ARM: move ftrace assembly code to separate file

The ftrace assembly code doesn't need to live in entry-common.S and
be surrounded with #ifdef CONFIG_FUNCTION_TRACER.  Instead, move it
to its own file and conditionally assemble it.

Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/Makefile

@@ -47,6 +47,7 @@ endif
 obj-$(CONFIG_HAVE_ARM_SCU)	+= smp_scu.o
 obj-$(CONFIG_HAVE_ARM_TWD)	+= smp_twd.o
 obj-$(CONFIG_ARM_ARCH_TIMER)	+= arch_timer.o
+obj-$(CONFIG_FUNCTION_TRACER)	+= entry-ftrace.o
 obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o insn.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o

arch/arm/kernel/entry-common.S

@@ -109,241 +109,6 @@ ENDPROC(ret_from_fork)
 #undef CALL
 #define CALL(x) .long x
 
-#ifdef CONFIG_FUNCTION_TRACER
-/*
- * When compiling with -pg, gcc inserts a call to the mcount routine at the
- * start of every function.  In mcount, apart from the function's address (in
- * lr), we need to get hold of the function's caller's address.
- *
- * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
- *
- *	bl	mcount
- *
- * These versions have the limitation that in order for the mcount routine to
- * be able to determine the function's caller's address, an APCS-style frame
- * pointer (which is set up with something like the code below) is required.
- *
- *	mov     ip, sp
- *	push    {fp, ip, lr, pc}
- *	sub     fp, ip, #4
- *
- * With EABI, these frame pointers are not available unless -mapcs-frame is
- * specified, and if building as Thumb-2, not even then.
- *
- * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
- * with call sites like:
- *
- *	push	{lr}
- *	bl	__gnu_mcount_nc
- *
- * With these compilers, frame pointers are not necessary.
- *
- * mcount can be thought of as a function called in the middle of a subroutine
- * call.  As such, it needs to be transparent for both the caller and the
- * callee: the original lr needs to be restored when leaving mcount, and no
- * registers should be clobbered.  (In the __gnu_mcount_nc implementation, we
- * clobber the ip register.  This is OK because the ARM calling convention
- * allows it to be clobbered in subroutines and doesn't use it to hold
- * parameters.)
- *
- * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
- * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
- * arch/arm/kernel/ftrace.c).
- */
-
-#ifndef CONFIG_OLD_MCOUNT
-#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
-#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
-#endif
-#endif
-
-.macro mcount_adjust_addr rd, rn
-	bic	\rd, \rn, #1		@ clear the Thumb bit if present
-	sub	\rd, \rd, #MCOUNT_INSN_SIZE
-.endm
-
-.macro __mcount suffix
-	mcount_enter
-	ldr	r0, =ftrace_trace_function
-	ldr	r2, [r0]
-	adr	r0, .Lftrace_stub
-	cmp	r0, r2
-	bne	1f
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	ldr     r1, =ftrace_graph_return
-	ldr     r2, [r1]
-	cmp     r0, r2
-	bne     ftrace_graph_caller\suffix
-
-	ldr     r1, =ftrace_graph_entry
-	ldr     r2, [r1]
-	ldr     r0, =ftrace_graph_entry_stub
-	cmp     r0, r2
-	bne     ftrace_graph_caller\suffix
-#endif
-
-	mcount_exit
-
-1: 	mcount_get_lr	r1			@ lr of instrumented func
