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-rw-r--r--scripts/kallsyms.c793
1 files changed, 793 insertions, 0 deletions
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
new file mode 100644
index 000000000..54ad86d13
--- /dev/null
+++ b/scripts/kallsyms.c
@@ -0,0 +1,793 @@
+/* Generate assembler source containing symbol information
+ *
+ * Copyright 2002 by Kai Germaschewski
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ *
+ * Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S
+ *
+ * Table compression uses all the unused char codes on the symbols and
+ * maps these to the most used substrings (tokens). For instance, it might
+ * map char code 0xF7 to represent "write_" and then in every symbol where
+ * "write_" appears it can be replaced by 0xF7, saving 5 bytes.
+ * The used codes themselves are also placed in the table so that the
+ * decompresion can work without "special cases".
+ * Applied to kernel symbols, this usually produces a compression ratio
+ * of about 50%.
+ *
+ */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
+
+#define KSYM_NAME_LEN 128
+
+struct sym_entry {
+ unsigned long long addr;
+ unsigned int len;
+ unsigned int start_pos;
+ unsigned int percpu_absolute;
+ unsigned char sym[];
+};
+
+struct addr_range {
+ const char *start_sym, *end_sym;
+ unsigned long long start, end;
+};
+
+static unsigned long long _text;
+static unsigned long long relative_base;
+static struct addr_range text_ranges[] = {
+ { "_stext", "_etext" },
+ { "_sinittext", "_einittext" },
+};
+#define text_range_text (&text_ranges[0])
+#define text_range_inittext (&text_ranges[1])
+
+static struct addr_range percpu_range = {
+ "__per_cpu_start", "__per_cpu_end", -1ULL, 0
+};
+
+static struct sym_entry **table;
+static unsigned int table_size, table_cnt;
+static int all_symbols;
+static int absolute_percpu;
+static int base_relative;
+
+static int token_profit[0x10000];
+
+/* the table that holds the result of the compression */
+static unsigned char best_table[256][2];
+static unsigned char best_table_len[256];
+
+
+static void usage(void)
+{
+ fprintf(stderr, "Usage: kallsyms [--all-symbols] "
+ "[--base-relative] < in.map > out.S\n");
+ exit(1);
+}
+
+static char *sym_name(const struct sym_entry *s)
+{
+ return (char *)s->sym + 1;
+}
+
+static bool is_ignored_symbol(const char *name, char type)
+{
+ /* Symbol names that exactly match to the following are ignored.*/
+ static const char * const ignored_symbols[] = {
+ /*
+ * Symbols which vary between passes. Passes 1 and 2 must have
+ * identical symbol lists. The kallsyms_* symbols below are
+ * only added after pass 1, they would be included in pass 2
+ * when --all-symbols is specified so exclude them to get a
+ * stable symbol list.
+ */
+ "kallsyms_addresses",
+ "kallsyms_offsets",
+ "kallsyms_relative_base",
+ "kallsyms_num_syms",
+ "kallsyms_names",
+ "kallsyms_markers",
+ "kallsyms_token_table",
+ "kallsyms_token_index",
+ /* Exclude linker generated symbols which vary between passes */
+ "_SDA_BASE_", /* ppc */
+ "_SDA2_BASE_", /* ppc */
+ NULL
+ };
+
+ /* Symbol names that begin with the following are ignored.*/
+ static const char * const ignored_prefixes[] = {
+ "$", /* local symbols for ARM, MIPS, etc. */
+ ".LASANPC", /* s390 kasan local symbols */
+ "__crc_", /* modversions */
+ "__efistub_", /* arm64 EFI stub namespace */
+ "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */
+ "__AArch64ADRPThunk_", /* arm64 lld */
+ "__ARMV5PILongThunk_", /* arm lld */
+ "__ARMV7PILongThunk_",
+ "__ThumbV7PILongThunk_",
+ "__LA25Thunk_", /* mips lld */
+ "__microLA25Thunk_",
+ NULL
+ };
+
+ /* Symbol names that end with the following are ignored.*/
