* Rewritten and vastly simplified by Rusty Russell for in-kernel
* module loader:
* Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
- * Stem compression by Andi Kleen.
+ *
+ * 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/fs.h>
#include <linux/err.h>
#include <linux/proc_fs.h>
+#include <linux/sched.h> /* for cond_resched */
+#include <linux/mm.h>
+#include <linux/ctype.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));
-extern char kallsyms_names[] __attribute__((weak));
+extern const unsigned long kallsyms_addresses[] __attribute__((weak));
+extern const unsigned long kallsyms_num_syms __attribute__((weak));
+extern const u8 kallsyms_names[] __attribute__((weak));
+
+extern const u8 kallsyms_token_table[] __attribute__((weak));
+extern const u16 kallsyms_token_index[] __attribute__((weak));
-/* Defined by the linker script. */
-extern char _stext[], _etext[], _sinittext[], _einittext[];
+extern const unsigned long kallsyms_markers[] __attribute__((weak));
static inline int is_kernel_inittext(unsigned long addr)
{
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 0;
+ 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;
+ const 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)
+{
+ const 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. */
{
char namebuf[KSYM_NAME_LEN+1];
unsigned long i;
- char *knames;
+ unsigned int off;
- for (i = 0, knames = kallsyms_names; i < kallsyms_num_syms; i++) {
- unsigned prefix = *knames++;
+ for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
+ off = kallsyms_expand_symbol(off, namebuf);
- 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);
}
-/* Lookup an address. modname is set to NULL if it's in the kernel. */
-const char *kallsyms_lookup(unsigned long addr,
- unsigned long *symbolsize,
- unsigned long *offset,
- char **modname, char *namebuf)
+static unsigned long get_symbol_pos(unsigned long addr,
+ unsigned long *symbolsize,
+ unsigned long *offset)
{
- unsigned long i, best = 0;
+ 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);
- namebuf[KSYM_NAME_LEN] = 0;
- namebuf[0] = 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;
+ }
- if (is_kernel_text(addr) || is_kernel_inittext(addr)) {
- unsigned long symbol_end;
- char *name = kallsyms_names;
+ /*
+ * search for the first aliased symbol. Aliased
+ * symbols are symbols with the same address
+ */
+ while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
+ --low;
- /* 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;
- }
+ symbol_start = kallsyms_addresses[low];
- /* Grab name */
- for (i = 0; i <= best; i++) {
- unsigned prefix = *name++;
- strncpy(namebuf + prefix, name, KSYM_NAME_LEN - prefix);
- name += strlen(name) + 1;
+ /* 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;
}
+ }
- /* At worst, symbol ends at end of section. */
+ /* 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;
+ }
- /* Search for next non-aliased symbol */
- for (i = best+1; i < kallsyms_num_syms; i++) {
- if (kallsyms_addresses[i] > kallsyms_addresses[best]) {
- symbol_end = kallsyms_addresses[i];
- break;
- }
- }
+ *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;
- *symbolsize = symbol_end - kallsyms_addresses[best];
+ 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;
- *offset = addr - kallsyms_addresses[best];
return namebuf;
}
- return module_address_lookup(addr, symbolsize, offset, modname);
+ /* 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. */
printk(fmt, buffer);
}
-/* To avoid O(n^2) iteration, we carry prefix along. */
+/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
struct kallsym_iter
{
loff_t pos;
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);
+ &iter->value, &iter->type,
+ iter->name, sizeof(iter->name));
if (iter->owner == NULL)
return 0;
- upcase_if_global(iter);
+ /* Label it "global" if it is exported, "local" if not exported. */
+ iter->type = is_exported(iter->name, iter->owner)
+ ? toupper(iter->type) : tolower(iter->type);
+
return 1;
}
/* Returns space to next name. */
static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
{
- unsigned stemlen, off = iter->nameoff;
+ unsigned 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';
- upcase_if_global(iter);
+ 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)
+static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
{
iter->name[0] = '\0';
- iter->nameoff = 0;
- iter->pos = 0;
+ iter->nameoff = get_symbol_offset(new_pos);
+ iter->pos = new_pos;
}
/* Returns false if pos at or past end of file. */
return get_ksymbol_mod(iter);
}
- /* 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);
+ /* 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;
}
return 0;
}
-struct seq_operations kallsyms_op = {
+static const struct seq_operations kallsyms_op = {
.start = s_start,
.next = s_next,
.stop = s_stop,
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 O(N^2). */
+ * 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);
+ reset_iter(iter, 0);
ret = seq_open(file, &kallsyms_op);
if (ret == 0)
return seq_release(inode, file);
}
-static struct file_operations kallsyms_operations = {
+static const struct file_operations kallsyms_operations = {
.open = kallsyms_open,
.read = seq_read,
.llseek = seq_lseek,
.release = kallsyms_release,
};
-int __init kallsyms_init(void)
+static int __init kallsyms_init(void)
{
struct proc_dir_entry *entry;
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