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)