[PATCH 1/1] fentry: x86, cleanup function_hook uses

[Jiri Slaby <jslaby@suse.cz>]

Let's define fentry_hook depending on CC_USING_FENTRY and use that
macro all over. This saves some #ifdef's here and there.

We do not use the old macro function_hook since it is too generic.
Hence we introduce fentry_hook which corresponds to what it is.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
---
 arch/x86/include/asm/fentry.h    | 14 ++++++++++++++
 arch/x86/include/asm/ftrace.h    | 11 ++++-------
 arch/x86/kernel/mcount_64.S      | 15 +++++----------
 arch/x86/kernel/x8664_ksyms_64.c |  8 ++------
 4 files changed, 25 insertions(+), 23 deletions(-)
 create mode 100644 arch/x86/include/asm/fentry.h

diff --git a/arch/x86/include/asm/fentry.h b/arch/x86/include/asm/fentry.h
new file mode 100644
index 000000000000..febe8d272f0f
--- /dev/null
+++ b/arch/x86/include/asm/fentry.h
@@ -0,0 +1,14 @@
+#ifndef ASM_FENTRY_H
+#define ASM_FENTRY_H
+
+#ifdef CC_USING_FENTRY
+# define fentry_hook	__fentry__
+#else
+# define fentry_hook	mcount
+#endif
+
+#ifndef __ASSEMBLY__
+extern void fentry_hook(void);
+#endif /* __ASSEMBLY__ */
+
+#endif /* ASM_FENTRY_H */
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 24938852db30..dc235b3659da 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -2,11 +2,10 @@
 #define _ASM_X86_FTRACE_H
 
 #ifdef CONFIG_FUNCTION_TRACER
-#ifdef CC_USING_FENTRY
-# define MCOUNT_ADDR		((unsigned long)(__fentry__))
-#else
-# define MCOUNT_ADDR		((unsigned long)(mcount))
-#endif
+
+#include <asm/fentry.h>
+
+#define MCOUNT_ADDR		((unsigned long)(fentry_hook))
 #define MCOUNT_INSN_SIZE	5 /* sizeof mcount call */
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -14,9 +13,7 @@
 #endif
 
 #ifndef __ASSEMBLY__
-extern void mcount(void);
 extern atomic_t modifying_ftrace_code;
-extern void __fentry__(void);
 
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
index 94ea120fa21f..ac8d5296d6ec 100644
--- a/arch/x86/kernel/mcount_64.S
+++ b/arch/x86/kernel/mcount_64.S
@@ -6,6 +6,7 @@
 
 #include <linux/linkage.h>
 #include <asm/ptrace.h>
+#include <asm/fentry.h>
 #include <asm/ftrace.h>
 
 
@@ -15,12 +16,6 @@
 
 #ifdef CONFIG_FUNCTION_TRACER
 
-#ifdef CC_USING_FENTRY
-# define function_hook	__fentry__
-#else
-# define function_hook	mcount
-#endif
-
 /* All cases save the original rbp (8 bytes) */
 #ifdef CONFIG_FRAME_POINTER
 # ifdef CC_USING_FENTRY
@@ -147,9 +142,9 @@
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
-ENTRY(function_hook)
+ENTRY(fentry_hook)
 	retq
-END(function_hook)
+END(fentry_hook)
 
 ENTRY(ftrace_caller)
 	/* save_mcount_regs fills in first two parameters */
@@ -258,7 +253,7 @@ END(ftrace_regs_caller)
 
 #else /* ! CONFIG_DYNAMIC_FTRACE */
 
-ENTRY(function_hook)
+ENTRY(fentry_hook)
 	cmpq $ftrace_stub, ftrace_trace_function
 	jnz trace
 
@@ -283,7 +278,7 @@ trace:
 	restore_mcount_regs
 
 	jmp fgraph_trace
-END(function_hook)
+END(fentry_hook)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 #endif /* CONFIG_FUNCTION_TRACER */
 
diff --git a/arch/x86/kernel/x8664_ksyms_64.c b/arch/x86/kernel/x8664_ksyms_64.c
index a0695be19864..5607abc110c7 100644
--- a/arch/x86/kernel/x8664_ksyms_64.c
+++ b/arch/x86/kernel/x8664_ksyms_64.c
@@ -10,15 +10,11 @@
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 #include <asm/desc.h>
-#include <asm/ftrace.h>
+#include <asm/fentry.h>
 
 #ifdef CONFIG_FUNCTION_TRACER
 /* mcount and __fentry__ are defined in assembly */
-#ifdef CC_USING_FENTRY
-EXPORT_SYMBOL(__fentry__);
-#else
-EXPORT_SYMBOL(mcount);
-#endif
+EXPORT_SYMBOL(fentry_hook);
 #endif
 
 EXPORT_SYMBOL(__get_user_1);
-- 
2.6.1