[linux-block.git] / kernel / kallsyms.c

/*
 * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
 *
 * Rewritten and vastly simplified by Rusty Russell for in-kernel
 * module loader:
 *   Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
 *
 * ChangeLog:
 *
 * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
 *      Changed the compression method from stem compression to "table lookup"
 *      compression (see scripts/kallsyms.c for a more complete description)
 */
#include <linux/kallsyms.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>	/* for cond_resched */
#include <linux/mm.h>

#include <asm/sections.h>

#ifdef CONFIG_KALLSYMS_ALL
#define all_var 1
#else
#define all_var 0
#endif

/* These will be re-linked against their real values during the second link stage */
extern unsigned long kallsyms_addresses[] __attribute__((weak));
extern unsigned long kallsyms_num_syms __attribute__((weak,section("data")));
extern u8 kallsyms_names[] __attribute__((weak));

extern u8 kallsyms_token_table[] __attribute__((weak));
extern u16 kallsyms_token_index[] __attribute__((weak));

extern unsigned long kallsyms_markers[] __attribute__((weak));

static inline int is_kernel_inittext(unsigned long addr)
{
	if (addr >= (unsigned long)_sinittext
	    && addr <= (unsigned long)_einittext)
		return 1;
	return 0;
}

static inline int is_kernel_extratext(unsigned long addr)
{
	if (addr >= (unsigned long)_sextratext
	    && addr <= (unsigned long)_eextratext)
		return 1;
	return 0;
}

static inline int is_kernel_text(unsigned long addr)
{
	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
		return 1;
	return in_gate_area_no_task(addr);
}

static inline int is_kernel(unsigned long addr)
{
	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
		return 1;
	return in_gate_area_no_task(addr);
}

static int is_ksym_addr(unsigned long addr)
{
	if (all_var)
		return is_kernel(addr);

	return is_kernel_text(addr) || is_kernel_inittext(addr) ||
		is_kernel_extratext(addr);
}

/* expand a compressed symbol data into the resulting uncompressed string,
   given the offset to where the symbol is in the compressed stream */
static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
{
	int len, skipped_first = 0;
	u8 *tptr, *data;

	/* get the compressed symbol length from the first symbol byte */
	data = &kallsyms_names[off];
	len = *data;
	data++;

	/* update the offset to return the offset for the next symbol on
	 * the compressed stream */
	off += len + 1;

	/* for every byte on the compressed symbol data, copy the table
	   entry for that byte */
	while(len) {
		tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
		data++;
		len--;

		while (*tptr) {
			if(skipped_first) {
				*result = *tptr;
				result++;
			} else
				skipped_first = 1;
			tptr++;
		}
	}

	*result = '\0';

	/* return to offset to the next symbol */
	return off;
}

/* get symbol type information. This is encoded as a single char at the
 * begining of the symbol name */
static char kallsyms_get_symbol_type(unsigned int off)
{
	/* get just the first code, look it up in the token table, and return the
	 * first char from this token */
	return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
}


/* find the offset on the compressed stream given and index in the
 * kallsyms array */
static unsigned int get_symbol_offset(unsigned long pos)
{
	u8 *name;
	int i;

	/* use the closest marker we have. We have markers every 256 positions,
	 * so that should be close enough */
	name = &kallsyms_names[ kallsyms_markers[pos>>8] ];

	/* sequentially scan all the symbols up to the point we're searching for.
	 * Every symbol is stored in a [<len>][<len> bytes of data] format, so we
	 * just need to add the len to the current pointer for every symbol we
	 * wish to skip */
	for(i = 0; i < (pos&0xFF); i++)
		name = name + (*name) + 1;

	return name - kallsyms_names;
}

/* Lookup the address for this symbol. Returns 0 if not found. */
unsigned long kallsyms_lookup_name(const char *name)
{
	char namebuf[KSYM_NAME_LEN+1];
	unsigned long i;
	unsigned int off;

	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
		off = kallsyms_expand_symbol(off, namebuf);

		if (strcmp(namebuf, name) == 0)
			return kallsyms_addresses[i];
	}
	return module_kallsyms_lookup_name(name);
}

static unsigned long get_symbol_pos(unsigned long addr,
				    unsigned long *symbolsize,
				    unsigned long *offset)
{
	unsigned long symbol_start = 0, symbol_end = 0;
	unsigned long i, low, high, mid;

