arch/sparc/kernel/setup.c - linux/kernel/git/mellanox/linux - Git at Google

 /*  $Id: setup.c,v 1.126 2001/11/13 00:49:27 davem Exp $
  *  linux/arch/sparc/kernel/setup.c
  *
  *  Copyright (C) 1995  David S. Miller (davem@caip.rutgers.edu)
  *  Copyright (C) 2000  Anton Blanchard (anton@samba.org)
  */

 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/stddef.h>
 #include <linux/unistd.h>
 #include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <linux/initrd.h>
 #include <asm/smp.h>
 #include <linux/user.h>
 #include <linux/a.out.h>
 #include <linux/screen_info.h>
 #include <linux/delay.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
 #include <linux/syscalls.h>
 #include <linux/kdev_t.h>
 #include <linux/major.h>
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/console.h>
 #include <linux/spinlock.h>
 #include <linux/root_dev.h>
 #include <linux/cpu.h>
 #include <linux/kdebug.h>

 #include <asm/system.h>
 #include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/oplib.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/traps.h>
 #include <asm/vaddrs.h>
 #include <asm/mbus.h>
 #include <asm/idprom.h>
 #include <asm/machines.h>
 #include <asm/cpudata.h>
 #include <asm/setup.h>

 struct screen_info screen_info = {
 	0, 0,			/* orig-x, orig-y */
 	0,			/* unused */
 	0,			/* orig-video-page */
 	0,			/* orig-video-mode */
 	128,			/* orig-video-cols */
 	0,0,0,			/* ega_ax, ega_bx, ega_cx */
 	54,			/* orig-video-lines */
 	0,                      /* orig-video-isVGA */
 	16                      /* orig-video-points */
 };

 /* Typing sync at the prom prompt calls the function pointed to by
  * romvec->pv_synchook which I set to the following function.
  * This should sync all filesystems and return, for now it just
  * prints out pretty messages and returns.
  */

 extern unsigned long trapbase;
 void (*prom_palette)(int);

 /* Pretty sick eh? */
 void prom_sync_me(void)
 {
 	unsigned long prom_tbr, flags;

 	/* XXX Badly broken. FIX! - Anton */
 	local_irq_save(flags);
 	__asm__ __volatile__("rd %%tbr, %0\n\t" : "=r" (prom_tbr));
 	__asm__ __volatile__("wr %0, 0x0, %%tbr\n\t"
 			     "nop\n\t"
 			     "nop\n\t"
 			     "nop\n\t" : : "r" (&trapbase));

 	if (prom_palette)
 		prom_palette(1);
 	prom_printf("PROM SYNC COMMAND...\n");
 	show_free_areas();
 	if(current->pid != 0) {
 		local_irq_enable();
 		sys_sync();
 		local_irq_disable();
 	}
 	prom_printf("Returning to prom\n");

 	__asm__ __volatile__("wr %0, 0x0, %%tbr\n\t"
 			     "nop\n\t"
 			     "nop\n\t"
 			     "nop\n\t" : : "r" (prom_tbr));
 	local_irq_restore(flags);

 	return;
 }

 unsigned int boot_flags __initdata = 0;
 #define BOOTME_DEBUG  0x1

 /* Exported for mm/init.c:paging_init. */
 unsigned long cmdline_memory_size __initdata = 0;

 static void
 prom_console_write(struct console *con, const char *s, unsigned n)
 {
 	prom_write(s, n);
 }

 static struct console prom_debug_console = {
 	.name =		"debug",
 	.write =	prom_console_write,
 	.flags =	CON_PRINTBUFFER,
 	.index =	-1,
 };

 /*
  * Process kernel command line switches that are specific to the
  * SPARC or that require special low-level processing.
  */
 static void __init process_switch(char c)
 {
 	switch (c) {
 	case 'd':
 		boot_flags |= BOOTME_DEBUG;
 		break;
 	case 's':
 		break;
 	case 'h':
 		prom_printf("boot_flags_init: Halt!\n");
 		prom_halt();
 		break;
 	case 'p':
 		/* Use PROM debug console. */
 		register_console(&prom_debug_console);
 		break;
 	default:
 		printk("Unknown boot switch (-%c)\n", c);
 		break;
 	}
 }

 static void __init boot_flags_init(char *commands)
 {
 	while (*commands) {
 		/* Move to the start of the next "argument". */
 		while (*commands && *commands == ' ')
 			commands++;

