#include <stdlib.h>
#include <string.h>
#include <ctype.h>
+#include <limits.h>
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
unsigned int len;
unsigned int start_pos;
unsigned char *sym;
+ unsigned int percpu_absolute;
};
struct addr_range {
};
static unsigned long long _text;
+static unsigned long long relative_base;
static struct addr_range text_ranges[] = {
{ "_stext", "_etext" },
{ "_sinittext", "_einittext" },
static int absolute_percpu = 0;
static char symbol_prefix_char = '\0';
static unsigned long long kernel_start_addr = 0;
+static int base_relative = 0;
int token_profit[0x10000];
fprintf(stderr, "Usage: kallsyms [--all-symbols] "
"[--symbol-prefix=<prefix char>] "
"[--page-offset=<CONFIG_PAGE_OFFSET>] "
- "< in.map > out.S\n");
+ "[--base-relative] < in.map > out.S\n");
exit(1);
}
strcpy((char *)s->sym + 1, str);
s->sym[0] = stype;
+ s->percpu_absolute = 0;
+
/* Record if we've found __per_cpu_start/end. */
check_symbol_range(sym, s->addr, &percpu_range, 1);
*/
static char *special_symbols[] = {
"kallsyms_addresses",
+ "kallsyms_offsets",
+ "kallsyms_relative_base",
"kallsyms_num_syms",
"kallsyms_names",
"kallsyms_markers",
static int symbol_absolute(struct sym_entry *s)
{
- return toupper(s->sym[0]) == 'A';
+ return s->percpu_absolute;
}
static void write_src(void)
printf("\t.section .rodata, \"a\"\n");
- /* Provide proper symbols relocatability by their '_text'
- * relativeness. The symbol names cannot be used to construct
- * normal symbol references as the list of symbols contains
- * symbols that are declared static and are private to their
- * .o files. This prevents .tmp_kallsyms.o or any other
- * object from referencing them.
+ /* Provide proper symbols relocatability by their relativeness
+ * to a fixed anchor point in the runtime image, either '_text'
+ * for absolute address tables, in which case the linker will
+ * emit the final addresses at build time. Otherwise, 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.
+ *
+ * The symbol names cannot be used to construct normal symbol
+ * references as the list of symbols contains symbols that are
+ * declared static and are private to their .o files. This prevents
+ * .tmp_kallsyms.o or any other object from referencing them.
*/
- output_label("kallsyms_addresses");
+ if (!base_relative)
+ output_label("kallsyms_addresses");
+ else
+ output_label("kallsyms_offsets");
+
for (i = 0; i < table_cnt; i++) {
- if (!symbol_absolute(&table[i])) {
+ if (base_relative) {
+ 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])) {
if (_text <= table[i].addr)
printf("\tPTR\t_text + %#llx\n",
table[i].addr - _text);
}
printf("\n");
+ if (base_relative) {
+ output_label("kallsyms_relative_base");
+ printf("\tPTR\t_text - %#llx\n", _text - relative_base);
+ printf("\n");
+ }
+
output_label("kallsyms_num_syms");
printf("\tPTR\t%d\n", table_cnt);
printf("\n");
unsigned int i;
for (i = 0; i < table_cnt; i++)
- if (symbol_in_range(&table[i], &percpu_range, 1))
+ 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;
+
+ relative_base = -1ULL;
+ for (i = 0; i < table_cnt; i++)
+ if (!symbol_absolute(&table[i]) &&
+ table[i].addr < relative_base)
+ relative_base = table[i].addr;
}
int main(int argc, char **argv)
} else if (strncmp(argv[i], "--page-offset=", 14) == 0) {
const char *p = &argv[i][14];
kernel_start_addr = strtoull(p, NULL, 16);
- } else
+ } else if (strcmp(argv[i], "--base-relative") == 0)
+ base_relative = 1;
+ else
usage();
}
} else if (argc != 1)
read_map(stdin);
if (absolute_percpu)
make_percpus_absolute();
+ if (base_relative)
+ record_relative_base();
sort_symbols();
optimize_token_table();
write_src();