634 lines
16 KiB
C
634 lines
16 KiB
C
/*
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* kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
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*
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* Rewritten and vastly simplified by Rusty Russell for in-kernel
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* module loader:
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* Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
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*
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* ChangeLog:
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*
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* (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
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* Changed the compression method from stem compression to "table lookup"
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* compression (see scripts/kallsyms.c for a more complete description)
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*/
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#include <linux/kallsyms.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/seq_file.h>
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#include <linux/fs.h>
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#include <linux/kdb.h>
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#include <linux/err.h>
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#include <linux/proc_fs.h>
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#include <linux/sched.h> /* for cond_resched */
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#include <linux/mm.h>
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#include <linux/ctype.h>
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#include <linux/slab.h>
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#include <linux/compiler.h>
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#include <asm/sections.h>
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#ifdef CONFIG_SEC_DEBUG_SUMMARY
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#include <linux/qcom/sec_debug.h>
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#include <linux/qcom/sec_debug_summary.h>
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#endif
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#ifdef CONFIG_KALLSYMS_ALL
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#define all_var 1
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#else
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#define all_var 0
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#endif
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/*
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* These will be re-linked against their real values
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* during the second link stage.
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*/
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extern const unsigned long kallsyms_addresses[] __weak;
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extern const u8 kallsyms_names[] __weak;
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/*
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* Tell the compiler that the count isn't in the small data section if the arch
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* has one (eg: FRV).
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*/
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extern const unsigned long kallsyms_num_syms
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__attribute__((weak, section(".rodata")));
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extern const u8 kallsyms_token_table[] __weak;
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extern const u16 kallsyms_token_index[] __weak;
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extern const unsigned long kallsyms_markers[] __weak;
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#ifdef CONFIG_SEC_DEBUG_SUMMARY
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void sec_debug_summary_set_kallsyms_info(struct sec_debug_summary_data_apss *apss)
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{
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apss->ksyms.addresses_pa = __pa(kallsyms_addresses);
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apss->ksyms.names_pa = __pa(kallsyms_names);
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apss->ksyms.num_syms = kallsyms_num_syms;
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apss->ksyms.token_table_pa = __pa(kallsyms_token_table);
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apss->ksyms.token_index_pa = __pa(kallsyms_token_index);
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apss->ksyms.markers_pa = __pa(kallsyms_markers);
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apss->ksyms.sect.sinittext = (uint64_t)_sinittext;
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apss->ksyms.sect.einittext = (uint64_t)_einittext;
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apss->ksyms.sect.stext = (uint64_t)_stext;
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apss->ksyms.sect.etext = (uint64_t)_etext;
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apss->ksyms.sect.end = (uint64_t)_end;
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apss->ksyms.kallsyms_all = all_var;
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apss->ksyms.magic = SEC_DEBUG_SUMMARY_MAGIC1;
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}
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#endif
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static inline int is_kernel_inittext(unsigned long addr)
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{
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if (addr >= (unsigned long)_sinittext
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&& addr <= (unsigned long)_einittext)
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return 1;
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return 0;
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}
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static inline int is_kernel_text(unsigned long addr)
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{
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if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
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arch_is_kernel_text(addr))
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return 1;
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return in_gate_area_no_mm(addr);
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}
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static inline int is_kernel(unsigned long addr)
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{
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if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
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return 1;
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return in_gate_area_no_mm(addr);
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}
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static int is_ksym_addr(unsigned long addr)
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{
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if (all_var)
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return is_kernel(addr);
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return is_kernel_text(addr) || is_kernel_inittext(addr);
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}
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/*
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* Expand a compressed symbol data into the resulting uncompressed string,
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* if uncompressed string is too long (>= maxlen), it will be truncated,
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* given the offset to where the symbol is in the compressed stream.
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*/
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static unsigned int kallsyms_expand_symbol(unsigned int off,
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char *result, size_t maxlen)
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{
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int len, skipped_first = 0;
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const u8 *tptr, *data;
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/* Get the compressed symbol length from the first symbol byte. */
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data = &kallsyms_names[off];
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len = *data;
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data++;
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/*
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* Update the offset to return the offset for the next symbol on
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* the compressed stream.
