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Commit f5074429 authored by Mike Frysinger's avatar Mike Frysinger
Browse files

Blackfin: add support for dynamic ftrace 



Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
parent 67df6cc6

arch/blackfin/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ config BLACKFIN 
	def_bool y

	select HAVE_ARCH_KGDB

	select HAVE_ARCH_TRACEHOOK

	select HAVE_DYNAMIC_FTRACE

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER

	select HAVE_FUNCTION_TRACE_MCOUNT_TEST

arch/blackfin/include/asm/ftrace.h

+16 −0
Original line number Diff line number Diff line
@@ -12,6 +12,22 @@ 


#ifndef __ASSEMBLY__



#ifdef CONFIG_DYNAMIC_FTRACE



extern void _mcount(void);

#define MCOUNT_ADDR ((unsigned long)_mcount)



static inline unsigned long ftrace_call_adjust(unsigned long addr)

{

	return addr;

}



struct dyn_arch_ftrace {

	/* No extra data needed for Blackfin */

};



#endif



#ifdef CONFIG_FRAME_POINTER

#include <linux/mm.h>

arch/blackfin/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ else 
    obj-y += time.o

endif



obj-$(CONFIG_DYNAMIC_FTRACE)         += ftrace.o

obj-$(CONFIG_FUNCTION_TRACER)        += ftrace-entry.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER)  += ftrace.o

CFLAGS_REMOVE_ftrace.o = -pg

arch/blackfin/kernel/ftrace-entry.S

+77 −8
Original line number Diff line number Diff line
@@ -10,6 +10,18 @@ 


.text



#ifdef CONFIG_DYNAMIC_FTRACE



/* Simple stub so we can boot the kernel until runtime patching has

 * disabled all calls to this.  Then it'll be unused.

 */

ENTRY(__mcount)

# if ANOMALY_05000371

	nop; nop; nop; nop;

# endif

	rts;

ENDPROC(__mcount)



/* GCC will have called us before setting up the function prologue, so we

 * can clobber the normal scratch registers, but we need to make sure to

 * save/restore the registers used for argument passing (R0-R2) in case
@@ -20,6 +32,56 @@ 
 * function.  And since GCC pushed the previous RETS for us, the previous

 * function will be waiting there.  mmmm pie.

 */

ENTRY(_ftrace_caller)

# ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST

	/* optional micro optimization: return if stopped */

	p1.l = _function_trace_stop;

	p1.h = _function_trace_stop;

	r3 = [p1];

	cc = r3 == 0;

	if ! cc jump _ftrace_stub (bp);

# endif



	/* save first/second/third function arg and the return register */

	[--sp] = r2;

	[--sp] = r0;

	[--sp] = r1;

	[--sp] = rets;



	/* function_trace_call(unsigned long ip, unsigned long parent_ip):

	 *  ip: this point was called by ...

	 *  parent_ip: ... this function

	 * the ip itself will need adjusting for the mcount call

	 */

	r0 = rets;

	r1 = [sp + 16];	/* skip the 4 local regs on stack */

	r0 += -MCOUNT_INSN_SIZE;



.globl _ftrace_call

_ftrace_call:

	call _ftrace_stub



# ifdef CONFIG_FUNCTION_GRAPH_TRACER

.globl _ftrace_graph_call

_ftrace_graph_call:

	nop;	/* jump _ftrace_graph_caller; */

# endif



	/* restore state and get out of dodge */

.Lfinish_trace:

	rets = [sp++];

	r1 = [sp++];

	r0 = [sp++];

	r2 = [sp++];



.globl _ftrace_stub

_ftrace_stub:

	rts;

ENDPROC(_ftrace_caller)



#else



/* See documentation for _ftrace_caller */

ENTRY(__mcount)

# ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST

	/* optional micro optimization: return if stopped */
@@ -103,6 +165,8 @@ _ftrace_stub: 
	rts;

ENDPROC(__mcount)



#endif



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

/* The prepare_ftrace_return() function is similar to the trace function

 * except it takes a pointer to the location of the frompc.  This is so
@@ -110,6 +174,7 @@ ENDPROC(__mcount) 
 * purposes.