-	mcount_adjust_addr	r0, lr		@ instrumented function
-	adr	lr, BSYM(2f)
-	mov	pc, r2
-2:	mcount_exit
-.endm
-
-.macro __ftrace_caller suffix
-	mcount_enter
-
-	mcount_get_lr	r1			@ lr of instrumented func
-	mcount_adjust_addr	r0, lr		@ instrumented function
-
-	.globl ftrace_call\suffix
-ftrace_call\suffix:
-	bl	ftrace_stub
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	.globl ftrace_graph_call\suffix
-ftrace_graph_call\suffix:
-	mov	r0, r0
-#endif
-
-	mcount_exit
-.endm
-
-.macro __ftrace_graph_caller
-	sub	r0, fp, #4		@ &lr of instrumented routine (&parent)
-#ifdef CONFIG_DYNAMIC_FTRACE
-	@ called from __ftrace_caller, saved in mcount_enter
-	ldr	r1, [sp, #16]		@ instrumented routine (func)
-	mcount_adjust_addr	r1, r1
-#else
-	@ called from __mcount, untouched in lr
-	mcount_adjust_addr	r1, lr	@ instrumented routine (func)
-#endif
-	mov	r2, fp			@ frame pointer
-	bl	prepare_ftrace_return
-	mcount_exit
-.endm
-
-#ifdef CONFIG_OLD_MCOUNT
-/*
- * mcount
- */
-
-.macro mcount_enter
-	stmdb	sp!, {r0-r3, lr}
-.endm
-
-.macro mcount_get_lr reg
-	ldr	\reg, [fp, #-4]
-.endm
-
-.macro mcount_exit
-	ldr	lr, [fp, #-4]
-	ldmia	sp!, {r0-r3, pc}
-.endm
-
-ENTRY(mcount)
-#ifdef CONFIG_DYNAMIC_FTRACE
-	stmdb	sp!, {lr}
-	ldr	lr, [fp, #-4]
-	ldmia	sp!, {pc}
-#else
-	__mcount _old
-#endif
-ENDPROC(mcount)
-
-#ifdef CONFIG_DYNAMIC_FTRACE
-ENTRY(ftrace_caller_old)
-	__ftrace_caller _old
-ENDPROC(ftrace_caller_old)
-#endif
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-ENTRY(ftrace_graph_caller_old)
-	__ftrace_graph_caller
-ENDPROC(ftrace_graph_caller_old)
-#endif
-
-.purgem mcount_enter
-.purgem mcount_get_lr
-.purgem mcount_exit
-#endif
-
-/*
- * __gnu_mcount_nc
- */
-
-.macro mcount_enter
-/*
- * This pad compensates for the push {lr} at the call site.  Note that we are
- * unable to unwind through a function which does not otherwise save its lr.
- */
- UNWIND(.pad	#4)
-	stmdb	sp!, {r0-r3, lr}
- UNWIND(.save	{r0-r3, lr})
-.endm
-
-.macro mcount_get_lr reg
-	ldr	\reg, [sp, #20]
-.endm
-
-.macro mcount_exit
-	ldmia	sp!, {r0-r3, ip, lr}
-	ret	ip
-.endm
-
-ENTRY(__gnu_mcount_nc)
-UNWIND(.fnstart)
-#ifdef CONFIG_DYNAMIC_FTRACE
-	mov	ip, lr
-	ldmia	sp!, {lr}
-	ret	ip
-#else
-	__mcount
-#endif
-UNWIND(.fnend)
-ENDPROC(__gnu_mcount_nc)
-
-#ifdef CONFIG_DYNAMIC_FTRACE
-ENTRY(ftrace_caller)
-UNWIND(.fnstart)
-	__ftrace_caller
-UNWIND(.fnend)
-ENDPROC(ftrace_caller)
-#endif
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-ENTRY(ftrace_graph_caller)
-UNWIND(.fnstart)
-	__ftrace_graph_caller
-UNWIND(.fnend)
-ENDPROC(ftrace_graph_caller)
-#endif
-
-.purgem mcount_enter
-.purgem mcount_get_lr
-.purgem mcount_exit
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	.globl return_to_handler
-return_to_handler:
-	stmdb	sp!, {r0-r3}
-	mov	r0, fp			@ frame pointer
-	bl	ftrace_return_to_handler
-	mov	lr, r0			@ r0 has real ret addr
-	ldmia	sp!, {r0-r3}
-	ret	lr
-#endif
-
-ENTRY(ftrace_stub)
-.Lftrace_stub:
-	ret	lr
-ENDPROC(ftrace_stub)
-
-#endif /* CONFIG_FUNCTION_TRACER */
-
 /*=============================================================================
  * SWI handler
  *-----------------------------------------------------------------------------