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*/
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off += len + 1;
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/*
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* For every byte on the compressed symbol data, copy the table
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* entry for that byte.
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*/
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while (len) {
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tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
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data++;
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len--;
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while (*tptr) {
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if (skipped_first) {
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if (maxlen <= 1)
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goto tail;
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*result = *tptr;
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result++;
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maxlen--;
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} else
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skipped_first = 1;
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tptr++;
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}
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}
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tail:
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if (maxlen)
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*result = '\0';
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/* Return to offset to the next symbol. */
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return off;
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}
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/*
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* Get symbol type information. This is encoded as a single char at the
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* beginning of the symbol name.
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*/
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static char kallsyms_get_symbol_type(unsigned int off)
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{
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/*
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* Get just the first code, look it up in the token table,
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* and return the first char from this token.
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*/
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return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
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}
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/*
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* Find the offset on the compressed stream given and index in the
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* kallsyms array.
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*/
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static unsigned int get_symbol_offset(unsigned long pos)
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{
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const u8 *name;
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int i;
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/*
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* Use the closest marker we have. We have markers every 256 positions,
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* so that should be close enough.
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*/
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name = &kallsyms_names[kallsyms_markers[pos >> 8]];
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/*
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* Sequentially scan all the symbols up to the point we're searching
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* for. Every symbol is stored in a [<len>][<len> bytes of data] format,
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* so we just need to add the len to the current pointer for every
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* symbol we wish to skip.
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*/
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for (i = 0; i < (pos & 0xFF); i++)
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name = name + (*name) + 1;
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return name - kallsyms_names;
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}
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/* Lookup the address for this symbol. Returns 0 if not found. */
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unsigned long kallsyms_lookup_name(const char *name)
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{
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char namebuf[KSYM_NAME_LEN];
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unsigned long i;
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unsigned int off;
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for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
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off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
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if (strcmp(namebuf, name) == 0)
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return kallsyms_addresses[i];
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}
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return module_kallsyms_lookup_name(name);
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}
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EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
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int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
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unsigned long),
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void *data)
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{
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char namebuf[KSYM_NAME_LEN];
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unsigned long i;
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unsigned int off;
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int ret;
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for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
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off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
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ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
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if (ret != 0)
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return ret;
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}
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return module_kallsyms_on_each_symbol(fn, data);
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}
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EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
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static unsigned long get_symbol_pos(unsigned long addr,
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unsigned long *symbolsize,
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unsigned long *offset)
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{
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unsigned long symbol_start = 0, symbol_end = 0;
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unsigned long i, low, high, mid;
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/* This kernel should never had been booted. */
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BUG_ON(!kallsyms_addresses);
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/* Do a binary search on the sorted kallsyms_addresses array. */
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low = 0;
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high = kallsyms_num_syms;
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while (high - low > 1) {
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mid = low + (high - low) / 2;
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if (kallsyms_addresses[mid] <= addr)
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low = mid;
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else
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high = mid;
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}
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/*
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* Search for the first aliased symbol. Aliased
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* symbols are symbols with the same address.
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*/
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while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
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--low;
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symbol_start = kallsyms_addresses[low];
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/* Search for next non-aliased symbol. */
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for (i = low + 1; i < kallsyms_num_syms; i++) {
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if (kallsyms_addresses[i] > symbol_start) {
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symbol_end = kallsyms_addresses[i];
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break;
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}
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}
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/* If we found no next symbol, we use the end of the section. */
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if (!symbol_end) {
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if (is_kernel_inittext(addr))
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symbol_end = (unsigned long)_einittext;
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else if (all_var)
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symbol_end = (unsigned long)_end;
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else
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symbol_end = (unsigned long)_etext;
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}
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if (symbolsize)
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*symbolsize = symbol_end - symbol_start;
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if (offset)
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*offset = addr - symbol_start;
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return low;
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}
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/*
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* Lookup an address but don't bother to find any names.