 */

ENTRY(_ftrace_graph_caller)

# ifndef CONFIG_DYNAMIC_FTRACE

	/* save first/second function arg and the return register */

	[--sp] = r0;

	[--sp] = r1;
@@ -118,6 +183,10 @@ ENTRY(_ftrace_graph_caller) 
	/* prepare_ftrace_return(parent, self_addr, frame_pointer) */

	r0 = sp;	/* unsigned long *parent */

	r1 = rets;	/* unsigned long self_addr */

# else

	r0 = sp;	/* unsigned long *parent */

	r1 = [sp];	/* unsigned long self_addr */

# endif

# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST

	r2 = fp;	/* unsigned long frame_pointer */

# endif

arch/blackfin/kernel/ftrace.c

+85 −1
Original line number Diff line number Diff line 
/*

 * ftrace graph code

 *

 * Copyright (C) 2009 Analog Devices Inc.

 * Copyright (C) 2009-2010 Analog Devices Inc.

 * Licensed under the GPL-2 or later.

 */



#include <linux/ftrace.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/uaccess.h>

#include <asm/atomic.h>

#include <asm/cacheflush.h>



#ifdef CONFIG_DYNAMIC_FTRACE



static const unsigned char mnop[] = {

	0x03, 0xc0, 0x00, 0x18, /* MNOP; */

	0x03, 0xc0, 0x00, 0x18, /* MNOP; */

};



static void bfin_make_pcrel24(unsigned char *insn, unsigned long src,

                              unsigned long dst)

{

	uint32_t pcrel = (dst - src) >> 1;

	insn[0] = pcrel >> 16;

	insn[1] = 0xe3;

	insn[2] = pcrel;

	insn[3] = pcrel >> 8;

}

#define bfin_make_pcrel24(insn, src, dst) bfin_make_pcrel24(insn, src, (unsigned long)(dst))



static int ftrace_modify_code(unsigned long ip, const unsigned char *code,

                              unsigned long len)

{

	int ret = probe_kernel_write((void *)ip, (void *)code, len);

	flush_icache_range(ip, ip + len);

	return ret;

}



int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,

                    unsigned long addr)

{

	/* Turn the mcount call site into two MNOPs as those are 32bit insns */

	return ftrace_modify_code(rec->ip, mnop, sizeof(mnop));

}



int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

{

	/* Restore the mcount call site */

	unsigned char call[8];

	call[0] = 0x67; /* [--SP] = RETS; */

	call[1] = 0x01;

	bfin_make_pcrel24(&call[2], rec->ip + 2, addr);

	call[6] = 0x27; /* RETS = [SP++]; */

	call[7] = 0x01;

	return ftrace_modify_code(rec->ip, call, sizeof(call));

}



int ftrace_update_ftrace_func(ftrace_func_t func)

{

	unsigned char call[4];

	unsigned long ip = (unsigned long)&ftrace_call;

	bfin_make_pcrel24(call, ip, func);

	return ftrace_modify_code(ip, call, sizeof(call));

}



int __init ftrace_dyn_arch_init(void *data)

{

	/* return value is done indirectly via data */

	*(unsigned long *)data = 0;



	return 0;

}



#endif



#ifdef CONFIG_FUNCTION_GRAPH_TRACER



# ifdef CONFIG_DYNAMIC_FTRACE



extern void ftrace_graph_call(void);



int ftrace_enable_ftrace_graph_caller(void)

{

	unsigned long ip = (unsigned long)&ftrace_graph_call;

	uint16_t jump_pcrel12 = ((unsigned long)&ftrace_graph_caller - ip) >> 1;

	jump_pcrel12 |= 0x2000;

	return ftrace_modify_code(ip, (void *)&jump_pcrel12, sizeof(jump_pcrel12));

}



int ftrace_disable_ftrace_graph_caller(void)

{

	return ftrace_modify_code((unsigned long)&ftrace_graph_call, empty_zero_page, 2);

}



# endif



/*

 * Hook the return address and push it in the stack of return addrs

 * in current thread info.