	/* This kernel should never had been booted. */
	BUG_ON(!kallsyms_addresses);

	/* do a binary search on the sorted kallsyms_addresses array */
	low = 0;
	high = kallsyms_num_syms;

	while (high - low > 1) {
		mid = (low + high) / 2;
		if (kallsyms_addresses[mid] <= addr)
			low = mid;
		else
			high = mid;
	}

	/*
	 * search for the first aliased symbol. Aliased
	 * symbols are symbols with the same address
	 */
	while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
		--low;

	symbol_start = kallsyms_addresses[low];

	/* Search for next non-aliased symbol */
	for (i = low + 1; i < kallsyms_num_syms; i++) {
		if (kallsyms_addresses[i] > symbol_start) {
			symbol_end = kallsyms_addresses[i];
			break;
		}
	}

	/* if we found no next symbol, we use the end of the section */
	if (!symbol_end) {
		if (is_kernel_inittext(addr))
			symbol_end = (unsigned long)_einittext;
		else if (all_var)
			symbol_end = (unsigned long)_end;
		else
			symbol_end = (unsigned long)_etext;
	}

	*symbolsize = symbol_end - symbol_start;
	*offset = addr - symbol_start;

	return low;
}

/*
 * Lookup an address but don't bother to find any names.
 */
int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
				unsigned long *offset)
{
	if (is_ksym_addr(addr))
		return !!get_symbol_pos(addr, symbolsize, offset);

	return !!module_address_lookup(addr, symbolsize, offset, NULL);
}

/*
 * Lookup an address
 * - modname is set to NULL if it's in the kernel
 * - we guarantee that the returned name is valid until we reschedule even if
 *   it resides in a module
 * - we also guarantee that modname will be valid until rescheduled
 */
const char *kallsyms_lookup(unsigned long addr,
			    unsigned long *symbolsize,
			    unsigned long *offset,
			    char **modname, char *namebuf)
{
	const char *msym;

	namebuf[KSYM_NAME_LEN] = 0;
	namebuf[0] = 0;

	if (is_ksym_addr(addr)) {
		unsigned long pos;

		pos = get_symbol_pos(addr, symbolsize, offset);
		/* Grab name */
		kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
		*modname = NULL;
		return namebuf;
	}

	/* see if it's in a module */
	msym = module_address_lookup(addr, symbolsize, offset, modname);
	if (msym)
		return strncpy(namebuf, msym, KSYM_NAME_LEN);

	return NULL;
}

/* Replace "%s" in format with address, or returns -errno. */
void __print_symbol(const char *fmt, unsigned long address)
{
	char *modname;
	const char *name;
	unsigned long offset, size;
	char namebuf[KSYM_NAME_LEN+1];
	char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
		    2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1];

	name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);

	if (!name)
		sprintf(buffer, "0x%lx", address);
	else {
		if (modname)
			sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
				size, modname);
		else
			sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
	}
	printk(fmt, buffer);
}

/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
struct kallsym_iter
{
	loff_t pos;
	struct module *owner;
	unsigned long value;
	unsigned int nameoff; /* If iterating in core kernel symbols */
	char type;
	char name[KSYM_NAME_LEN+1];
};

/* Only label it "global" if it is exported. */
static void upcase_if_global(struct kallsym_iter *iter)
{
	if (is_exported(iter->name, iter->owner))
		iter->type += 'A' - 'a';
}

static int get_ksymbol_mod(struct kallsym_iter *iter)
{
	iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
					 &iter->value, &iter->type,
					 iter->name, sizeof(iter->name));
	if (iter->owner == NULL)
		return 0;

	upcase_if_global(iter);
	return 1;
}

/* Returns space to next name. */
static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
{
	unsigned off = iter->nameoff;

	iter->owner = NULL;
	iter->value = kallsyms_addresses[iter->pos];

	iter->type = kallsyms_get_symbol_type(off);

	off = kallsyms_expand_symbol(off, iter->name);

	return off - iter->nameoff;
}

static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
{
	iter->name[0] = '\0';
	iter->nameoff = get_symbol_offset(new_pos);
	iter->pos = new_pos;
}

