1 files changed, 15 insertions, 0 deletions

diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h
index 34e1f89a5fa0..1ef54be6abfa 100644
--- a/include/asm-powerpc/kprobes.h
+++ b/include/asm-powerpc/kprobes.h
@@ -44,6 +44,21 @@ typedef unsigned int kprobe_opcode_t;
 #define IS_TDI(instr)           (((instr) & 0xfc000000) == 0x08000000)
 #define IS_TWI(instr)           (((instr) & 0xfc000000) == 0x0c000000)
 
+/*
+ * 64bit powerpc uses function descriptors.
+ * Handle cases where:
+ *              - User passes a <.symbol>
+ *              - User passes a <symbol>
+ *              - User passes a non-existant symbol, kallsyms_lookup_name
+ *                returns 0. Don't deref the NULL pointer in that case
+ */
+#define kprobe_lookup_name(name, addr)                                  \
+{                                                                       \
+        addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);           \
+        if (!(name[0] == '.') && addr)                                  \
+                addr = *(kprobe_opcode_t **)addr;                       \
+}
+
 #define JPROBE_ENTRY(pentry)    (kprobe_opcode_t *)((func_descr_t *)pentry)
 
 #define is_trap(instr)  (IS_TW(instr) || IS_TD(instr) || \