powerpc/ppc32: ftrace, dynamic ftrace to handle modules

Impact: add ability to trace modules on 32 bit PowerPC

This patch performs the necessary trampoline calls to handle
modules with dynamic ftrace on 32 bit PowerPC.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c
index 2df91a03462a..f832773fc28e 100644
--- a/arch/powerpc/kernel/module_32.c
+++ b/arch/powerpc/kernel/module_32.c
@@ -22,6 +22,7 @@
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
+#include <linux/ftrace.h>
 #include <linux/cache.h>
 #include <linux/bug.h>
 #include <linux/sort.h>
@@ -53,6 +54,9 @@ static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
                         r_addend = rela[i].r_addend;
                 }
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+        _count_relocs++;        /* add one for ftrace_caller */
+#endif
         return _count_relocs;
 }
 
@@ -306,5 +310,11 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
                         return -ENOEXEC;
                 }
         }
+#ifdef CONFIG_DYNAMIC_FTRACE
+        module->arch.tramp =
+                do_plt_call(module->module_core,
+                            (unsigned long)ftrace_caller,
+                            sechdrs, module);
+#endif
         return 0;
 }