OpenCloudOS-Kernel/arch/s390/kernel/early_nobss.c

66 lines
1.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2007, 2018
*/
/*
* Early setup functions which may not rely on an initialized bss
* section. The last thing that is supposed to happen here is
* initialization of the bss section.
*/
#include <linux/processor.h>
#include <linux/string.h>
#include <asm/sections.h>
#include <asm/lowcore.h>
#include <asm/setup.h>
#include <asm/timex.h>
#include "entry.h"
static void __init reset_tod_clock(void)
{
u64 time;
if (store_tod_clock(&time) == 0)
return;
/* TOD clock not running. Set the clock to Unix Epoch. */
if (set_tod_clock(TOD_UNIX_EPOCH) != 0 || store_tod_clock(&time) != 0)
disabled_wait(0);
memset(tod_clock_base, 0, 16);
*(__u64 *) &tod_clock_base[1] = TOD_UNIX_EPOCH;
S390_lowcore.last_update_clock = TOD_UNIX_EPOCH;
}
static void __init rescue_initrd(void)
{
unsigned long min_initrd_addr = (unsigned long) _end + (4UL << 20);
/*
* Just like in case of IPL from VM reader we make sure there is a
* gap of 4MB between end of kernel and start of initrd.
* That way we can also be sure that saving an NSS will succeed,
* which however only requires different segments.
*/
if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
return;
if (!INITRD_START || !INITRD_SIZE)
return;
if (INITRD_START >= min_initrd_addr)
return;
memmove((void *) min_initrd_addr, (void *) INITRD_START, INITRD_SIZE);
INITRD_START = min_initrd_addr;
}
static void __init clear_bss_section(void)
{
memset(__bss_start, 0, __bss_stop - __bss_start);
}
void __init startup_init_nobss(void)
{
reset_tod_clock();
rescue_initrd();
clear_bss_section();
}