIT_R)
INITCALL(arch_early_init_r);
#endif
INITCALL(power_init_board);
#if CONFIG_IS_ENABLED(MTD_NOR_FLASH)
INITCALL(initr_flash);
#endif
WATCHDOG_RESET();
#if CONFIG_IS_ENABLED(PPC) || CONFIG_IS_ENABLED(M68K) || CONFIG_IS_ENABLED(X86)
/* initialize higher level parts of CPU like time base and timers */
INITCALL(cpu_init_r);
#endif
#if CONFIG_IS_ENABLED(EFI_LOADER)
INITCALL(efi_init_early);
#endif
#if CONFIG_IS_ENABLED(CMD_NAND)
INITCALL(initr_nand);
#endif
#if CONFIG_IS_ENABLED(CMD_ONENAND)
INITCALL(initr_onenand);
#endif
#if CONFIG_IS_ENABLED(MMC)
INITCALL(initr_mmc);
#endif
#if CONFIG_IS_ENABLED(XEN)
INITCALL(xen_init);
#endif
#if CONFIG_IS_ENABLED(PVBLOCK)
INITCALL(initr_pvblock);
#endif
INITCALL(initr_env);
#if CONFIG_IS_ENABLED(SYS_MALLOC_BOOTPARAMS)
INITCALL(initr_malloc_bootparams);
#endif
WATCHDOG_RESET();
INITCALL(cpu_secondary_init_r);
#if CONFIG_IS_ENABLED(ID_EEPROM)
INITCALL(mac_read_from_eeprom);
#endif
INITCALL_EVT(EVT_SETTINGS_R);
WATCHDOG_RESET();
#if CONFIG_IS_ENABLED(PCI_INIT_R) && !CONFIG_IS_ENABLED(SYS_EARLY_PCI_INIT)
/*
* Do pci configuration
*/
INITCALL(pci_init);
#endif
INITCALL(stdio_add_devices);
INITCALL(jumptable_init);
#if CONFIG_IS_ENABLED(API)
INITCALL(api_init);
#endif
INITCALL(console_init_r); /* fully init console as a device */
#if CONFIG_IS_ENABLED(DISPLAY_BOARDINFO_LATE)
INITCALL(console_announce_r);
INITCALL(show_board_info);
#endif
/* miscellaneous arch-dependent init */
#if CONFIG_IS_ENABLED(ARCH_MISC_INIT)
INITCALL(arch_misc_init);
#endif
/* miscellaneous platform-dependent init */
#if CONFIG_IS_ENABLED(MISC_INIT_R)
INITCALL(misc_init_r);
#endif
WATCHDOG_RESET();
#if CONFIG_IS_ENABLED(CMD_KGDB)
INITCALL(kgdb_init);
#endif
INITCALL(interrupt_init);
#if defined(CONFIG_MICROBLAZE) || defined(CONFIG_M68K)
INITCALL(timer_init); /* initialize timer */
#endif
INITCALL(initr_status_led);
INITCALL(initr_boot_led_blink);
/* PPC has a udelay(20) here dating from 2002. Why? */
#if CONFIG_IS_ENABLED(BOARD_LATE_INIT)
INITCALL(board_late_init);
#endif
#if CONFIG_IS_ENABLED(PCI_ENDPOINT)
INITCALL(pci_ep_init);
#endif
#if CONFIG_IS_ENABLED(CMD_NET)
WATCHDOG_RESET();
INITCALL(initr_net);
#endif
#if CONFIG_IS_ENABLED(POST)
INITCALL(initr_post);
#endif
WATCHDOG_RESET();
INITCALL_EVT(EVT_LAST_STAGE_INIT);
#if defined(CFG_PRAM)
INITCALL(initr_mem);
#endif
INITCALL(initr_boot_led_on);
INITCALL(run_main_loop);
}
void board_init_r(gd_t *new_gd, ulong dest_addr)
{
/*
* The pre-relocation drivers may be using memory that has now gone
* away. Mark serial as unavailable - this will fall back to the debug
* UART if available.
*
* Do the same with log drivers since the memory may not be available.
*/
gd->flags &= ~(GD_FLG_SERIAL_READY | GD_FLG_LOG_READY);
/*
* Set up the new global data pointer. So far only x86 does this
* here.
* TODO(sjg@chromium.org): Consider doing this for all archs, or
* dropping the new_gd parameter.
*/
if (CONFIG_IS_ENABLED(X86_64) && !IS_ENABLED(CONFIG_EFI_APP))
arch_setup_gd(new_gd);
#if !defined(CONFIG_X86) && !defined(CONFIG_ARM) && !defined(CONFIG_ARM64)
gd = new_gd;
#endif
gd->flags &= ~GD_FLG_LOG_READY;
initcall_run_r();
/* NOTREACHED - run_main_loop() does not return */
hang();
}