 		/* Process any command switches, otherwise skip it. */
 		if (*commands == '\0')
 			break;
 		if (*commands == '-') {
 			commands++;
 			while (*commands && *commands != ' ')
 				process_switch(*commands++);
 			continue;
 		}
 		if (!strncmp(commands, "mem=", 4)) {
 			/*
 			 * "mem=XXX[kKmM] overrides the PROM-reported
 			 * memory size.
 			 */
 			cmdline_memory_size = simple_strtoul(commands + 4,
 						     &commands, 0);
 			if (*commands == 'K' || *commands == 'k') {
 				cmdline_memory_size <<= 10;
 				commands++;
 			} else if (*commands=='M' || *commands=='m') {
 				cmdline_memory_size <<= 20;
 				commands++;
 			}
 		}
 		while (*commands && *commands != ' ')
 			commands++;
 	}
 }

 /* This routine will in the future do all the nasty prom stuff
  * to probe for the mmu type and its parameters, etc. This will
  * also be where SMP things happen plus the Sparc specific memory
  * physical memory probe as on the alpha.
  */

 extern int prom_probe_memory(void);
 extern void sun4c_probe_vac(void);
 extern char cputypval;
 extern unsigned long start, end;
 extern void panic_setup(char *, int *);

 extern unsigned short root_flags;
 extern unsigned short root_dev;
 extern unsigned short ram_flags;
 #define RAMDISK_IMAGE_START_MASK	0x07FF
 #define RAMDISK_PROMPT_FLAG		0x8000
 #define RAMDISK_LOAD_FLAG		0x4000

 extern int root_mountflags;

 char reboot_command[COMMAND_LINE_SIZE];
 enum sparc_cpu sparc_cpu_model;

 struct tt_entry *sparc_ttable;

 struct pt_regs fake_swapper_regs;

 void __init setup_arch(char **cmdline_p)
 {
 	int i;
 	unsigned long highest_paddr;

 	sparc_ttable = (struct tt_entry *) &start;

 	/* Initialize PROM console and command line. */
 	*cmdline_p = prom_getbootargs();
 	strcpy(boot_command_line, *cmdline_p);

 	/* Set sparc_cpu_model */
 	sparc_cpu_model = sun_unknown;
 	if(!strcmp(&cputypval,"sun4 ")) { sparc_cpu_model=sun4; }
 	if(!strcmp(&cputypval,"sun4c")) { sparc_cpu_model=sun4c; }
 	if(!strcmp(&cputypval,"sun4m")) { sparc_cpu_model=sun4m; }
 	if(!strcmp(&cputypval,"sun4s")) { sparc_cpu_model=sun4m; }  /* CP-1200 with PROM 2.30 -E */
 	if(!strcmp(&cputypval,"sun4d")) { sparc_cpu_model=sun4d; }
 	if(!strcmp(&cputypval,"sun4e")) { sparc_cpu_model=sun4e; }
 	if(!strcmp(&cputypval,"sun4u")) { sparc_cpu_model=sun4u; }

 #ifdef CONFIG_SUN4
 	if (sparc_cpu_model != sun4) {
 		prom_printf("This kernel is for Sun4 architecture only.\n");
 		prom_halt();
 	}
 #endif
 	printk("ARCH: ");
 	switch(sparc_cpu_model) {
 	case sun4:
 		printk("SUN4\n");
 		break;
 	case sun4c:
 		printk("SUN4C\n");
 		break;
 	case sun4m:
 		printk("SUN4M\n");
 		break;
 	case sun4d:
 		printk("SUN4D\n");
 		break;
 	case sun4e:
 		printk("SUN4E\n");
 		break;
 	case sun4u:
 		printk("SUN4U\n");
 		break;
 	default:
 		printk("UNKNOWN!\n");
 		break;
 	};

