Commit 82112379 authored by Russell King's avatar Russell King
Browse files

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: default avatarFelipe Balbi <balbi@ti.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 719c9d14

arch/arm/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

+0 −235
Original line number Diff line number Diff line
@@ -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 → 100644
+243 −0
Original line number Diff line number Diff line 
/*

 * 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)

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