[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);
}

/* 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);
}

/*
 * 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)
{
	unsigned long i, low, high, mid;
	const char *msym;

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

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

	if ((all_var && is_kernel(addr)) ||
	    (!all_var && (is_kernel_text(addr) || is_kernel_inittext(addr) ||
				is_kernel_extratext(addr)))) {
		unsigned long symbol_end = 0;

		/* 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;

		/* Grab name */
		kallsyms_expand_symbol(get_symbol_offset(low), namebuf);

		/* Search for next non-aliased symbol */
		for (i = low + 1; i < kallsyms_num_syms; i++) {
			if (kallsyms_addresses[i] > kallsyms_addresses[low]) {
				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
				symbol_end = all_var ? (unsigned long)_end : (unsigned long)_etext;
		}

		*symbolsize = symbol_end - kallsyms_addresses[low];
		*modname = NULL;
		*offset = addr - kallsyms_addresses[low];
		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
	72	/* expand a compressed symbol data into the resulting uncompressed string,
	73	given the offset to where the symbol is in the compressed stream */
	74	static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
	75	{
	76	int len, skipped_first = 0;
	77	u8 tptr, data;
	78
	79	/* get the compressed symbol length from the first symbol byte */
	80	data = &kallsyms_names[off];
	81	len = *data;
	82	data++;
	83
	84	/* update the offset to return the offset for the next symbol on
	85	* the compressed stream */
	86	off += len + 1;
	87
	88	/* for every byte on the compressed symbol data, copy the table
	89	entry for that byte */
	90	while(len) {
	91	tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
	92	data++;
	93	len--;
	94
	95	while (*tptr) {
	96	if(skipped_first) {
	97	result = tptr;
	98	result++;
	99	} else
	100	skipped_first = 1;
	101	tptr++;
	102	}
	103	}
	104
	105	*result = '\0';
	106
	107	/* return to offset to the next symbol */
	108	return off;
	109	}
	110
	111	/* get symbol type information. This is encoded as a single char at the
	112	* begining of the symbol name */
	113	static char kallsyms_get_symbol_type(unsigned int off)
	114	{
	115	/* get just the first code, look it up in the token table, and return the
	116	* first char from this token */
	117	return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
	118	}
	119
	120
	121	/* find the offset on the compressed stream given and index in the
122	* kallsyms array */
123	static unsigned int get_symbol_offset(unsigned long pos)
124	{
125	u8 *name;
126	int i;
127
128	/* use the closest marker we have. We have markers every 256 positions,
129	* so that should be close enough */
130	name = &kallsyms_names[ kallsyms_markers[pos>>8] ];
131
132	/* sequentially scan all the symbols up to the point we're searching for.
133	* Every symbol is stored in a [<len>][<len> bytes of data] format, so we
134	* just need to add the len to the current pointer for every symbol we
135	* wish to skip */
136	for(i = 0; i < (pos&0xFF); i++)
137	name = name + (*name) + 1;
138
139	return name - kallsyms_names;
140	}
141
142	/* Lookup the address for this symbol. Returns 0 if not found. */
143	unsigned long kallsyms_lookup_name(const char *name)
144	{
145	char namebuf[KSYM_NAME_LEN+1];
146	unsigned long i;
147	unsigned int off;
148
149	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
150	off = kallsyms_expand_symbol(off, namebuf);
151
152	if (strcmp(namebuf, name) == 0)
153	return kallsyms_addresses[i];
154	}