 #ifdef CONFIG_DUMMY_CONSOLE
 	conswitchp = &dummy_con;
 #elif defined(CONFIG_PROM_CONSOLE)
 	conswitchp = &prom_con;
 #endif
 	boot_flags_init(*cmdline_p);

 	idprom_init();
 	if (ARCH_SUN4C_SUN4)
 		sun4c_probe_vac();
 	load_mmu();
 	(void) prom_probe_memory();

 	phys_base = 0xffffffffUL;
 	highest_paddr = 0UL;
 	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
 		unsigned long top;

 		if (sp_banks[i].base_addr < phys_base)
 			phys_base = sp_banks[i].base_addr;
 		top = sp_banks[i].base_addr +
 			sp_banks[i].num_bytes;
 		if (highest_paddr < top)
 			highest_paddr = top;
 	}
 	pfn_base = phys_base >> PAGE_SHIFT;

 	if (!root_flags)
 		root_mountflags &= ~MS_RDONLY;
 	ROOT_DEV = old_decode_dev(root_dev);
 #ifdef CONFIG_BLK_DEV_RAM
 	rd_image_start = ram_flags & RAMDISK_IMAGE_START_MASK;
 	rd_prompt = ((ram_flags & RAMDISK_PROMPT_FLAG) != 0);
 	rd_doload = ((ram_flags & RAMDISK_LOAD_FLAG) != 0);
 #endif

 	prom_setsync(prom_sync_me);

 	if((boot_flags&BOOTME_DEBUG) && (linux_dbvec!=0) &&
 	   ((*(short *)linux_dbvec) != -1)) {
 		printk("Booted under KADB. Syncing trap table.\n");
 		(*(linux_dbvec->teach_debugger))();
 	}

 	init_mm.context = (unsigned long) NO_CONTEXT;
 	init_task.thread.kregs = &fake_swapper_regs;

 	paging_init();

 	smp_setup_cpu_possible_map();
 }

 extern char *sparc_cpu_type;
 extern char *sparc_fpu_type;

 static int ncpus_probed;

 static int show_cpuinfo(struct seq_file *m, void *__unused)
 {
 	seq_printf(m,
 		   "cpu\t\t: %s\n"
 		   "fpu\t\t: %s\n"
 		   "promlib\t\t: Version %d Revision %d\n"
 		   "prom\t\t: %d.%d\n"
 		   "type\t\t: %s\n"
 		   "ncpus probed\t: %d\n"
 		   "ncpus active\t: %d\n"
 #ifndef CONFIG_SMP
 		   "CPU0Bogo\t: %lu.%02lu\n"
 		   "CPU0ClkTck\t: %ld\n"
 #endif
 		   ,
 		   sparc_cpu_type ? sparc_cpu_type : "undetermined",
 		   sparc_fpu_type ? sparc_fpu_type : "undetermined",
 		   romvec->pv_romvers,
 		   prom_rev,
 		   romvec->pv_printrev >> 16,
 		   romvec->pv_printrev & 0xffff,
 		   &cputypval,
 		   ncpus_probed,
 		   num_online_cpus()
 #ifndef CONFIG_SMP
 		   , cpu_data(0).udelay_val/(500000/HZ),
 		   (cpu_data(0).udelay_val/(5000/HZ)) % 100,
 		   cpu_data(0).clock_tick
 #endif
 		);

 #ifdef CONFIG_SMP
 	smp_bogo(m);
 #endif
 	mmu_info(m);
 #ifdef CONFIG_SMP
 	smp_info(m);
 #endif
 	return 0;
 }

 static void *c_start(struct seq_file *m, loff_t *pos)
 {
 	/* The pointer we are returning is arbitrary,
 	 * it just has to be non-NULL and not IS_ERR
 	 * in the success case.
 	 */
 	return *pos == 0 ? &c_start : NULL;
 }

 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	++*pos;
 	return c_start(m, pos);
 }

 static void c_stop(struct seq_file *m, void *v)
 {
 }

 const struct seq_operations cpuinfo_op = {
 	.start =c_start,
 	.next =	c_next,
 	.stop =	c_stop,
 	.show =	show_cpuinfo,
 };

 extern int stop_a_enabled;

 void sun_do_break(void)
 {
 	if (!stop_a_enabled)
 		return;

 	printk("\n");
 	flush_user_windows();

 	prom_cmdline();
 }

 int stop_a_enabled = 1;

 static int __init topology_init(void)
 {
 	int i, ncpus, err;

