kprobes: Make kprobe register via symbol name

include/kprobes.h

@@ -34,7 +34,12 @@ typedef int (*kretprobe_handler_t) (struct kprobe *kp, uint32_t *stack,
 				      uint32_t *kp_regs);
 
 struct kprobe {
+	/* location of the probe point */
 	void *addr;
+
+	/* Allow user to indicate symbol name of the probe point */
+	const char *symbol_name;
+
 	kprobe_pre_handler_t pre_handler;
 	kprobe_post_handler_t post_handler;
 	struct breakpoint *bkpt;

include/ksym.h

@@ -19,5 +19,6 @@ int ksym_total(void);
 int ksym_lookup(void *addr);
 char *ksym_id2name(int symid);
 void *ksym_id2addr(int symid);
+void *ksym_lookup_name(const char *name);
 
 #endif /* KSYM_H_ */

kernel/kprobes.c

@@ -3,6 +3,7 @@
  * found in the LICENSE file.
  */
 
+#include <ksym.h>
 #include <kprobes.h>
 #include <platform/armv7m.h>
 #include <platform/breakpoint.h>
@@ -52,9 +53,38 @@ void kplist_del(struct kprobe *kp)
 	}
 }
 
+static void *kprobe_addr(struct kprobe *kp)
+{
+	void *addr = kp->addr;
+
+	/*
+	 * Cannot use address and symbol name at the same time.
+	 * And, you should provide at least one of them.
+	 */
+	if ((kp->addr && kp->symbol_name) ||
+	    (!kp->addr && !kp->symbol_name))
+		return NULL;
+
+	if (kp->symbol_name)
+		addr = ksym_lookup_name(kp->symbol_name);
+
+	addr = (void *)((uint32_t) addr & ~(1UL));
+	if (addr)
+		return addr;
+
+	/* Return NULL when can't found the address of symbol */
+	return NULL;
+}
+
 int kprobe_register(struct kprobe *kp)
 {
-	kp->addr = (void *) ((uint32_t) kp->addr & ~(1UL));
+	void *addr;
+
+	addr = kprobe_addr(kp);
+	if (!addr)
+		return -1;
+
+	kp->addr = addr;
 	if (is_thumb32(*(uint16_t *) kp->addr))
 		kp->step_addr = kp->addr + 4;
 	else

kernel/ksym.c

@@ -6,6 +6,7 @@
 #include <ksym.h>
 #include <types.h>
 #include <lib/stdlib.h>
+#include <lib/string.h>
 #include <init_hook.h>
 #include <platform/link.h>
 
@@ -78,3 +79,15 @@ void *ksym_id2addr(int symid)
 {
 	return __ksym_tbl[symid].addr;
 }
+
+/* Lookup the address for this symbol. Returns 0 if not found. */
+void *ksym_lookup_name(const char *name)
+{
+	for (int i = 0; i < __ksym_count; ++i) {
+		if (strcmp(name, ksym_id2name(i)) == 0) {
+			return ksym_id2addr(i);
+		}
+	}
+
+	return NULL;
+}

kernel/lib/build.mk

@@ -5,6 +5,7 @@
 lib-str-y += \
 	memcpy.o \
 	memset.o \
+	strcmp.o
 
 
 kernel-lib-y += \