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Blackfin: add support for dynamic ftrace

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Signed-off-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Mike Frysinger 2010-07-21 09:13:02 -04:00
parent 67df6cc665
commit f507442962
5 changed files with 182 additions and 10 deletions
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2
arch/blackfin/Kconfig
View file

@ -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

16
arch/blackfin/include/asm/ftrace.h
View file

@ -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>

1
arch/blackfin/kernel/Makefile
View file

@ -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

87
arch/blackfin/kernel/ftrace-entry.S
View file

@ -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
@ -20,15 +32,65 @@
* function. And since GCC pushed the previous RETS for us, the previous
* function will be waiting there. mmmm pie.
*/
ENTRY(__mcount)
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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
# 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 */
p1.l = _function_trace_stop;
p1.h = _function_trace_stop;
r3 = [p1];
cc = r3 == 0;
if ! cc jump _ftrace_stub (bp);
# endif
/* save third function arg early so we can do testing below */
[--sp] = r2;
@ -44,7 +106,7 @@ ENTRY(__mcount)
cc = r2 == r3;
if ! cc jump .Ldo_trace;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
# ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* if the ftrace_graph_return function pointer is not set to
* the ftrace_stub entry, call prepare_ftrace_return().
*/
@ -64,7 +126,7 @@ ENTRY(__mcount)
r3 = [p0];
cc = r2 == r3;
if ! cc jump _ftrace_graph_caller;
#endif
# endif
r2 = [sp++];
rts;
@ -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;
@ -118,9 +183,13 @@ ENTRY(_ftrace_graph_caller)
/* prepare_ftrace_return(parent, self_addr, frame_pointer) */
r0 = sp; /* unsigned long *parent */
r1 = rets; /* unsigned long self_addr */
#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
# 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
# endif
r0 += 16; /* skip the 4 local regs on stack */
r1 += -MCOUNT_INSN_SIZE;
call _prepare_ftrace_return;
@ -139,9 +208,9 @@ ENTRY(_return_to_handler)
[--sp] = r1;
/* get original return address */
#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
# ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
r0 = fp; /* Blackfin is sane, so omit this */
#endif
# endif
call _ftrace_return_to_handler;
rets = r0;

86
arch/blackfin/kernel/ftrace.c
View file

@ -1,17 +1,101 @@
/*
* 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.