 	/* Count the number of physically present processors in
 	 * the machine, even on uniprocessor, so that /proc/cpuinfo
 	 * output is consistent with 2.4.x
 	 */
 	ncpus = 0;
 	while (!cpu_find_by_instance(ncpus, NULL, NULL))
 		ncpus++;
 	ncpus_probed = ncpus;

 	err = 0;
 	for_each_online_cpu(i) {
 		struct cpu *p = kzalloc(sizeof(*p), GFP_KERNEL);
 		if (!p)
 			err = -ENOMEM;
 		else
 			register_cpu(p, i);
 	}

 	return err;
 }

 subsys_initcall(topology_init);
	/* $Id: setup.c,v 1.126 2001/11/13 00:49:27 davem Exp $
	* linux/arch/sparc/kernel/setup.c
	*
	* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
	* Copyright (C) 2000 Anton Blanchard (anton@samba.org)
	*/

	#include <linux/errno.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/stddef.h>
	#include <linux/unistd.h>
	#include <linux/ptrace.h>
	#include <linux/slab.h>
	#include <linux/initrd.h>
	#include <asm/smp.h>
	#include <linux/user.h>
	#include <linux/a.out.h>
	#include <linux/screen_info.h>
	#include <linux/delay.h>
	#include <linux/fs.h>
	#include <linux/seq_file.h>
	#include <linux/syscalls.h>
	#include <linux/kdev_t.h>
	#include <linux/major.h>
	#include <linux/string.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/console.h>
	#include <linux/spinlock.h>
	#include <linux/root_dev.h>
	#include <linux/cpu.h>
	#include <linux/kdebug.h>

	#include <asm/system.h>
	#include <asm/io.h>
	#include <asm/processor.h>
	#include <asm/oplib.h>
	#include <asm/page.h>
	#include <asm/pgtable.h>
	#include <asm/traps.h>
	#include <asm/vaddrs.h>
	#include <asm/mbus.h>
	#include <asm/idprom.h>
	#include <asm/machines.h>
	#include <asm/cpudata.h>
	#include <asm/setup.h>

	struct screen_info screen_info = {
	0, 0, /* orig-x, orig-y */
	0, /* unused */
	0, /* orig-video-page */
	0, /* orig-video-mode */
	128, /* orig-video-cols */
	0,0,0, /* ega_ax, ega_bx, ega_cx */
	54, /* orig-video-lines */
	0, /* orig-video-isVGA */
	16 /* orig-video-points */
	};

	/* Typing sync at the prom prompt calls the function pointed to by
	* romvec->pv_synchook which I set to the following function.
	* This should sync all filesystems and return, for now it just
	* prints out pretty messages and returns.
	*/

	extern unsigned long trapbase;
	void (*prom_palette)(int);

	/* Pretty sick eh? */
	void prom_sync_me(void)
	{
	unsigned long prom_tbr, flags;

	/* XXX Badly broken. FIX! - Anton */
	local_irq_save(flags);
	__asm__ __volatile__("rd %%tbr, %0\n\t" : "=r" (prom_tbr));
	__asm__ __volatile__("wr %0, 0x0, %%tbr\n\t"
	"nop\n\t"
	"nop\n\t"
	"nop\n\t" : : "r" (&trapbase));

	if (prom_palette)
	prom_palette(1);
	prom_printf("PROM SYNC COMMAND...\n");
	show_free_areas();
	if(current->pid != 0) {
	local_irq_enable();
	sys_sync();
	local_irq_disable();
	}
	prom_printf("Returning to prom\n");

	__asm__ __volatile__("wr %0, 0x0, %%tbr\n\t"
	"nop\n\t"
	"nop\n\t"
	"nop\n\t" : : "r" (prom_tbr));
	local_irq_restore(flags);

	return;
	}

	unsigned int boot_flags __initdata = 0;
	#define BOOTME_DEBUG 0x1

	/* Exported for mm/init.c:paging_init. */
	unsigned long cmdline_memory_size __initdata = 0;

	static void
	prom_console_write(struct console con, const char s, unsigned n)
	{
	prom_write(s, n);
	}

	static struct console prom_debug_console = {
	.name = "debug",
	.write = prom_console_write,
	.flags = CON_PRINTBUFFER,
	.index = -1,
	};

	/*
	* Process kernel command line switches that are specific to the
	* SPARC or that require special low-level processing.
	*/
	static void __init process_switch(char c)
	{
	switch (c) {
	case 'd':
	boot_flags \|= BOOTME_DEBUG;
	break;
	case 's':
	break;
	case 'h':
	prom_printf("boot_flags_init: Halt!\n");
	prom_halt();
	break;
	case 'p':
	/* Use PROM debug console. */
	register_console(&prom_debug_console);
	break;
	default:
	printk("Unknown boot switch (-%c)\n", c);
	break;
	}
	}

	static void __init boot_flags_init(char *commands)
	{
	while (*commands) {
	/* Move to the start of the next "argument". */
	while (commands && commands == ' ')
	commands++;