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*/
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int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
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unsigned long *offset)
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{
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char namebuf[KSYM_NAME_LEN];
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if (is_ksym_addr(addr))
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return !!get_symbol_pos(addr, symbolsize, offset);
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return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf);
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}
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/*
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* Lookup an address
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* - modname is set to NULL if it's in the kernel.
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* - We guarantee that the returned name is valid until we reschedule even if.
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* It resides in a module.
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* - We also guarantee that modname will be valid until rescheduled.
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*/
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const char *kallsyms_lookup(unsigned long addr,
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unsigned long *symbolsize,
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unsigned long *offset,
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char **modname, char *namebuf)
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{
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namebuf[KSYM_NAME_LEN - 1] = 0;
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namebuf[0] = 0;
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if (is_ksym_addr(addr)) {
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unsigned long pos;
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pos = get_symbol_pos(addr, symbolsize, offset);
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/* Grab name */
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kallsyms_expand_symbol(get_symbol_offset(pos),
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namebuf, KSYM_NAME_LEN);
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if (modname)
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*modname = NULL;
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return namebuf;
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}
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/* See if it's in a module. */
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return module_address_lookup(addr, symbolsize, offset, modname,
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namebuf);
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}
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int lookup_symbol_name(unsigned long addr, char *symname)
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{
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symname[0] = '\0';
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symname[KSYM_NAME_LEN - 1] = '\0';
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if (is_ksym_addr(addr)) {
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unsigned long pos;
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pos = get_symbol_pos(addr, NULL, NULL);
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/* Grab name */
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kallsyms_expand_symbol(get_symbol_offset(pos),
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symname, KSYM_NAME_LEN);
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return 0;
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}
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/* See if it's in a module. */
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return lookup_module_symbol_name(addr, symname);
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}
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int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
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unsigned long *offset, char *modname, char *name)
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{
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name[0] = '\0';
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name[KSYM_NAME_LEN - 1] = '\0';
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if (is_ksym_addr(addr)) {
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unsigned long pos;
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pos = get_symbol_pos(addr, size, offset);
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/* Grab name */
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kallsyms_expand_symbol(get_symbol_offset(pos),
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name, KSYM_NAME_LEN);
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modname[0] = '\0';
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return 0;
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}
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/* See if it's in a module. */
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return lookup_module_symbol_attrs(addr, size, offset, modname, name);
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}
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/* Look up a kernel symbol and return it in a text buffer. */
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static int __sprint_symbol(char *buffer, unsigned long address,
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int symbol_offset, int add_offset)
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{
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char *modname;
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const char *name;
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unsigned long offset, size;
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int len;
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address += symbol_offset;
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name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
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if (!name)
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return sprintf(buffer, "0x%lx", address - symbol_offset);
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if (name != buffer)
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strcpy(buffer, name);
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len = strlen(buffer);
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offset -= symbol_offset;
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if (add_offset)
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len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
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if (modname)
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len += sprintf(buffer + len, " [%s]", modname);
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return len;
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}
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/**
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* sprint_symbol - Look up a kernel symbol and return it in a text buffer
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* @buffer: buffer to be stored
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* @address: address to lookup
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*
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* This function looks up a kernel symbol with @address and stores its name,
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* offset, size and module name to @buffer if possible. If no symbol was found,
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* just saves its @address as is.
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*
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* This function returns the number of bytes stored in @buffer.
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*/
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int sprint_symbol(char *buffer, unsigned long address)
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{
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return __sprint_symbol(buffer, address, 0, 1);
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}
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EXPORT_SYMBOL_GPL(sprint_symbol);
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/**
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* sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
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* @buffer: buffer to be stored
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* @address: address to lookup
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*
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* This function looks up a kernel symbol with @address and stores its name
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* and module name to @buffer if possible. If no symbol was found, just saves
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* its @address as is.
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*
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* This function returns the number of bytes stored in @buffer.
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*/
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int sprint_symbol_no_offset(char *buffer, unsigned long address)
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{
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return __sprint_symbol(buffer, address, 0, 0);
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}
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EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
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/**
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* sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
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* @buffer: buffer to be stored
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* @address: address to lookup
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*
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* This function is for stack backtrace and does the same thing as
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* sprint_symbol() but with modified/decreased @address. If there is a
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* tail-call to the function marked "noreturn", gcc optimized out code after
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* the call so that the stack-saved return address could point outside of the
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* caller. This function ensures that kallsyms will find the original caller
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* by decreasing @address.
