Ksplice: Add functions for walking kallsyms symbols

Impact: New API

kallsyms_lookup_name only returns the first match that it finds.  Ksplice
needs information about all symbols with a given name in order to correctly
resolve local symbols.

kallsyms_on_each_symbol provides a generic mechanism for iterating over the
kallsyms table.

Cc: Jeff Arnold <jbarnold@mit.edu>
Cc: Tim Abbott <tabbott@mit.edu>
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

2 files changed, 38 insertions, 0 deletions

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 7b8b0f21a5b1..374faf9bfdc7 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -161,6 +161,25 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
+				      unsigned long),
+			    void *data)
+{
+	char namebuf[KSYM_NAME_LEN];
+	unsigned long i;
+	unsigned int off;
+	int ret;
+
+	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
+		off = kallsyms_expand_symbol(off, namebuf);
+		ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
+		if (ret != 0)
+			return ret;
+	}
+	return module_kallsyms_on_each_symbol(fn, data);
+}
+EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
+
 static unsigned long get_symbol_pos(unsigned long addr,
 				    unsigned long *symbolsize,
 				    unsigned long *offset)
diff --git a/kernel/module.c b/kernel/module.c
index 8ddca629e079..dd4389be9152 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2612,6 +2612,25 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	preempt_enable();
 	return ret;
 }
+
+int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
+					     struct module *, unsigned long),
+				   void *data)
+{
+	struct module *mod;
+	unsigned int i;
+	int ret;
+
+	list_for_each_entry(mod, &modules, list) {
+		for (i = 0; i < mod->num_symtab; i++) {
+			ret = fn(data, mod->strtab + mod->symtab[i].st_name,
+				 mod, mod->symtab[i].st_value);
+			if (ret != 0)
+				return ret;
+		}
+	}
+	return 0;
+}
 #endif /* CONFIG_KALLSYMS */
 
 static char *module_flags(struct module *mod, char *buf)