|  | /* | 
|  | * 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); | 
|  | } | 
|  | EXPORT_SYMBOL_GPL(kallsyms_lookup_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); | 
|  | 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); |