/* Returns false if pos at or past end of file. */
static int update_iter(struct kallsym_iter *iter, loff_t pos)
{
	/* Module symbols can be accessed randomly. */
	if (pos >= kallsyms_num_syms) {
		iter->pos = pos;
		return get_ksymbol_mod(iter);
	}
	
	/* If we're not on the desired position, reset to new position. */
	if (pos != iter->pos)
		reset_iter(iter, pos);

	iter->nameoff += get_ksymbol_core(iter);
	iter->pos++;

	return 1;
}

static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
	(*pos)++;

	if (!update_iter(m->private, *pos))
		return NULL;
	return p;
}

static void *s_start(struct seq_file *m, loff_t *pos)
{
	if (!update_iter(m->private, *pos))
		return NULL;
	return m->private;
}

static void s_stop(struct seq_file *m, void *p)
{
}

static int s_show(struct seq_file *m, void *p)
{
	struct kallsym_iter *iter = m->private;

	/* Some debugging symbols have no name.  Ignore them. */ 
	if (!iter->name[0])
		return 0;

	if (iter->owner)
		seq_printf(m, "%0*lx %c %s\t[%s]\n",
			   (int)(2*sizeof(void*)),
			   iter->value, iter->type, iter->name,
			   module_name(iter->owner));
	else
		seq_printf(m, "%0*lx %c %s\n",
			   (int)(2*sizeof(void*)),
			   iter->value, iter->type, iter->name);
	return 0;
}

static struct seq_operations kallsyms_op = {
	.start = s_start,
	.next = s_next,
	.stop = s_stop,
	.show = s_show
};

static int kallsyms_open(struct inode *inode, struct file *file)
{
	/* We keep iterator in m->private, since normal case is to
	 * s_start from where we left off, so we avoid doing
	 * using get_symbol_offset for every symbol */
	struct kallsym_iter *iter;
	int ret;

	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
	if (!iter)
		return -ENOMEM;
	reset_iter(iter, 0);

	ret = seq_open(file, &kallsyms_op);
	if (ret == 0)
		((struct seq_file *)file->private_data)->private = iter;
	else
		kfree(iter);
	return ret;
}

static int kallsyms_release(struct inode *inode, struct file *file)
{
	struct seq_file *m = (struct seq_file *)file->private_data;
	kfree(m->private);
	return seq_release(inode, file);
}

static struct file_operations kallsyms_operations = {
	.open = kallsyms_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = kallsyms_release,
};

static int __init kallsyms_init(void)
{
	struct proc_dir_entry *entry;

	entry = create_proc_entry("kallsyms", 0444, NULL);
	if (entry)
		entry->proc_fops = &kallsyms_operations;
	return 0;
}
__initcall(kallsyms_init);