arch/arm/kernel/entry-ftrace.S

@@ -0,0 +1,243 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <asm/assembler.h>
+#include <asm/ftrace.h>
+#include <asm/unwind.h>
+
+#include "entry-header.S"
+
+/*
+ * When compiling with -pg, gcc inserts a call to the mcount routine at the
+ * start of every function.  In mcount, apart from the function's address (in
+ * lr), we need to get hold of the function's caller's address.
+ *
+ * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this:
+ *
+ *	bl	mcount
+ *
+ * These versions have the limitation that in order for the mcount routine to
+ * be able to determine the function's caller's address, an APCS-style frame
+ * pointer (which is set up with something like the code below) is required.
+ *
+ *	mov     ip, sp
+ *	push    {fp, ip, lr, pc}
+ *	sub     fp, ip, #4
+ *
+ * With EABI, these frame pointers are not available unless -mapcs-frame is
+ * specified, and if building as Thumb-2, not even then.
+ *
+ * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount,
+ * with call sites like:
+ *
+ *	push	{lr}
+ *	bl	__gnu_mcount_nc
+ *
+ * With these compilers, frame pointers are not necessary.
+ *
+ * mcount can be thought of as a function called in the middle of a subroutine
+ * call.  As such, it needs to be transparent for both the caller and the
+ * callee: the original lr needs to be restored when leaving mcount, and no
+ * registers should be clobbered.  (In the __gnu_mcount_nc implementation, we
+ * clobber the ip register.  This is OK because the ARM calling convention
+ * allows it to be clobbered in subroutines and doesn't use it to hold
+ * parameters.)
+ *
+ * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0"
+ * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see
+ * arch/arm/kernel/ftrace.c).
+ */
+
+#ifndef CONFIG_OLD_MCOUNT
+#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4))
+#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0.
+#endif
+#endif
+
+.macro mcount_adjust_addr rd, rn
+	bic	\rd, \rn, #1		@ clear the Thumb bit if present
+	sub	\rd, \rd, #MCOUNT_INSN_SIZE
+.endm
+
+.macro __mcount suffix
+	mcount_enter
+	ldr	r0, =ftrace_trace_function
+	ldr	r2, [r0]
+	adr	r0, .Lftrace_stub
+	cmp	r0, r2
+	bne	1f
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	ldr     r1, =ftrace_graph_return
+	ldr     r2, [r1]
+	cmp     r0, r2
+	bne     ftrace_graph_caller\suffix
+
+	ldr     r1, =ftrace_graph_entry
+	ldr     r2, [r1]
+	ldr     r0, =ftrace_graph_entry_stub
+	cmp     r0, r2
+	bne     ftrace_graph_caller\suffix
+#endif
+
+	mcount_exit
+
+1: 	mcount_get_lr	r1			@ lr of instrumented func
+	mcount_adjust_addr	r0, lr		@ instrumented function
+	adr	lr, BSYM(2f)
+	mov	pc, r2
+2:	mcount_exit
+.endm
+
+.macro __ftrace_caller suffix
+	mcount_enter
+
+	mcount_get_lr	r1			@ lr of instrumented func
+	mcount_adjust_addr	r0, lr		@ instrumented function
+
+	.globl ftrace_call\suffix
+ftrace_call\suffix:
+	bl	ftrace_stub
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	.globl ftrace_graph_call\suffix
+ftrace_graph_call\suffix:
+	mov	r0, r0
+#endif
+
+	mcount_exit
+.endm
+
+.macro __ftrace_graph_caller
+	sub	r0, fp, #4		@ &lr of instrumented routine (&parent)
+#ifdef CONFIG_DYNAMIC_FTRACE
+	@ called from __ftrace_caller, saved in mcount_enter
+	ldr	r1, [sp, #16]		@ instrumented routine (func)
+	mcount_adjust_addr	r1, r1
+#else
+	@ called from __mcount, untouched in lr
+	mcount_adjust_addr	r1, lr	@ instrumented routine (func)
+#endif
+	mov	r2, fp			@ frame pointer
+	bl	prepare_ftrace_return
+	mcount_exit
+.endm
+
+#ifdef CONFIG_OLD_MCOUNT
+/*
+ * mcount
+ */
+
+.macro mcount_enter
+	stmdb	sp!, {r0-r3, lr}
+.endm
+
+.macro mcount_get_lr reg
+	ldr	\reg, [fp, #-4]
+.endm
+
+.macro mcount_exit
+	ldr	lr, [fp, #-4]
+	ldmia	sp!, {r0-r3, pc}
+.endm
+
+ENTRY(mcount)
+#ifdef CONFIG_DYNAMIC_FTRACE
+	stmdb	sp!, {lr}
+	ldr	lr, [fp, #-4]
+	ldmia	sp!, {pc}
+#else
+	__mcount _old
+#endif
+ENDPROC(mcount)
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+ENTRY(ftrace_caller_old)
+	__ftrace_caller _old
+ENDPROC(ftrace_caller_old)
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ENTRY(ftrace_graph_caller_old)
+	__ftrace_graph_caller
+ENDPROC(ftrace_graph_caller_old)
+#endif
+
+.purgem mcount_enter
+.purgem mcount_get_lr
+.purgem mcount_exit
+#endif
+
+/*
+ * __gnu_mcount_nc
+ */
+
+.macro mcount_enter
+/*
+ * This pad compensates for the push {lr} at the call site.  Note that we are
+ * unable to unwind through a function which does not otherwise save its lr.
+ */
+ UNWIND(.pad	#4)
+	stmdb	sp!, {r0-r3, lr}
+ UNWIND(.save	{r0-r3, lr})
+.endm
+
+.macro mcount_get_lr reg
+	ldr	\reg, [sp, #20]
+.endm
+
+.macro mcount_exit
+	ldmia	sp!, {r0-r3, ip, lr}
+	ret	ip
+.endm
+
+ENTRY(__gnu_mcount_nc)
+UNWIND(.fnstart)
+#ifdef CONFIG_DYNAMIC_FTRACE
+	mov	ip, lr
+	ldmia	sp!, {lr}
+	ret	ip
+#else
+	__mcount
+#endif
+UNWIND(.fnend)
+ENDPROC(__gnu_mcount_nc)
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+ENTRY(ftrace_caller)
+UNWIND(.fnstart)
+	__ftrace_caller
+UNWIND(.fnend)
+ENDPROC(ftrace_caller)
+#endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ENTRY(ftrace_graph_caller)
+UNWIND(.fnstart)
+	__ftrace_graph_caller
+UNWIND(.fnend)
+ENDPROC(ftrace_graph_caller)
+#endif
+
+.purgem mcount_enter
+.purgem mcount_get_lr
+.purgem mcount_exit
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	.globl return_to_handler
+return_to_handler:
+	stmdb	sp!, {r0-r3}
+	mov	r0, fp			@ frame pointer
+	bl	ftrace_return_to_handler
+	mov	lr, r0			@ r0 has real ret addr
+	ldmia	sp!, {r0-r3}
+	ret	lr
+#endif
+
+ENTRY(ftrace_stub)
+.Lftrace_stub:
+	ret	lr
+ENDPROC(ftrace_stub)