155	return module_kallsyms_lookup_name(name);
156	}
1da177e4 LT	157
	158	/*
	159	* Lookup an address
	160	* - modname is set to NULL if it's in the kernel
	161	* - we guarantee that the returned name is valid until we reschedule even if
	162	* it resides in a module
	163	* - we also guarantee that modname will be valid until rescheduled
	164	*/
	165	const char *kallsyms_lookup(unsigned long addr,
	166	unsigned long *symbolsize,
	167	unsigned long *offset,
	168	char *modname, char namebuf)
	169	{
	170	unsigned long i, low, high, mid;
	171	const char *msym;
	172
	173	/* This kernel should never had been booted. */
	174	BUG_ON(!kallsyms_addresses);
	175
	176	namebuf[KSYM_NAME_LEN] = 0;
	177	namebuf[0] = 0;
	178
	179	if ((all_var && is_kernel(addr)) \|\|
075d6eb1 DW	180	(!all_var && (is_kernel_text(addr) \|\| is_kernel_inittext(addr) \|\|
	181	is_kernel_extratext(addr)))) {
	182	unsigned long symbol_end = 0;
1da177e4 LT	183
	184	/* do a binary search on the sorted kallsyms_addresses array */
	185	low = 0;
	186	high = kallsyms_num_syms;
	187
	188	while (high-low > 1) {
	189	mid = (low + high) / 2;
	190	if (kallsyms_addresses[mid] <= addr) low = mid;
	191	else high = mid;
	192	}
	193
	194	/* search for the first aliased symbol. Aliased symbols are
	195	symbols with the same address */
	196	while (low && kallsyms_addresses[low - 1] == kallsyms_addresses[low])
	197	--low;
	198
	199	/* Grab name */
	200	kallsyms_expand_symbol(get_symbol_offset(low), namebuf);
	201
	202	/* Search for next non-aliased symbol */
	203	for (i = low + 1; i < kallsyms_num_syms; i++) {
	204	if (kallsyms_addresses[i] > kallsyms_addresses[low]) {
	205	symbol_end = kallsyms_addresses[i];
	206	break;
	207	}
	208	}
	209
	210	/* if we found no next symbol, we use the end of the section */
	211	if (!symbol_end) {
	212	if (is_kernel_inittext(addr))
	213	symbol_end = (unsigned long)_einittext;
	214	else
	215	symbol_end = all_var ? (unsigned long)_end : (unsigned long)_etext;
	216	}
	217
	218	*symbolsize = symbol_end - kallsyms_addresses[low];
	219	*modname = NULL;
	220	*offset = addr - kallsyms_addresses[low];
	221	return namebuf;
	222	}
	223
	224	/* see if it's in a module */
	225	msym = module_address_lookup(addr, symbolsize, offset, modname);
	226	if (msym)
	227	return strncpy(namebuf, msym, KSYM_NAME_LEN);
	228
	229	return NULL;
	230	}
	231
	232	/* Replace "%s" in format with address, or returns -errno. */
	233	void __print_symbol(const char *fmt, unsigned long address)
	234	{
	235	char *modname;
	236	const char *name;
	237	unsigned long offset, size;
	238	char namebuf[KSYM_NAME_LEN+1];
	239	char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
	240	2(BITS_PER_LONG3/10) + MODULE_NAME_LEN + 1];
	241
	242	name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
	243
	244	if (!name)
	245	sprintf(buffer, "0x%lx", address);
	246	else {
247	if (modname)
248	sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
249	size, modname);
250	else
251	sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
252	}
253	printk(fmt, buffer);
254	}
255
256	/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
257	struct kallsym_iter
258	{
259	loff_t pos;
260	struct module *owner;
261	unsigned long value;
262	unsigned int nameoff; /* If iterating in core kernel symbols */
263	char type;
264	char name[KSYM_NAME_LEN+1];
265	};
266
267	/* Only label it "global" if it is exported. */
268	static void upcase_if_global(struct kallsym_iter *iter)
269	{
270	if (is_exported(iter->name, iter->owner))
271	iter->type += 'A' - 'a';
272	}
273
274	static int get_ksymbol_mod(struct kallsym_iter *iter)
275	{
276	iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
