* 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)
+ * Stem compression by Andi Kleen.
*/
#include <linux/kallsyms.h>
#include <linux/module.h>
/* 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));
-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));
+extern char kallsyms_names[] __attribute__((weak));
/* Defined by the linker script. */
extern char _stext[], _etext[], _sinittext[], _einittext[];
return 0;
}
-/* 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;
+ char *knames;
- for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
- off = kallsyms_expand_symbol(off, namebuf);
+ for (i = 0, knames = kallsyms_names; i < kallsyms_num_syms; i++) {
+ unsigned prefix = *knames++;
+ strlcpy(namebuf + prefix, knames, KSYM_NAME_LEN - prefix);
if (strcmp(namebuf, name) == 0)
return kallsyms_addresses[i];
+
+ knames += strlen(knames) + 1;
}
return module_kallsyms_lookup_name(name);
}
unsigned long *offset,
char **modname, char *namebuf)
{
- unsigned long i, low, high, mid;
+ unsigned long i, best = 0;
/* This kernel should never had been booted. */
BUG_ON(!kallsyms_addresses);
namebuf[0] = 0;
if (is_kernel_text(addr) || is_kernel_inittext(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;
+ unsigned long symbol_end;
+ char *name = kallsyms_names;
+
+ /* They're sorted, we could be clever here, but who cares? */
+ for (i = 0; i < kallsyms_num_syms; i++) {
+ if (kallsyms_addresses[i] > kallsyms_addresses[best] &&
+ kallsyms_addresses[i] <= addr)
+ best = i;
}
- /* 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);
+ for (i = 0; i <= best; i++) {
+ unsigned prefix = *name++;
+ strncpy(namebuf + prefix, name, KSYM_NAME_LEN - prefix);
+ name += strlen(name) + 1;
+ }
+
+ /* At worst, symbol ends at end of section. */
+ if (is_kernel_inittext(addr))
+ symbol_end = (unsigned long)_einittext;
+ else
+ symbol_end = (unsigned long)_etext;
/* Search for next non-aliased symbol */
- for (i = low + 1; i < kallsyms_num_syms; i++) {
- if (kallsyms_addresses[i] > kallsyms_addresses[low]) {
+ for (i = best+1; i < kallsyms_num_syms; i++) {
+ if (kallsyms_addresses[i] > kallsyms_addresses[best]) {
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 = (unsigned long)_etext;
- }
-
- *symbolsize = symbol_end - kallsyms_addresses[low];
+ *symbolsize = symbol_end - kallsyms_addresses[best];
*modname = NULL;
- *offset = addr - kallsyms_addresses[low];
+ *offset = addr - kallsyms_addresses[best];
return namebuf;
}
printk(fmt, buffer);
}
-/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
+/* To avoid O(n^2) iteration, we carry prefix along. */
struct kallsym_iter
{
loff_t pos;
/* Returns space to next name. */
static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
{
- unsigned off = iter->nameoff;
+ unsigned stemlen, off = iter->nameoff;
+
+ /* First char of each symbol name indicates prefix length
+ shared with previous name (stem compression). */
+ stemlen = kallsyms_names[off++];
+ strlcpy(iter->name+stemlen, kallsyms_names + off,
+ KSYM_NAME_LEN+1-stemlen);
+ off += strlen(kallsyms_names + off) + 1;
iter->owner = NULL;
iter->value = kallsyms_addresses[iter->pos];
+ if (is_kernel_text(iter->value) || is_kernel_inittext(iter->value))
+ iter->type = 't';
+ else
+ iter->type = 'd';
- iter->type = kallsyms_get_symbol_type(off);
-
- off = kallsyms_expand_symbol(off, iter->name);
-
+ upcase_if_global(iter);
return off - iter->nameoff;
}
-static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
+static void reset_iter(struct kallsym_iter *iter)
{
iter->name[0] = '\0';
- iter->nameoff = get_symbol_offset(new_pos);
- iter->pos = new_pos;
+ iter->nameoff = 0;
+ iter->pos = 0;
}
/* Returns false if pos at or past end of file. */
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++;
-
+ /* If we're past the desired position, reset to start. */
+ if (pos < iter->pos)
+ reset_iter(iter);
+
+ /* We need to iterate through the previous symbols: can be slow */
+ for (; iter->pos != pos; iter->pos++) {
+ iter->nameoff += get_ksymbol_core(iter);
+ cond_resched();
+ }
+ get_ksymbol_core(iter);
return 1;
}
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 */
+ * s_start from where we left off, so we avoid O(N^2). */
struct kallsym_iter *iter;
int ret;
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
- reset_iter(iter, 0);
+ reset_iter(iter);
ret = seq_open(file, &kallsyms_op);
if (ret == 0)
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