@@ -579,7 +579,8 @@ struct module *find_module(const char *name);
/* Returns 0 and fills in value, defined and namebuf, or -ERANGE if
symnum out of range. */
int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
- char *name, char *module_name, int *exported);
+ char *name, char *module_name, unsigned long *size,
+ int *exported);
/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name);
@@ -756,8 +757,8 @@ static inline int lookup_module_symbol_attrs(unsigned long addr, unsigned long *
}
static inline int module_get_kallsym(unsigned int symnum, unsigned long *value,
- char *type, char *name,
- char *module_name, int *exported)
+ char *type, char *name, char *module_name,
+ unsigned long *size, int *exported)
{
return -ERANGE;
}
@@ -33,6 +33,7 @@
*/
extern const unsigned long kallsyms_addresses[] __weak;
extern const int kallsyms_offsets[] __weak;
+extern const unsigned long kallsyms_sizes[] __weak;
extern const u8 kallsyms_names[] __weak;
/*
@@ -254,12 +255,24 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
}
#endif /* CONFIG_LIVEPATCH */
+/*
+ * The caller passes in an address, and we return an index to the symbol --
+ * potentially also size and offset information.
+ * But an address might map to multiple symbols because:
+ * - some symbols might have zero size
+ * - some symbols might be aliases of one another
+ * - some symbols might span (encompass) others
+ * The symbols should already be ordered so that, for a particular address,
+ * we first have the zero-size ones, then the biggest, then the smallest.
+ * So we find the index by:
+ * - finding the last symbol with the target address
+ * - backing the index up so long as both the address and size are unchanged
+ */
static unsigned long get_symbol_pos(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset)
{
- unsigned long symbol_start = 0, symbol_end = 0;
- unsigned long i, low, high, mid;
+ unsigned long low, high, mid;
/* This kernel should never had been booted. */
if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
@@ -280,36 +293,17 @@ static unsigned long get_symbol_pos(unsigned long addr,
}
/*
- * Search for the first aliased symbol. Aliased
- * symbols are symbols with the same address.
+ * Search for the first aliased symbol.
*/
- while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
+ while (low
+ && kallsyms_sym_address(low-1) == kallsyms_sym_address(low)
+ && kallsyms_sizes[low-1] == kallsyms_sizes[low])
--low;
- symbol_start = kallsyms_sym_address(low);
-
- /* Search for next non-aliased symbol. */
- for (i = low + 1; i < kallsyms_num_syms; i++) {
- if (kallsyms_sym_address(i) > symbol_start) {
- symbol_end = kallsyms_sym_address(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 if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
- symbol_end = (unsigned long)_end;
- else
- symbol_end = (unsigned long)_etext;
- }
-
if (symbolsize)
- *symbolsize = symbol_end - symbol_start;
+ *symbolsize = kallsyms_sizes[low];
if (offset)
- *offset = addr - symbol_start;
+ *offset = addr - kallsyms_sym_address(low);
return low;
}
@@ -569,6 +563,7 @@ struct kallsym_iter {
loff_t pos_bpf_end;
unsigned long value;
unsigned int nameoff; /* If iterating in core kernel symbols. */
+ unsigned long size;
char type;
char name[KSYM_NAME_LEN];
char module_name[MODULE_NAME_LEN];
@@ -603,7 +598,7 @@ static int get_ksymbol_mod(struct kallsym_iter *iter)
int ret = module_get_kallsym(iter->pos - iter->pos_arch_end,
&iter->value, &iter->type,
iter->name, iter->module_name,
- &iter->exported);
+ &iter->size, &iter->exported);
iter->builtin_module_names = NULL;
if (ret < 0) {
@@ -677,6 +672,7 @@ static unsigned long get_ksymbol_core(struct kallsym_iter *iter, int kallmodsyms
iter->exported = 0;
iter->value = kallsyms_sym_address(iter->pos);
+ iter->size = kallsyms_sizes[iter->pos];
iter->type = kallsyms_get_symbol_type(off);
iter->module_name[0] = '\0';
@@ -793,12 +789,14 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms)
{
void *value;
struct kallsym_iter *iter = m->private;
+ unsigned long size;
/* Some debugging symbols have no name. Ignore them. */
if (!iter->name[0])
return 0;
value = iter->show_value ? (void *)iter->value : NULL;
+ size = iter->show_value ? iter->size : 0;
/*
* Real module, or built-in module and /proc/kallsyms being shown.
@@ -818,15 +816,15 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms)
* /proc/kallmodsyms, built as a module.
*/
if (iter->builtin_module_names == NULL)
- seq_printf(m, "%px %c %s\t[%s]\n", value,
- type, iter->name,
+ seq_printf(m, "%px %lx %c %s\t[%s]\n", value,
+ size, type, iter->name,
iter->module_name);
/*
* /proc/kallmodsyms, single-module symbol.
