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Commit 978fa72e authored by Heiko Carstens's avatar Heiko Carstens
Browse files

s390: remove named saved segment support 



Remove the support to create a z/VM named saved segment (NSS). This
feature is not supported since quite a while in favour of jump labels,
function tracing and (now) CPU alternatives. All of these features
require to write to the kernel text section which is not possible if
the kernel is contained within an NSS.

Given that memory savings are minimal if kernel images are shared and
in addition updates of shared images are painful, the NSS feature can
be removed.

Reviewed-by: default avatarHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent f44fa887

arch/s390/Kconfig

+0 −13
Original line number Diff line number Diff line
@@ -824,19 +824,6 @@ config PFAULT 
	  Everybody who wants to run Linux under VM != VM4.2 should select

	  this option.



config SHARED_KERNEL

	bool "VM shared kernel support"

	depends on !JUMP_LABEL

	depends on !ALTERNATIVES

	help

	  Select this option, if you want to share the text segment of the

	  Linux kernel between different VM guests. This reduces memory

	  usage with lots of guests but greatly increases kernel size.

	  Also if a kernel was IPL'ed from a shared segment the kexec system

	  call will not work.

	  You should only select this option if you know what you are

	  doing and want to exploit this feature.



config CMM

	def_tristate n

	prompt "Cooperative memory management"

arch/s390/include/asm/ipl.h

+2 −1
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include <asm/cio.h>

#include <asm/setup.h>



#define NSS_NAME_SIZE	8



#define IPL_PARMBLOCK_ORIGIN	0x2000



#define IPL_PARM_BLK_FCP_LEN (sizeof(struct ipl_list_hdr) + \
@@ -105,7 +107,6 @@ extern size_t append_ipl_scpdata(char *, size_t); 
enum {

	IPL_DEVNO_VALID		= 1,

	IPL_PARMBLOCK_VALID	= 2,

	IPL_NSS_VALID		= 4,

};



enum ipl_type {

arch/s390/include/asm/sections.h

+1 −1
Original line number Diff line number Diff line
@@ -3,6 +3,6 @@ 


#include <asm-generic/sections.h>



extern char _eshared[], _ehead[];

extern char _ehead[];



#endif

arch/s390/include/asm/setup.h

+0 −3
Original line number Diff line number Diff line
@@ -97,9 +97,6 @@ extern char vmpoff_cmd[]; 
#define SET_CONSOLE_VT220	do { console_mode = 4; } while (0)

#define SET_CONSOLE_HVC		do { console_mode = 5; } while (0)



#define NSS_NAME_SIZE	8

extern char kernel_nss_name[];



#ifdef CONFIG_PFAULT

extern int pfault_init(void);

extern void pfault_fini(void);

arch/s390/kernel/early.c

+0 −141
Original line number Diff line number Diff line
@@ -30,14 +30,6 @@ 
#include <asm/facility.h>

#include "entry.h"



/*

 * Create a Kernel NSS if the SAVESYS= parameter is defined

 */

#define DEFSYS_CMD_SIZE		128

#define SAVESYS_CMD_SIZE	32



char kernel_nss_name[NSS_NAME_SIZE + 1];



static void __init setup_boot_command_line(void);



/*
@@ -58,134 +50,6 @@ static void __init reset_tod_clock(void) 
	S390_lowcore.last_update_clock = TOD_UNIX_EPOCH;

}



#ifdef CONFIG_SHARED_KERNEL

int __init savesys_ipl_nss(char *cmd, const int cmdlen);



asm(

	"	.section .init.text,\"ax\",@progbits\n"

	"	.align	4\n"

	"	.type	savesys_ipl_nss, @function\n"

	"savesys_ipl_nss:\n"

	"	stmg	6,15,48(15)\n"

	"	lgr	14,3\n"

	"	sam31\n"

	"	diag	2,14,0x8\n"

	"	sam64\n"

	"	lgr	2,14\n"

	"	lmg	6,15,48(15)\n"

	"	br	14\n"

	"	.size	savesys_ipl_nss, .-savesys_ipl_nss\n"

	"	.previous\n");



static __initdata char upper_command_line[COMMAND_LINE_SIZE];



static noinline __init void create_kernel_nss(void)

{

	unsigned int i, stext_pfn, eshared_pfn, end_pfn, min_size;

#ifdef CONFIG_BLK_DEV_INITRD

	unsigned int sinitrd_pfn, einitrd_pfn;

#endif

	int response;

	int hlen;

	size_t len;

	char *savesys_ptr;

	char defsys_cmd[DEFSYS_CMD_SIZE];

	char savesys_cmd[SAVESYS_CMD_SIZE];