+ static const char * const ignored_suffixes[] = {
+ "_from_arm", /* arm */
+ "_from_thumb", /* arm */
+ "_veneer", /* arm */
+ NULL
+ };
+
+ /* Symbol names that contain the following are ignored.*/
+ static const char * const ignored_matches[] = {
+ ".long_branch.", /* ppc stub */
+ ".plt_branch.", /* ppc stub */
+ NULL
+ };
+
+ const char * const *p;
+
+ for (p = ignored_symbols; *p; p++)
+ if (!strcmp(name, *p))
+ return true;
+
+ for (p = ignored_prefixes; *p; p++)
+ if (!strncmp(name, *p, strlen(*p)))
+ return true;
+
+ for (p = ignored_suffixes; *p; p++) {
+ int l = strlen(name) - strlen(*p);
+
+ if (l >= 0 && !strcmp(name + l, *p))
+ return true;
+ }
+
+ for (p = ignored_matches; *p; p++) {
+ if (strstr(name, *p))
+ return true;
+ }
+
+ if (type == 'U' || type == 'u')
+ return true;
+ /* exclude debugging symbols */
+ if (type == 'N' || type == 'n')
+ return true;
+
+ if (toupper(type) == 'A') {
+ /* Keep these useful absolute symbols */
+ if (strcmp(name, "__kernel_syscall_via_break") &&
+ strcmp(name, "__kernel_syscall_via_epc") &&
+ strcmp(name, "__kernel_sigtramp") &&
+ strcmp(name, "__gp"))
+ return true;
+ }
+
+ return false;
+}
+
+static void check_symbol_range(const char *sym, unsigned long long addr,
+ struct addr_range *ranges, int entries)
+{
+ size_t i;
+ struct addr_range *ar;
+
+ for (i = 0; i < entries; ++i) {
+ ar = &ranges[i];
+
+ if (strcmp(sym, ar->start_sym) == 0) {
+ ar->start = addr;
+ return;
+ } else if (strcmp(sym, ar->end_sym) == 0) {
+ ar->end = addr;
+ return;
+ }
+ }
+}
+
+static struct sym_entry *read_symbol(FILE *in)
+{
+ char name[500], type;
+ unsigned long long addr;
+ unsigned int len;
+ struct sym_entry *sym;
+ int rc;
+
+ rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
+ if (rc != 3) {
+ if (rc != EOF && fgets(name, 500, in) == NULL)
+ fprintf(stderr, "Read error or end of file.\n");
+ return NULL;
+ }
+ if (strlen(name) >= KSYM_NAME_LEN) {
+ fprintf(stderr, "Symbol %s too long for kallsyms (%zu >= %d).\n"
+ "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n",
+ name, strlen(name), KSYM_NAME_LEN);
+ return NULL;
+ }
+
+ if (strcmp(name, "_text") == 0)
+ _text = addr;
+
+ /* Ignore most absolute/undefined (?) symbols. */
+ if (is_ignored_symbol(name, type))
+ return NULL;
+
+ check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges));
+ check_symbol_range(name, addr, &percpu_range, 1);
+
+ /* include the type field in the symbol name, so that it gets
+ * compressed together */
+
+ len = strlen(name) + 1;
+
+ sym = malloc(sizeof(*sym) + len + 1);
+ if (!sym) {
+ fprintf(stderr, "kallsyms failure: "
+ "unable to allocate required amount of memory\n");
+ exit(EXIT_FAILURE);
+ }
+ sym->addr = addr;
+ sym->len = len;
+ sym->sym[0] = type;
+ strcpy(sym_name(sym), name);
+ sym->percpu_absolute = 0;
+
+ return sym;
+}
+
+static int symbol_in_range(const struct sym_entry *s,
+ const struct addr_range *ranges, int entries)
+{
+ size_t i;
+ const struct addr_range *ar;
+
+ for (i = 0; i < entries; ++i) {
+ ar = &ranges[i];
+
+ if (s->addr >= ar->start && s->addr <= ar->end)
+ return 1;
+ }
+
+ return 0;
+}
+
+static int symbol_valid(const struct sym_entry *s)
+{
+ const char *name = sym_name(s);
+
+ /* if --all-symbols is not specified, then symbols outside the text
+ * and inittext sections are discarded */
+ if (!all_symbols) {
+ if (symbol_in_range(s, text_ranges,
+ ARRAY_SIZE(text_ranges)) == 0)
+ return 0;
+ /* Corner case. Discard any symbols with the same value as
+ * _etext _einittext; they can move between pass 1 and 2 when
+ * the kallsyms data are added. If these symbols move then
+ * they may get dropped in pass 2, which breaks the kallsyms
+ * rules.
