microblaze: Fix ftrace

- Do not trace idle loop which takes a lot time
- Fix cache handling in generic ftrace code
- Do not trace lib functions ashldi3, ashrdi3, lshrdi3
  Functions are called from generic ftrace code which
  can't be traced
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/kernel/Makefile

@@ -10,6 +10,7 @@ CFLAGS_REMOVE_early_printk.o = -pg
 CFLAGS_REMOVE_selfmod.o = -pg
 CFLAGS_REMOVE_heartbeat.o = -pg
 CFLAGS_REMOVE_ftrace.o = -pg
+CFLAGS_REMOVE_process.o = -pg
 endif
 
 extra-y := head.o vmlinux.lds

arch/microblaze/kernel/ftrace.c

@@ -51,6 +51,9 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 			: "r" (parent), "r" (return_hooker)
 	);
 
+	flush_dcache_range((u32)parent, (u32)parent + 4);
+	flush_icache_range((u32)parent, (u32)parent + 4);
+
 	if (unlikely(faulted)) {
 		ftrace_graph_stop();
 		WARN_ON(1);
@@ -95,6 +98,9 @@ static int ftrace_modify_code(unsigned long addr, unsigned int value)
 	if (unlikely(faulted))
 		return -EFAULT;
 
+	flush_dcache_range(addr, addr + 4);
+	flush_icache_range(addr, addr + 4);
+
 	return 0;
 }
 
@@ -195,8 +201,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	ret += ftrace_modify_code((unsigned long)&ftrace_caller,
 				  MICROBLAZE_NOP);
 
-	/* All changes are done - lets do caches consistent */
-	flush_icache();
 	return ret;
 }
 
@@ -210,7 +214,6 @@ int ftrace_enable_ftrace_graph_caller(void)
 
 	old_jump = *(unsigned int *)ip; /* save jump over instruction */
 	ret = ftrace_modify_code(ip, MICROBLAZE_NOP);
-	flush_icache();
 
 	pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);
 	return ret;
@@ -222,7 +225,6 @@ int ftrace_disable_ftrace_graph_caller(void)
 	unsigned long ip = (unsigned long)(&ftrace_call_graph);
 
 	ret = ftrace_modify_code(ip, old_jump);
-	flush_icache();
 
 	pr_debug("%s\n", __func__);
 	return ret;

arch/microblaze/lib/Makefile

@@ -2,6 +2,12 @@
 # Makefile
 #
 
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_ashldi3.o = -pg
+CFLAGS_REMOVE_ashrdi3.o = -pg
+CFLAGS_REMOVE_lshrdi3.o = -pg
+endif
+
 lib-y :=  memset.o
 
 ifeq ($(CONFIG_OPT_LIB_ASM),y)