EXPORT_SYMBOL(__print_symbol);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
	3	*
	4	* Rewritten and vastly simplified by Rusty Russell for in-kernel
	5	* module loader:
	6	* Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
	7	*
	8	* ChangeLog:
	9	*
	10	* (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
	11	* Changed the compression method from stem compression to "table lookup"
	12	* compression (see scripts/kallsyms.c for a more complete description)
	13	*/
	14	#include <linux/kallsyms.h>
	15	#include <linux/module.h>
	16	#include <linux/init.h>
	17	#include <linux/seq_file.h>
	18	#include <linux/fs.h>
	19	#include <linux/err.h>
	20	#include <linux/proc_fs.h>
4e57b681	21	#include <linux/sched.h> /* for cond_resched */
1da177e4 LT	22	#include <linux/mm.h>
	23
	24	#include <asm/sections.h>
	25
	26	#ifdef CONFIG_KALLSYMS_ALL
	27	#define all_var 1
	28	#else
	29	#define all_var 0
	30	#endif
	31
	32	/* These will be re-linked against their real values during the second link stage */
	33	extern unsigned long kallsyms_addresses[] __attribute__((weak));
	34	extern unsigned long kallsyms_num_syms __attribute__((weak,section("data")));
	35	extern u8 kallsyms_names[] __attribute__((weak));
	36
	37	extern u8 kallsyms_token_table[] __attribute__((weak));
	38	extern u16 kallsyms_token_index[] __attribute__((weak));
	39
	40	extern unsigned long kallsyms_markers[] __attribute__((weak));
	41
	42	static inline int is_kernel_inittext(unsigned long addr)
	43	{
	44	if (addr >= (unsigned long)_sinittext
	45	&& addr <= (unsigned long)_einittext)
	46	return 1;
	47	return 0;
	48	}
	49
075d6eb1 DW	50	static inline int is_kernel_extratext(unsigned long addr)
	51	{
	52	if (addr >= (unsigned long)_sextratext
	53	&& addr <= (unsigned long)_eextratext)
	54	return 1;
	55	return 0;
	56	}
	57
1da177e4 LT	58	static inline int is_kernel_text(unsigned long addr)
	59	{
	60	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
	61	return 1;
	62	return in_gate_area_no_task(addr);
	63	}
	64
	65	static inline int is_kernel(unsigned long addr)
	66	{
	67	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
	68	return 1;
	69	return in_gate_area_no_task(addr);
	70	}
	71
ffc50891 FBH	72	static int is_ksym_addr(unsigned long addr)
	73	{
	74	if (all_var)
	75	return is_kernel(addr);
	76
	77	return is_kernel_text(addr) \|\| is_kernel_inittext(addr) \|\|
	78	is_kernel_extratext(addr);
	79	}
	80
1da177e4 LT	81	/* expand a compressed symbol data into the resulting uncompressed string,
	82	given the offset to where the symbol is in the compressed stream */
	83	static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
	84	{
	85	int len, skipped_first = 0;
	86	u8 tptr, data;
	87
	88	/* get the compressed symbol length from the first symbol byte */
	89	data = &kallsyms_names[off];
	90	len = *data;
	91	data++;
	92
	93	/* update the offset to return the offset for the next symbol on
	94	* the compressed stream */
	95	off += len + 1;
	96
	97	/* for every byte on the compressed symbol data, copy the table
	98	entry for that byte */
	99	while(len) {
	100	tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
	101	data++;
	102	len--;
	103
	104	while (*tptr) {
	105	if(skipped_first) {
	106	result = tptr;
	107	result++;
	108	} else
	109	skipped_first = 1;
	110	tptr++;
	111	}
	112	}
	113
	114	*result = '\0';
	115
	116	/* return to offset to the next symbol */
	117	return off;
	118	}
	119
	120	/* get symbol type information. This is encoded as a single char at the
	121	* begining of the symbol name */
	122	static char kallsyms_get_symbol_type(unsigned int off)
	123	{
	124	/* get just the first code, look it up in the token table, and return the
	125	* first char from this token */
	126	return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
	127	}
	128
	129
	130	/* find the offset on the compressed stream given and index in the
	131	* kallsyms array */
	132	static unsigned int get_symbol_offset(unsigned long pos)
	133	{
	134	u8 *name;
	135	int i;
	136
	137	/* use the closest marker we have. We have markers every 256 positions,
	138	* so that should be close enough */
	139	name = &kallsyms_names[ kallsyms_markers[pos>>8] ];
	140
	141	/* sequentially scan all the symbols up to the point we're searching for.
	142	* Every symbol is stored in a [<len>][<len> bytes of data] format, so we