098c5eea AG	277	&iter->value, &iter->type,
098c5eea AG	278	iter->name, sizeof(iter->name));
1da177e4 LT	279	if (iter->owner == NULL)
	280	return 0;
	281
	282	upcase_if_global(iter);
	283	return 1;
	284	}
	285
	286	/* Returns space to next name. */
	287	static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
	288	{
	289	unsigned off = iter->nameoff;
	290
	291	iter->owner = NULL;
	292	iter->value = kallsyms_addresses[iter->pos];
	293
	294	iter->type = kallsyms_get_symbol_type(off);
	295
	296	off = kallsyms_expand_symbol(off, iter->name);
	297
	298	return off - iter->nameoff;
	299	}
	300
	301	static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
	302	{
	303	iter->name[0] = '\0';
	304	iter->nameoff = get_symbol_offset(new_pos);
	305	iter->pos = new_pos;
	306	}
	307
	308	/* Returns false if pos at or past end of file. */
	309	static int update_iter(struct kallsym_iter *iter, loff_t pos)
	310	{
	311	/* Module symbols can be accessed randomly. */
	312	if (pos >= kallsyms_num_syms) {
	313	iter->pos = pos;
	314	return get_ksymbol_mod(iter);
	315	}
	316
	317	/* If we're not on the desired position, reset to new position. */
	318	if (pos != iter->pos)
	319	reset_iter(iter, pos);
	320
	321	iter->nameoff += get_ksymbol_core(iter);
	322	iter->pos++;
	323
	324	return 1;
	325	}
	326
	327	static void s_next(struct seq_file m, void p, loff_t pos)
	328	{
	329	(*pos)++;
	330
	331	if (!update_iter(m->private, *pos))
	332	return NULL;
	333	return p;
	334	}
	335
	336	static void s_start(struct seq_file m, loff_t *pos)
	337	{
	338	if (!update_iter(m->private, *pos))
	339	return NULL;
	340	return m->private;
	341	}
	342
343	static void s_stop(struct seq_file m, void p)
344	{
345	}
346
347	static int s_show(struct seq_file m, void p)
348	{
349	struct kallsym_iter *iter = m->private;
350
351	/* Some debugging symbols have no name. Ignore them. */
352	if (!iter->name[0])
353	return 0;
354
355	if (iter->owner)
356	seq_printf(m, "%0*lx %c %s\t[%s]\n",
357	(int)(2sizeof(void)),
358	iter->value, iter->type, iter->name,
359	module_name(iter->owner));
360	else
361	seq_printf(m, "%0*lx %c %s\n",
362	(int)(2sizeof(void)),
363	iter->value, iter->type, iter->name);
364	return 0;
365	}
366
367	static struct seq_operations kallsyms_op = {
368	.start = s_start,
369	.next = s_next,
370	.stop = s_stop,
371	.show = s_show
372	};
373
374	static int kallsyms_open(struct inode inode, struct file file)
375	{
376	/* We keep iterator in m->private, since normal case is to
377	* s_start from where we left off, so we avoid doing
378	* using get_symbol_offset for every symbol */
379	struct kallsym_iter *iter;
380	int ret;
381
382	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
383	if (!iter)
384	return -ENOMEM;
385	reset_iter(iter, 0);
386
387	ret = seq_open(file, &kallsyms_op);
388	if (ret == 0)
389	((struct seq_file *)file->private_data)->private = iter;
390	else
391	kfree(iter);
392	return ret;
393	}
394
395	static int kallsyms_release(struct inode inode, struct file file)
396	{
397	struct seq_file m = (struct seq_file )file->private_data;
398	kfree(m->private);
399	return seq_release(inode, file);
400	}
401
402	static struct file_operations kallsyms_operations = {
403	.open = kallsyms_open,
404	.read = seq_read,
405	.llseek = seq_lseek,
406	.release = kallsyms_release,
407	};
408
409	static int __init kallsyms_init(void)
410	{
411	struct proc_dir_entry *entry;
412
413	entry = create_proc_entry("kallsyms", 0444, NULL);
414	if (entry)
415	entry->proc_fops = &kallsyms_operations;
416	return 0;
417	}
418	__initcall(kallsyms_init);
419
420	EXPORT_SYMBOL(__print_symbol);