+ */
+ if ((s->addr == text_range_text->end &&
+ strcmp(name, text_range_text->end_sym)) ||
+ (s->addr == text_range_inittext->end &&
+ strcmp(name, text_range_inittext->end_sym)))
+ return 0;
+ }
+
+ return 1;
+}
+
+/* remove all the invalid symbols from the table */
+static void shrink_table(void)
+{
+ unsigned int i, pos;
+
+ pos = 0;
+ for (i = 0; i < table_cnt; i++) {
+ if (symbol_valid(table[i])) {
+ if (pos != i)
+ table[pos] = table[i];
+ pos++;
+ } else {
+ free(table[i]);
+ }
+ }
+ table_cnt = pos;
+
+ /* When valid symbol is not registered, exit to error */
+ if (!table_cnt) {
+ fprintf(stderr, "No valid symbol.\n");
+ exit(1);
+ }
+}
+
+static void read_map(FILE *in)
+{
+ struct sym_entry *sym;
+
+ while (!feof(in)) {
+ sym = read_symbol(in);
+ if (!sym)
+ continue;
+
+ sym->start_pos = table_cnt;
+
+ if (table_cnt >= table_size) {
+ table_size += 10000;
+ table = realloc(table, sizeof(*table) * table_size);
+ if (!table) {
+ fprintf(stderr, "out of memory\n");
+ exit (1);
+ }
+ }
+
+ table[table_cnt++] = sym;
+ }
+}
+
+static void output_label(const char *label)
+{
+ printf(".globl %s\n", label);
+ printf("\tALGN\n");
+ printf("%s:\n", label);
+}
+
+/* Provide proper symbols relocatability by their '_text' relativeness. */
+static void output_address(unsigned long long addr)
+{
+ if (_text <= addr)
+ printf("\tPTR\t_text + %#llx\n", addr - _text);
+ else
+ printf("\tPTR\t_text - %#llx\n", _text - addr);
+}
+
+/* uncompress a compressed symbol. When this function is called, the best table
+ * might still be compressed itself, so the function needs to be recursive */
+static int expand_symbol(const unsigned char *data, int len, char *result)
+{
+ int c, rlen, total=0;
+
+ while (len) {
+ c = *data;
+ /* if the table holds a single char that is the same as the one
+ * we are looking for, then end the search */
+ if (best_table[c][0]==c && best_table_len[c]==1) {
+ *result++ = c;
+ total++;
+ } else {
+ /* if not, recurse and expand */
+ rlen = expand_symbol(best_table[c], best_table_len[c], result);
+ total += rlen;
+ result += rlen;
+ }
+ data++;
+ len--;
+ }
+ *result=0;
+
+ return total;
+}
+
+static int symbol_absolute(const struct sym_entry *s)
+{
+ return s->percpu_absolute;
+}
+
+static void write_src(void)
+{
+ unsigned int i, k, off;
+ unsigned int best_idx[256];
+ unsigned int *markers;
+ char buf[KSYM_NAME_LEN];
+
+ printf("#include <asm/bitsperlong.h>\n");
+ printf("#if BITS_PER_LONG == 64\n");
+ printf("#define PTR .quad\n");
+ printf("#define ALGN .balign 8\n");
+ printf("#else\n");
+ printf("#define PTR .long\n");
+ printf("#define ALGN .balign 4\n");
+ printf("#endif\n");
+
+ printf("\t.section .rodata, \"a\"\n");
+
+ if (!base_relative)
+ output_label("kallsyms_addresses");
+ else
+ output_label("kallsyms_offsets");
+
+ for (i = 0; i < table_cnt; i++) {
+ if (base_relative) {
+ /*
+ * Use the offset relative to the lowest value
+ * encountered of all relative symbols, and emit
+ * non-relocatable fixed offsets that will be fixed
+ * up at runtime.
