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-rw-r--r--include/linux/ftrace.h6
-rw-r--r--kernel/kallsyms.c1
-rw-r--r--kernel/trace/ftrace.c62
3 files changed, 69 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 4816b7e11047..820500430eae 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -303,6 +303,8 @@ int unregister_ftrace_function(struct ftrace_ops *ops);
extern void ftrace_stub(unsigned long a0, unsigned long a1,
struct ftrace_ops *op, struct ftrace_regs *fregs);
+
+int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs);
#else /* !CONFIG_FUNCTION_TRACER */
/*
* (un)register_ftrace_function must be a macro since the ops parameter
@@ -313,6 +315,10 @@ extern void ftrace_stub(unsigned long a0, unsigned long a1,
static inline void ftrace_kill(void) { }
static inline void ftrace_free_init_mem(void) { }
static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
+static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_FUNCTION_TRACER */
struct ftrace_func_entry {
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fdfd308bebc4..fbdf8d3279ac 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -29,6 +29,7 @@
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/kernel.h>
+#include <linux/bsearch.h>
/*
* These will be re-linked against their real values
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4f1d2f5e7263..07d87c7a525d 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7964,3 +7964,65 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
mutex_unlock(&ftrace_lock);
return ret;
}
+
+static int symbols_cmp(const void *a, const void *b)
+{
+ const char **str_a = (const char **) a;
+ const char **str_b = (const char **) b;
+
+ return strcmp(*str_a, *str_b);
+}
+
+struct kallsyms_data {
+ unsigned long *addrs;
+ const char **syms;
+ size_t cnt;
+ size_t found;
+};
+
+static int kallsyms_callback(void *data, const char *name,
+ struct module *mod, unsigned long addr)
+{
+ struct kallsyms_data *args = data;
+
+ if (!bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp))
+ return 0;
+
+ addr = ftrace_location(addr);
+ if (!addr)
+ return 0;
+
+ args->addrs[args->found++] = addr;
+ return args->found == args->cnt ? 1 : 0;
+}
+
+/**
+ * ftrace_lookup_symbols - Lookup addresses for array of symbols
+ *
+ * @sorted_syms: array of symbols pointers symbols to resolve,
+ * must be alphabetically sorted
+ * @cnt: number of symbols/addresses in @syms/@addrs arrays
+ * @addrs: array for storing resulting addresses
+ *
+ * This function looks up addresses for array of symbols provided in
+ * @syms array (must be alphabetically sorted) and stores them in
+ * @addrs array, which needs to be big enough to store at least @cnt
+ * addresses.
+ *
+ * This function returns 0 if all provided symbols are found,
+ * -ESRCH otherwise.
+ */
+int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
+{
+ struct kallsyms_data args;
+ int err;
+
+ args.addrs = addrs;
+ args.syms = sorted_syms;
+ args.cnt = cnt;
+ args.found = 0;
+ err = kallsyms_on_each_symbol(kallsyms_callback, &args);
+ if (err < 0)
+ return err;
+ return args.found == args.cnt ? 0 : -ESRCH;
+}