	/* Process any command switches, otherwise skip it. */
	if (*commands == '\0')
	break;
	if (*commands == '-') {
	commands++;
	while (commands && commands != ' ')
	process_switch(*commands++);
	continue;
	}
	if (!strncmp(commands, "mem=", 4)) {
	/*
	* "mem=XXX[kKmM] overrides the PROM-reported
	* memory size.
	*/
	cmdline_memory_size = simple_strtoul(commands + 4,
	&commands, 0);
	if (commands == 'K' \|\| commands == 'k') {
	cmdline_memory_size <<= 10;
	commands++;
	} else if (commands=='M' \|\| commands=='m') {
	cmdline_memory_size <<= 20;
	commands++;
	}
	}
	while (commands && commands != ' ')
	commands++;
	}
	}

	/* This routine will in the future do all the nasty prom stuff
	* to probe for the mmu type and its parameters, etc. This will
	* also be where SMP things happen plus the Sparc specific memory
	* physical memory probe as on the alpha.
	*/

	extern int prom_probe_memory(void);
	extern void sun4c_probe_vac(void);
	extern char cputypval;
	extern unsigned long start, end;
	extern void panic_setup(char , int );

	extern unsigned short root_flags;
	extern unsigned short root_dev;
	extern unsigned short ram_flags;
	#define RAMDISK_IMAGE_START_MASK 0x07FF
	#define RAMDISK_PROMPT_FLAG 0x8000
	#define RAMDISK_LOAD_FLAG 0x4000

	extern int root_mountflags;

	char reboot_command[COMMAND_LINE_SIZE];
	enum sparc_cpu sparc_cpu_model;

	struct tt_entry *sparc_ttable;

	struct pt_regs fake_swapper_regs;

	void __init setup_arch(char **cmdline_p)
	{
	int i;
	unsigned long highest_paddr;

	sparc_ttable = (struct tt_entry *) &start;

	/* Initialize PROM console and command line. */
	*cmdline_p = prom_getbootargs();
	strcpy(boot_command_line, *cmdline_p);

	/* Set sparc_cpu_model */
	sparc_cpu_model = sun_unknown;
	if(!strcmp(&cputypval,"sun4 ")) { sparc_cpu_model=sun4; }
	if(!strcmp(&cputypval,"sun4c")) { sparc_cpu_model=sun4c; }
	if(!strcmp(&cputypval,"sun4m")) { sparc_cpu_model=sun4m; }
	if(!strcmp(&cputypval,"sun4s")) { sparc_cpu_model=sun4m; } /* CP-1200 with PROM 2.30 -E */
	if(!strcmp(&cputypval,"sun4d")) { sparc_cpu_model=sun4d; }
	if(!strcmp(&cputypval,"sun4e")) { sparc_cpu_model=sun4e; }
	if(!strcmp(&cputypval,"sun4u")) { sparc_cpu_model=sun4u; }

	#ifdef CONFIG_SUN4
	if (sparc_cpu_model != sun4) {
	prom_printf("This kernel is for Sun4 architecture only.\n");
	prom_halt();
	}
	#endif
	printk("ARCH: ");
	switch(sparc_cpu_model) {
	case sun4:
	printk("SUN4\n");
	break;
	case sun4c:
	printk("SUN4C\n");
	break;
	case sun4m:
	printk("SUN4M\n");
	break;
	case sun4d:
	printk("SUN4D\n");
	break;
	case sun4e:
	printk("SUN4E\n");
	break;
	case sun4u:
	printk("SUN4U\n");
	break;
	default:
	printk("UNKNOWN!\n");
	break;
	};