+ */
+
+ long long offset;
+ int overflow;
+
+ if (!absolute_percpu) {
+ offset = table[i]->addr - relative_base;
+ overflow = (offset < 0 || offset > UINT_MAX);
+ } else if (symbol_absolute(table[i])) {
+ offset = table[i]->addr;
+ overflow = (offset < 0 || offset > INT_MAX);
+ } else {
+ offset = relative_base - table[i]->addr - 1;
+ overflow = (offset < INT_MIN || offset >= 0);
+ }
+ if (overflow) {
+ fprintf(stderr, "kallsyms failure: "
+ "%s symbol value %#llx out of range in relative mode\n",
+ symbol_absolute(table[i]) ? "absolute" : "relative",
+ table[i]->addr);
+ exit(EXIT_FAILURE);
+ }
+ printf("\t.long\t%#x\n", (int)offset);
+ } else if (!symbol_absolute(table[i])) {
+ output_address(table[i]->addr);
+ } else {
+ printf("\tPTR\t%#llx\n", table[i]->addr);
+ }
+ }
+ printf("\n");
+
+ if (base_relative) {
+ output_label("kallsyms_relative_base");
+ output_address(relative_base);
+ printf("\n");
+ }
+
+ output_label("kallsyms_num_syms");
+ printf("\t.long\t%u\n", table_cnt);
+ printf("\n");
+
+ /* table of offset markers, that give the offset in the compressed stream
+ * every 256 symbols */
+ markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
+ if (!markers) {
+ fprintf(stderr, "kallsyms failure: "
+ "unable to allocate required memory\n");
+ exit(EXIT_FAILURE);
+ }
+
+ output_label("kallsyms_names");
+ off = 0;
+ for (i = 0; i < table_cnt; i++) {
+ if ((i & 0xFF) == 0)
+ markers[i >> 8] = off;
+
+ printf("\t.byte 0x%02x", table[i]->len);
+ for (k = 0; k < table[i]->len; k++)
+ printf(", 0x%02x", table[i]->sym[k]);
+ printf("\n");
+
+ off += table[i]->len + 1;
+ }
+ printf("\n");
+
+ output_label("kallsyms_markers");
+ for (i = 0; i < ((table_cnt + 255) >> 8); i++)
+ printf("\t.long\t%u\n", markers[i]);
+ printf("\n");
+
+ free(markers);
+
+ output_label("kallsyms_token_table");
+ off = 0;
+ for (i = 0; i < 256; i++) {
+ best_idx[i] = off;
+ expand_symbol(best_table[i], best_table_len[i], buf);
+ printf("\t.asciz\t\"%s\"\n", buf);
+ off += strlen(buf) + 1;
+ }
+ printf("\n");
+
+ output_label("kallsyms_token_index");
+ for (i = 0; i < 256; i++)
+ printf("\t.short\t%d\n", best_idx[i]);
+ printf("\n");
+}
+
+
+/* table lookup compression functions */
+
+/* count all the possible tokens in a symbol */
+static void learn_symbol(const unsigned char *symbol, int len)
+{
+ int i;
+
+ for (i = 0; i < len - 1; i++)
+ token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
+}
+
+/* decrease the count for all the possible tokens in a symbol */
+static void forget_symbol(const unsigned char *symbol, int len)
+{
+ int i;
+
+ for (i = 0; i < len - 1; i++)
+ token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
+}
+
+/* do the initial token count */
+static void build_initial_tok_table(void)
+{
+ unsigned int i;
+
+ for (i = 0; i < table_cnt; i++)
+ learn_symbol(table[i]->sym, table[i]->len);
+}
+
+static unsigned char *find_token(unsigned char *str, int len,
+ const unsigned char *token)
+{
+ int i;
+
+ for (i = 0; i < len - 1; i++) {
+ if (str[i] == token[0] && str[i+1] == token[1])
+ return &str[i];
+ }
+ return NULL;
+}
+
+/* replace a given token in all the valid symbols. Use the sampled symbols
+ * to update the counts */
+static void compress_symbols(const unsigned char *str, int idx)
+{
+ unsigned int i, len, size;
+ unsigned char *p1, *p2;
+
+ for (i = 0; i < table_cnt; i++) {
+
+ len = table[i]->len;
+ p1 = table[i]->sym;
+
+ /* find the token on the symbol */
+ p2 = find_token(p1, len, str);
+ if (!p2) continue;
+
+ /* decrease the counts for this symbol's tokens */
+ forget_symbol(table[i]->sym, len);
+
+ size = len;
+
+ do {
+ *p2 = idx;
+ p2++;
+ size -= (p2 - p1);
+ memmove(p2, p2 + 1, size);
+ p1 = p2;
+ len--;
+
+ if (size < 2) break;
+
+ /* find the token on the symbol */
+ p2 = find_token(p1, size, str);
+
+ } while (p2);
+
+ table[i]->len = len;
+
+ /* increase the counts for this symbol's new tokens */
+ learn_symbol(table[i]->sym, len);
+ }
+}
+
+/* search the token with the maximum profit */
+static int find_best_token(void)
+{
+ int i, best, bestprofit;
+
+ bestprofit=-10000;
+ best = 0;
+
+ for (i = 0; i < 0x10000; i++) {
+ if (token_profit[i] > bestprofit) {
+ best = i;
+ bestprofit = token_profit[i];
+ }
+ }