	143	* just need to add the len to the current pointer for every symbol we
	144	* wish to skip */
145	for(i = 0; i < (pos&0xFF); i++)
146	name = name + (*name) + 1;
147
148	return name - kallsyms_names;
149	}
150
151	/* Lookup the address for this symbol. Returns 0 if not found. */
152	unsigned long kallsyms_lookup_name(const char *name)
153	{
154	char namebuf[KSYM_NAME_LEN+1];
155	unsigned long i;
156	unsigned int off;
157
158	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
159	off = kallsyms_expand_symbol(off, namebuf);
160
161	if (strcmp(namebuf, name) == 0)
162	return kallsyms_addresses[i];
163	}
164	return module_kallsyms_lookup_name(name);
165	}
1da177e4	166
ffc50891 FBH	167	static unsigned long get_symbol_pos(unsigned long addr,
	168	unsigned long *symbolsize,
	169	unsigned long *offset)
	170	{
	171	unsigned long symbol_start = 0, symbol_end = 0;
	172	unsigned long i, low, high, mid;
	173
	174	/* This kernel should never had been booted. */
	175	BUG_ON(!kallsyms_addresses);
	176
	177	/* do a binary search on the sorted kallsyms_addresses array */
	178	low = 0;
	179	high = kallsyms_num_syms;
	180
	181	while (high - low > 1) {
	182	mid = (low + high) / 2;
	183	if (kallsyms_addresses[mid] <= addr)
	184	low = mid;
	185	else
	186	high = mid;
	187	}
	188
	189	/*
	190	* search for the first aliased symbol. Aliased
	191	* symbols are symbols with the same address
	192	*/
	193	while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
	194	--low;
	195
	196	symbol_start = kallsyms_addresses[low];
	197
	198	/* Search for next non-aliased symbol */
	199	for (i = low + 1; i < kallsyms_num_syms; i++) {
	200	if (kallsyms_addresses[i] > symbol_start) {
	201	symbol_end = kallsyms_addresses[i];
	202	break;
	203	}
	204	}
	205
	206	/* if we found no next symbol, we use the end of the section */
	207	if (!symbol_end) {
	208	if (is_kernel_inittext(addr))
	209	symbol_end = (unsigned long)_einittext;
	210	else if (all_var)
	211	symbol_end = (unsigned long)_end;
	212	else
	213	symbol_end = (unsigned long)_etext;
	214	}
	215
	216	*symbolsize = symbol_end - symbol_start;
	217	*offset = addr - symbol_start;
	218
	219	return low;
	220	}
	221
	222	/*
	223	* Lookup an address but don't bother to find any names.
	224	*/
	225	int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
	226	unsigned long *offset)
	227	{
	228	if (is_ksym_addr(addr))
	229	return !!get_symbol_pos(addr, symbolsize, offset);
	230
231	return !!module_address_lookup(addr, symbolsize, offset, NULL);
232	}
233
1da177e4 LT	234	/*
	235	* Lookup an address
	236	* - modname is set to NULL if it's in the kernel
	237	* - we guarantee that the returned name is valid until we reschedule even if
	238	* it resides in a module
	239	* - we also guarantee that modname will be valid until rescheduled
	240	*/
	241	const char *kallsyms_lookup(unsigned long addr,
	242	unsigned long *symbolsize,
	243	unsigned long *offset,
	244	char *modname, char namebuf)
	245	{
1da177e4 LT	246	const char *msym;
1da177e4 LT	247
1da177e4 LT	248	namebuf[KSYM_NAME_LEN] = 0;
	249	namebuf[0] = 0;
	250
ffc50891 FBH	251	if (is_ksym_addr(addr)) {
ffc50891 FBH	252	unsigned long pos;
1da177e4	253
ffc50891	254	pos = get_symbol_pos(addr, symbolsize, offset);
1da177e4	255	/* Grab name */
ffc50891	256	kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
1da177e4	257	*modname = NULL;
1da177e4 LT	258	return namebuf;
	259	}
	260
	261	/* see if it's in a module */
	262	msym = module_address_lookup(addr, symbolsize, offset, modname);
	263	if (msym)
	264	return strncpy(namebuf, msym, KSYM_NAME_LEN);
	265
	266	return NULL;
	267	}
	268
	269	/* Replace "%s" in format with address, or returns -errno. */
	270	void __print_symbol(const char *fmt, unsigned long address)
	271	{
	272	char *modname;
	273	const char *name;
	274	unsigned long offset, size;
	275	char namebuf[KSYM_NAME_LEN+1];
	276	char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
	277	2(BITS_PER_LONG3/10) + MODULE_NAME_LEN + 1];
	278
	279	name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
	280
	281	if (!name)
	282	sprintf(buffer, "0x%lx", address);
	283	else {
	284	if (modname)
	285	sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
	286	size, modname);
	287	else
	288	sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
