[linux-2.6-block.git] / arch / s390 / kernel / early_nobss.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();
}
Commit	Line	Data
971a9ca6 HC	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Copyright IBM Corp. 2007, 2018
	4	*/
	5
	6	/*
	7	* Early setup functions which may not rely on an initialized bss
	8	* section. The last thing that is supposed to happen here is
	9	* initialization of the bss section.
	10	*/
	11
	12	#include <linux/processor.h>
	13	#include <linux/string.h>
	14	#include <asm/sections.h>
	15	#include <asm/lowcore.h>
	16	#include <asm/setup.h>
	17	#include <asm/timex.h>
	18	#include "entry.h"
	19
	20	static void __init reset_tod_clock(void)
	21	{
	22	u64 time;
	23
	24	if (store_tod_clock(&time) == 0)
	25	return;
	26	/* TOD clock not running. Set the clock to Unix Epoch. */
	27	if (set_tod_clock(TOD_UNIX_EPOCH) != 0 \|\| store_tod_clock(&time) != 0)
	28	disabled_wait(0);
	29
	30	memset(tod_clock_base, 0, 16);
	31	(__u64 ) &tod_clock_base[1] = TOD_UNIX_EPOCH;
	32	S390_lowcore.last_update_clock = TOD_UNIX_EPOCH;
	33	}
	34
	35	static void __init rescue_initrd(void)
	36	{
	37	unsigned long min_initrd_addr = (unsigned long) _end + (4UL << 20);
	38
	39	/*
	40	* Just like in case of IPL from VM reader we make sure there is a
	41	* gap of 4MB between end of kernel and start of initrd.
	42	* That way we can also be sure that saving an NSS will succeed,
	43	* which however only requires different segments.
	44	*/
	45	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
	46	return;
	47	if (!INITRD_START \|\| !INITRD_SIZE)
	48	return;
	49	if (INITRD_START >= min_initrd_addr)
	50	return;
	51	memmove((void ) min_initrd_addr, (void ) INITRD_START, INITRD_SIZE);
	52	INITRD_START = min_initrd_addr;
	53	}
	54
	55	static void __init clear_bss_section(void)
	56	{
	57	memset(__bss_start, 0, __bss_stop - __bss_start);
	58	}
	59
	60	void __init startup_init_nobss(void)
	61	{
	62	reset_tod_clock();
	63	rescue_initrd();
	64	clear_bss_section();
65	}