+ return best;
+}
+
+/* this is the core of the algorithm: calculate the "best" table */
+static void optimize_result(void)
+{
+ int i, best;
+
+ /* using the '\0' symbol last allows compress_symbols to use standard
+ * fast string functions */
+ for (i = 255; i >= 0; i--) {
+
+ /* if this table slot is empty (it is not used by an actual
+ * original char code */
+ if (!best_table_len[i]) {
+
+ /* find the token with the best profit value */
+ best = find_best_token();
+ if (token_profit[best] == 0)
+ break;
+
+ /* place it in the "best" table */
+ best_table_len[i] = 2;
+ best_table[i][0] = best & 0xFF;
+ best_table[i][1] = (best >> 8) & 0xFF;
+
+ /* replace this token in all the valid symbols */
+ compress_symbols(best_table[i], i);
+ }
+ }
+}
+
+/* start by placing the symbols that are actually used on the table */
+static void insert_real_symbols_in_table(void)
+{
+ unsigned int i, j, c;
+
+ for (i = 0; i < table_cnt; i++) {
+ for (j = 0; j < table[i]->len; j++) {
+ c = table[i]->sym[j];
+ best_table[c][0]=c;
+ best_table_len[c]=1;
+ }
+ }
+}
+
+static void optimize_token_table(void)
+{
+ build_initial_tok_table();
+
+ insert_real_symbols_in_table();
+
+ optimize_result();
+}
+
+/* guess for "linker script provide" symbol */
+static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
+{
+ const char *symbol = sym_name(se);
+ int len = se->len - 1;
+
+ if (len < 8)
+ return 0;
+
+ if (symbol[0] != '_' || symbol[1] != '_')
+ return 0;
+
+ /* __start_XXXXX */
+ if (!memcmp(symbol + 2, "start_", 6))
+ return 1;
+
+ /* __stop_XXXXX */
+ if (!memcmp(symbol + 2, "stop_", 5))
+ return 1;
+
+ /* __end_XXXXX */
+ if (!memcmp(symbol + 2, "end_", 4))
+ return 1;
+
+ /* __XXXXX_start */
+ if (!memcmp(symbol + len - 6, "_start", 6))
+ return 1;
+
+ /* __XXXXX_end */
+ if (!memcmp(symbol + len - 4, "_end", 4))
+ return 1;
+
+ return 0;
+}
+
+static int compare_symbols(const void *a, const void *b)
+{
+ const struct sym_entry *sa = *(const struct sym_entry **)a;
+ const struct sym_entry *sb = *(const struct sym_entry **)b;
+ int wa, wb;
+
+ /* sort by address first */
+ if (sa->addr > sb->addr)
+ return 1;
+ if (sa->addr < sb->addr)
+ return -1;
+
+ /* sort by "weakness" type */
+ wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
+ wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
+ if (wa != wb)
+ return wa - wb;
+
+ /* sort by "linker script provide" type */
+ wa = may_be_linker_script_provide_symbol(sa);
+ wb = may_be_linker_script_provide_symbol(sb);
+ if (wa != wb)
+ return wa - wb;
+
+ /* sort by the number of prefix underscores */
+ wa = strspn(sym_name(sa), "_");
+ wb = strspn(sym_name(sb), "_");
+ if (wa != wb)
+ return wa - wb;
+
+ /* sort by initial order, so that other symbols are left undisturbed */
+ return sa->start_pos - sb->start_pos;
+}
+
+static void sort_symbols(void)
+{
+ qsort(table, table_cnt, sizeof(table[0]), compare_symbols);
+}
+
+static void make_percpus_absolute(void)
+{
+ unsigned int i;
+
+ for (i = 0; i < table_cnt; i++)
+ if (symbol_in_range(table[i], &percpu_range, 1)) {
+ /*
+ * Keep the 'A' override for percpu symbols to
+ * ensure consistent behavior compared to older
+ * versions of this tool.
+ */
+ table[i]->sym[0] = 'A';
+ table[i]->percpu_absolute = 1;
+ }
+}
+
+/* find the minimum non-absolute symbol address */
+static void record_relative_base(void)
+{
+ unsigned int i;
+
+ for (i = 0; i < table_cnt; i++)
+ if (!symbol_absolute(table[i])) {
+ /*
+ * The table is sorted by address.
+ * Take the first non-absolute symbol value.
+ */
+ relative_base = table[i]->addr;
+ return;
+ }
+}
+
+int main(int argc, char **argv)
+{
+ if (argc >= 2) {
+ int i;
+ for (i = 1; i < argc; i++) {
+ if(strcmp(argv[i], "--all-symbols") == 0)
+ all_symbols = 1;
+ else if (strcmp(argv[i], "--absolute-percpu") == 0)
+ absolute_percpu = 1;
+ else if (strcmp(argv[i], "--base-relative") == 0)
+ base_relative = 1;
+ else
+ usage();
+ }
+ } else if (argc != 1)
+ usage();
+
+ read_map(stdin);
+ shrink_table();
+ if (absolute_percpu)
+ make_percpus_absolute();
+ sort_symbols();
+ if (base_relative)
+ record_relative_base();
+ optimize_token_table();
+ write_src();
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-30 09:23:37 +0000