	289	}
	290	printk(fmt, buffer);
	291	}
	292
	293	/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
	294	struct kallsym_iter
	295	{
	296	loff_t pos;
	297	struct module *owner;
	298	unsigned long value;
	299	unsigned int nameoff; /* If iterating in core kernel symbols */
	300	char type;
	301	char name[KSYM_NAME_LEN+1];
	302	};
	303
	304	/* Only label it "global" if it is exported. */
	305	static void upcase_if_global(struct kallsym_iter *iter)
	306	{
	307	if (is_exported(iter->name, iter->owner))
	308	iter->type += 'A' - 'a';
	309	}
	310
	311	static int get_ksymbol_mod(struct kallsym_iter *iter)
	312	{
	313	iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
098c5eea AG	314	&iter->value, &iter->type,
098c5eea AG	315	iter->name, sizeof(iter->name));
1da177e4 LT	316	if (iter->owner == NULL)
	317	return 0;
	318
	319	upcase_if_global(iter);
	320	return 1;
	321	}
	322
	323	/* Returns space to next name. */
	324	static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
	325	{
	326	unsigned off = iter->nameoff;
	327
	328	iter->owner = NULL;
	329	iter->value = kallsyms_addresses[iter->pos];
	330
	331	iter->type = kallsyms_get_symbol_type(off);
	332
	333	off = kallsyms_expand_symbol(off, iter->name);
	334
	335	return off - iter->nameoff;
	336	}
	337
	338	static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
	339	{
	340	iter->name[0] = '\0';
	341	iter->nameoff = get_symbol_offset(new_pos);
	342	iter->pos = new_pos;
	343	}
	344
	345	/* Returns false if pos at or past end of file. */
	346	static int update_iter(struct kallsym_iter *iter, loff_t pos)
	347	{
	348	/* Module symbols can be accessed randomly. */
	349	if (pos >= kallsyms_num_syms) {
	350	iter->pos = pos;
	351	return get_ksymbol_mod(iter);
	352	}
	353
	354	/* If we're not on the desired position, reset to new position. */
	355	if (pos != iter->pos)
	356	reset_iter(iter, pos);
	357
	358	iter->nameoff += get_ksymbol_core(iter);
	359	iter->pos++;
	360
	361	return 1;
	362	}
	363
	364	static void s_next(struct seq_file m, void p, loff_t pos)
	365	{
	366	(*pos)++;
	367
	368	if (!update_iter(m->private, *pos))
	369	return NULL;
	370	return p;
	371	}
	372
	373	static void s_start(struct seq_file m, loff_t *pos)
	374	{
	375	if (!update_iter(m->private, *pos))
	376	return NULL;
	377	return m->private;
	378	}
	379
380	static void s_stop(struct seq_file m, void p)
381	{
382	}
383
384	static int s_show(struct seq_file m, void p)
385	{
386	struct kallsym_iter *iter = m->private;
387
388	/* Some debugging symbols have no name. Ignore them. */
389	if (!iter->name[0])
390	return 0;
391
392	if (iter->owner)
393	seq_printf(m, "%0*lx %c %s\t[%s]\n",
394	(int)(2sizeof(void)),
395	iter->value, iter->type, iter->name,
396	module_name(iter->owner));
397	else
398	seq_printf(m, "%0*lx %c %s\n",
399	(int)(2sizeof(void)),
400	iter->value, iter->type, iter->name);
401	return 0;
402	}
403
404	static struct seq_operations kallsyms_op = {
405	.start = s_start,
406	.next = s_next,
407	.stop = s_stop,
408	.show = s_show
409	};
410
411	static int kallsyms_open(struct inode inode, struct file file)
412	{
413	/* We keep iterator in m->private, since normal case is to
414	* s_start from where we left off, so we avoid doing
415	* using get_symbol_offset for every symbol */
416	struct kallsym_iter *iter;
417	int ret;
418
419	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
420	if (!iter)
421	return -ENOMEM;
422	reset_iter(iter, 0);
423
424	ret = seq_open(file, &kallsyms_op);
425	if (ret == 0)
426	((struct seq_file *)file->private_data)->private = iter;
427	else
428	kfree(iter);
429	return ret;
430	}
431
432	static int kallsyms_release(struct inode inode, struct file file)
433	{
434	struct seq_file m = (struct seq_file )file->private_data;
435	kfree(m->private);
436	return seq_release(inode, file);
437	}
438
439	static struct file_operations kallsyms_operations = {
440	.open = kallsyms_open,
441	.read = seq_read,
442	.llseek = seq_lseek,
443	.release = kallsyms_release,
444	};
445
446	static int __init kallsyms_init(void)
447	{
448	struct proc_dir_entry *entry;
449
450	entry = create_proc_entry("kallsyms", 0444, NULL);
451	if (entry)
452	entry->proc_fops = &kallsyms_operations;
453	return 0;
454	}
455	__initcall(kallsyms_init);
456
457	EXPORT_SYMBOL(__print_symbol);