*/
else if (*iter->builtin_module_names != '\0')
- seq_printf(m, "%px %c %s\t[%s]\n", value,
- type, iter->name,
+ seq_printf(m, "%px %lx %c %s\t[%s]\n", value,
+ size, type, iter->name,
iter->builtin_module_names);
/*
* /proc/kallmodsyms, multimodule symbol. Formatted
@@ -837,8 +835,8 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms)
size_t i = *(char *)(iter->builtin_module_names + 1);
const char *walk = iter->builtin_module_names + 2;
- seq_printf(m, "%px %c %s\t[%s]", value,
- type, iter->name, walk);
+ seq_printf(m, "%px %lx %c %s\t[%s]", value,
+ size, type, iter->name, walk);
while (--i > 0) {
walk += strlen(walk) + 1;
@@ -850,7 +848,13 @@ static int s_show_internal(struct seq_file *m, void *p, int kallmodsyms)
#endif /* CONFIG_KALLMODSYMS */
seq_printf(m, "%px %c %s\t[%s]\n", value,
type, iter->name, iter->module_name);
- } else
+ /*
+ * Non-modular, /proc/kallmodsyms -> print size.
+ */
+ } else if (kallmodsyms)
+ seq_printf(m, "%px %lx %c %s\n", value, size,
+ iter->type, iter->name);
+ else
seq_printf(m, "%px %c %s\n", value,
iter->type, iter->name);
return 0;
@@ -4332,7 +4332,8 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
}
int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
- char *name, char *module_name, int *exported)
+ char *name, char *module_name, unsigned long *size,
+ int *exported)
{
struct module *mod;
@@ -4351,6 +4352,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
strlcpy(module_name, mod->name, MODULE_NAME_LEN);
*exported = is_exported(name, *value, mod);
+ *size = kallsyms->symtab[symnum].st_size;
preempt_enable();
return 0;
}
@@ -5,7 +5,7 @@
* 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
+ * Usage: nm -n -S vmlinux
* | scripts/kallsyms [--all-symbols] [--absolute-percpu]
* [--base-relative] [--builtin=modules_thick.builtin]
* > symbols.S
@@ -38,6 +38,7 @@
struct sym_entry {
unsigned long long addr;
+ unsigned long long size;
unsigned int len;
unsigned int start_pos;
unsigned int percpu_absolute;
@@ -394,6 +395,7 @@ static bool is_ignored_symbol(const char *name, char type)
"kallsyms_addresses",
"kallsyms_offsets",
"kallsyms_relative_base",
+ "kallsyms_sizes",
"kallsyms_num_syms",
"kallsyms_num_modules",
"kallsyms_names",
@@ -507,10 +509,11 @@ static struct sym_entry *read_symbol(FILE *in)
unsigned long long addr;
unsigned int len;
struct sym_entry *sym;
- int rc;
+ int rc = 0;
+ unsigned long long size;
- rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
- if (rc != 3) {
+ rc = fscanf(in, "%llx %llx %c %499s\n", &addr, &size, &type, name);
+ if (rc != 4) {
if (rc != EOF && fgets(name, 500, in) == NULL)
fprintf(stderr, "Read error or end of file.\n");
return NULL;
@@ -548,6 +551,7 @@ static struct sym_entry *read_symbol(FILE *in)
sym->sym[0] = type;
strcpy(sym_name(sym), name);
sym->percpu_absolute = 0;
+ sym->size = size;
return sym;
}
@@ -932,6 +936,11 @@ static void write_src(void)
printf("\n");
}
+ output_label("kallsyms_sizes");
+ for (i = 0; i < table_cnt; i++)
+ printf("\tPTR\t%#llx\n", table[i]->size);
+ printf("\n");
+
#ifdef CONFIG_KALLMODSYMS
output_kallmodsyms_modules();
output_kallmodsyms_objfiles();
@@ -1189,6 +1198,18 @@ static int compare_symbols(const void *a, const void *b)
if (sa->addr < sb->addr)
return -1;
+ /* zero-size markers before nonzero-size symbols */
+ if (sa->size > 0 && sb->size == 0)
+ return 1;
+ if (sa->size == 0 && sb->size > 0)
+ return -1;
+
+ /* sort by size (large size preceding symbols it encompasses) */
+ if (sa->size < sb->size)
+ return 1;
+ if (sa->size > sb->size)
+ return -1;
+
/* sort by "weakness" type */
wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
@@ -288,7 +288,12 @@ kallsyms()
fi
info KSYMS ${2}
- ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2}
+ # "nm -S" does not print symbol size when size is 0
+ # Therefore use awk to regularize the data:
+ # - when there are only three fields, add an explicit "0"
+ # - when there are already four fields, pass through as is
+ ${NM} -n -S ${1} | ${AWK} 'NF==3 {print $1, 0, $2, $3}; NF==4' | \
+ scripts/kallsyms ${kallsymopt} > ${2}
}
# Perform one step in kallsyms generation, including temporary linking of