	#ifdef CONFIG_DUMMY_CONSOLE
	conswitchp = &dummy_con;
	#elif defined(CONFIG_PROM_CONSOLE)
	conswitchp = &prom_con;
	#endif
	boot_flags_init(*cmdline_p);

	idprom_init();
	if (ARCH_SUN4C_SUN4)
	sun4c_probe_vac();
	load_mmu();
	(void) prom_probe_memory();

	phys_base = 0xffffffffUL;
	highest_paddr = 0UL;
	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
	unsigned long top;

	if (sp_banks[i].base_addr < phys_base)
	phys_base = sp_banks[i].base_addr;
	top = sp_banks[i].base_addr +
	sp_banks[i].num_bytes;
	if (highest_paddr < top)
	highest_paddr = top;
	}
	pfn_base = phys_base >> PAGE_SHIFT;

	if (!root_flags)
	root_mountflags &= ~MS_RDONLY;
	ROOT_DEV = old_decode_dev(root_dev);
	#ifdef CONFIG_BLK_DEV_RAM
	rd_image_start = ram_flags & RAMDISK_IMAGE_START_MASK;
	rd_prompt = ((ram_flags & RAMDISK_PROMPT_FLAG) != 0);
	rd_doload = ((ram_flags & RAMDISK_LOAD_FLAG) != 0);
	#endif

	prom_setsync(prom_sync_me);

	if((boot_flags&BOOTME_DEBUG) && (linux_dbvec!=0) &&
	(((short )linux_dbvec) != -1)) {
	printk("Booted under KADB. Syncing trap table.\n");
	(*(linux_dbvec->teach_debugger))();
	}

	init_mm.context = (unsigned long) NO_CONTEXT;
	init_task.thread.kregs = &fake_swapper_regs;

	paging_init();

	smp_setup_cpu_possible_map();
	}

	extern char *sparc_cpu_type;
	extern char *sparc_fpu_type;

	static int ncpus_probed;

	static int show_cpuinfo(struct seq_file m, void __unused)
	{
	seq_printf(m,
	"cpu\t\t: %s\n"
	"fpu\t\t: %s\n"
	"promlib\t\t: Version %d Revision %d\n"
	"prom\t\t: %d.%d\n"
	"type\t\t: %s\n"
	"ncpus probed\t: %d\n"
	"ncpus active\t: %d\n"
	#ifndef CONFIG_SMP
	"CPU0Bogo\t: %lu.%02lu\n"
	"CPU0ClkTck\t: %ld\n"
	#endif
	,
	sparc_cpu_type ? sparc_cpu_type : "undetermined",
	sparc_fpu_type ? sparc_fpu_type : "undetermined",
	romvec->pv_romvers,
	prom_rev,
	romvec->pv_printrev >> 16,
	romvec->pv_printrev & 0xffff,
	&cputypval,
	ncpus_probed,
	num_online_cpus()
	#ifndef CONFIG_SMP
	, cpu_data(0).udelay_val/(500000/HZ),
	(cpu_data(0).udelay_val/(5000/HZ)) % 100,
	cpu_data(0).clock_tick
	#endif
	);

	#ifdef CONFIG_SMP
	smp_bogo(m);
	#endif
	mmu_info(m);
	#ifdef CONFIG_SMP
	smp_info(m);
	#endif
	return 0;
	}

	static void c_start(struct seq_file m, loff_t *pos)
	{
	/* The pointer we are returning is arbitrary,
	* it just has to be non-NULL and not IS_ERR
	* in the success case.
	*/
	return *pos == 0 ? &c_start : NULL;
	}

	static void c_next(struct seq_file m, void v, loff_t pos)
	{
	++*pos;
	return c_start(m, pos);
	}

	static void c_stop(struct seq_file m, void v)
	{
	}

	const struct seq_operations cpuinfo_op = {
	.start =c_start,
	.next = c_next,
	.stop = c_stop,
	.show = show_cpuinfo,
	};

	extern int stop_a_enabled;

	void sun_do_break(void)
	{
	if (!stop_a_enabled)
	return;

	printk("\n");
	flush_user_windows();

	prom_cmdline();
	}

	int stop_a_enabled = 1;

	static int __init topology_init(void)
	{
	int i, ncpus, err;

	/* Count the number of physically present processors in
	* the machine, even on uniprocessor, so that /proc/cpuinfo
	* output is consistent with 2.4.x
	*/
	ncpus = 0;
	while (!cpu_find_by_instance(ncpus, NULL, NULL))
	ncpus++;
	ncpus_probed = ncpus;

	err = 0;
	for_each_online_cpu(i) {
	struct cpu p = kzalloc(sizeof(p), GFP_KERNEL);
	if (!p)
	err = -ENOMEM;
	else
	register_cpu(p, i);
	}

	return err;
	}

	subsys_initcall(topology_init);