	/* Do nothing if we are not running under VM */

	if (!MACHINE_IS_VM)

		return;



	/* Convert COMMAND_LINE to upper case */

	for (i = 0; i < strlen(boot_command_line); i++)

		upper_command_line[i] = toupper(boot_command_line[i]);



	savesys_ptr = strstr(upper_command_line, "SAVESYS=");



	if (!savesys_ptr)

		return;



	savesys_ptr += 8;    /* Point to the beginning of the NSS name */

	for (i = 0; i < NSS_NAME_SIZE; i++) {

		if (savesys_ptr[i] == ' ' || savesys_ptr[i] == '\0')

			break;

		kernel_nss_name[i] = savesys_ptr[i];

	}



	stext_pfn = PFN_DOWN(__pa(&_stext));

	eshared_pfn = PFN_DOWN(__pa(&_eshared));

	end_pfn = PFN_UP(__pa(&_end));

	min_size = end_pfn << 2;



	hlen = snprintf(defsys_cmd, DEFSYS_CMD_SIZE,

			"DEFSYS %s 00000-%.5X EW %.5X-%.5X SR %.5X-%.5X",

			kernel_nss_name, stext_pfn - 1, stext_pfn,

			eshared_pfn - 1, eshared_pfn, end_pfn);



#ifdef CONFIG_BLK_DEV_INITRD

	if (INITRD_START && INITRD_SIZE) {

		sinitrd_pfn = PFN_DOWN(__pa(INITRD_START));

		einitrd_pfn = PFN_UP(__pa(INITRD_START + INITRD_SIZE));

		min_size = einitrd_pfn << 2;

		hlen += snprintf(defsys_cmd + hlen, DEFSYS_CMD_SIZE - hlen,

				 " EW %.5X-%.5X", sinitrd_pfn, einitrd_pfn);

	}

#endif



	snprintf(defsys_cmd + hlen, DEFSYS_CMD_SIZE - hlen,

		 " EW MINSIZE=%.7iK PARMREGS=0-13", min_size);

	defsys_cmd[DEFSYS_CMD_SIZE - 1] = '\0';

	snprintf(savesys_cmd, SAVESYS_CMD_SIZE, "SAVESYS %s \n IPL %s",

		 kernel_nss_name, kernel_nss_name);

	savesys_cmd[SAVESYS_CMD_SIZE - 1] = '\0';



	__cpcmd(defsys_cmd, NULL, 0, &response);



	if (response != 0) {

		pr_err("Defining the Linux kernel NSS failed with rc=%d\n",

			response);

		kernel_nss_name[0] = '\0';

		return;

	}



	len = strlen(savesys_cmd);

	ASCEBC(savesys_cmd, len);

	response = savesys_ipl_nss(savesys_cmd, len);



	/* On success: response is equal to the command size,

	 *	       max SAVESYS_CMD_SIZE

	 * On error: response contains the numeric portion of cp error message.

	 *	     for SAVESYS it will be >= 263

	 *	     for missing privilege class, it will be 1

	 */

	if (response > SAVESYS_CMD_SIZE || response == 1) {

		pr_err("Saving the Linux kernel NSS failed with rc=%d\n",

			response);

		kernel_nss_name[0] = '\0';

		return;

	}



	/* re-initialize cputime accounting. */

	get_tod_clock_ext(tod_clock_base);

	S390_lowcore.last_update_clock = *(__u64 *) &tod_clock_base[1];

	S390_lowcore.last_update_timer = 0x7fffffffffffffffULL;

	S390_lowcore.user_timer = 0;

	S390_lowcore.system_timer = 0;

	asm volatile("SPT 0(%0)" : : "a" (&S390_lowcore.last_update_timer));



	/* re-setup boot command line with new ipl vm parms */

	ipl_update_parameters();

	setup_boot_command_line();



	ipl_flags = IPL_NSS_VALID;

}



#else /* CONFIG_SHARED_KERNEL */



static inline void create_kernel_nss(void) { }



#endif /* CONFIG_SHARED_KERNEL */



/*

 * Clear bss memory

 */
@@ -548,10 +412,6 @@ static void __init setup_boot_command_line(void) 
	append_to_cmdline(append_ipl_scpdata);

}



/*

 * Save ipl parameters, clear bss memory, initialize storage keys

 * and create a kernel NSS at startup if the SAVESYS= parm is defined

 */

void __init startup_init(void)

{

	reset_tod_clock();
@@ -568,7 +428,6 @@ void __init startup_init(void) 
	setup_arch_string();

	ipl_update_parameters();

	setup_boot_command_line();

	create_kernel_nss();

	detect_diag9c();

	detect_diag44();

	detect_machine_facilities();