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*
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* This function returns the number of bytes stored in @buffer.
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*/
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int sprint_backtrace(char *buffer, unsigned long address)
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{
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return __sprint_symbol(buffer, address, -1, 1);
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}
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/* Look up a kernel symbol and print it to the kernel messages. */
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void __print_symbol(const char *fmt, unsigned long address)
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{
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char buffer[KSYM_SYMBOL_LEN];
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sprint_symbol(buffer, address);
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printk(fmt, buffer);
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}
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EXPORT_SYMBOL(__print_symbol);
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/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
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struct kallsym_iter {
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loff_t pos;
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unsigned long value;
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unsigned int nameoff; /* If iterating in core kernel symbols. */
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char type;
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char name[KSYM_NAME_LEN];
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char module_name[MODULE_NAME_LEN];
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int exported;
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};
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static int get_ksymbol_mod(struct kallsym_iter *iter)
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{
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if (module_get_kallsym(iter->pos - kallsyms_num_syms, &iter->value,
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&iter->type, iter->name, iter->module_name,
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&iter->exported) < 0)
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return 0;
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return 1;
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}
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/* Returns space to next name. */
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static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
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{
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unsigned off = iter->nameoff;
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iter->module_name[0] = '\0';
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iter->value = kallsyms_addresses[iter->pos];
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iter->type = kallsyms_get_symbol_type(off);
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off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));
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return off - iter->nameoff;
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}
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static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
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{
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iter->name[0] = '\0';
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iter->nameoff = get_symbol_offset(new_pos);
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iter->pos = new_pos;
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}
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/* Returns false if pos at or past end of file. */
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static int update_iter(struct kallsym_iter *iter, loff_t pos)
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{
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/* Module symbols can be accessed randomly. */
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if (pos >= kallsyms_num_syms) {
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iter->pos = pos;
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return get_ksymbol_mod(iter);
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}
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/* If we're not on the desired position, reset to new position. */
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if (pos != iter->pos)
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reset_iter(iter, pos);
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iter->nameoff += get_ksymbol_core(iter);
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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->module_name[0]) {
|
|
char type;
|
|
|
|
/*
|
|
* Label it "global" if it is exported,
|
|
* "local" if not exported.
|
|
*/
|
|
type = iter->exported ? toupper(iter->type) :
|
|
tolower(iter->type);
|
|
seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value,
|
|
type, iter->name, iter->module_name);
|
|
} else
|
|
seq_printf(m, "%pK %c %s\n", (void *)iter->value,
|
|
iter->type, iter->name);
|
|
return 0;
|
|
}
|
|
|
|
static const 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;
|
|
iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
reset_iter(iter, 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_KGDB_KDB
|
|
const char *kdb_walk_kallsyms(loff_t *pos)
|
|
{
|
|
static struct kallsym_iter kdb_walk_kallsyms_iter;
|
|
if (*pos == 0) {
|
|
memset(&kdb_walk_kallsyms_iter, 0,
|
|
sizeof(kdb_walk_kallsyms_iter));
|
|
reset_iter(&kdb_walk_kallsyms_iter, 0);
|
|
}
|
|
while (1) {
|
|
if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
|
|
return NULL;
|
|
++*pos;
|
|
/* Some debugging symbols have no name. Ignore them. */
|
|
if (kdb_walk_kallsyms_iter.name[0])
|
|
return kdb_walk_kallsyms_iter.name;
|
|
}
|
|
}
|
|
#endif /* CONFIG_KGDB_KDB */
|
|
|
|
static const struct file_operations kallsyms_operations = {
|
|
.open = kallsyms_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release_private,
|
|
};
|
|
|
|
static int __init kallsyms_init(void)
|
|
{
|
|
proc_create("kallsyms", 0444, NULL, &kallsyms_operations);
|
|
return 0;
|
|
}
|
|
device_initcall(kallsyms_init);
|