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x86, bts, ftrace: adapt the hw-branch-tracer to the ds.c interface
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Impact: restructure code, cleanup

Remove BTS bits from the hw-branch-tracer (renamed from bts-tracer) and
use the ds interface.

Signed-off-by: Markus Metzger <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Markus Metzger authored and Ingo Molnar committed Dec 12, 2008
1 parent c272477 commit a93751c
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Showing 5 changed files with 56 additions and 129 deletions.
4 changes: 2 additions & 2 deletions kernel/trace/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -251,9 +251,9 @@ config STACK_TRACER

Say N if unsure.

config BTS_TRACER
config HW_BRANCH_TRACER
depends on HAVE_HW_BRANCH_TRACER
bool "Trace branches"
bool "Trace hw branches"
select TRACING
help
This tracer records all branches on the system in a circular
Expand Down
2 changes: 1 addition & 1 deletion kernel/trace/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
obj-$(CONFIG_BOOT_TRACER) += trace_boot.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
obj-$(CONFIG_BTS_TRACER) += trace_bts.o
obj-$(CONFIG_HW_BRANCH_TRACER) += trace_hw_branches.o
obj-$(CONFIG_POWER_TRACER) += trace_power.o

libftrace-y := ftrace.o
2 changes: 1 addition & 1 deletion kernel/trace/trace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2425,7 +2425,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)

/* Notify the tracer early; before we stop tracing. */
if (iter->trace && iter->trace->open)
iter->trace->open(iter);
iter->trace->open(iter);

/* Annotate start of buffers if we had overruns */
if (ring_buffer_overruns(iter->tr->buffer))
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14 changes: 6 additions & 8 deletions kernel/trace/trace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ enum trace_type {
TRACE_GRAPH_RET,
TRACE_GRAPH_ENT,
TRACE_USER_STACK,
TRACE_BTS,
TRACE_HW_BRANCHES,
TRACE_POWER,

__TRACE_LAST_TYPE
Expand Down Expand Up @@ -159,10 +159,10 @@ struct trace_branch {
char correct;
};

struct bts_entry {
struct hw_branch_entry {
struct trace_entry ent;
unsigned long from;
unsigned long to;
u64 from;
u64 to;
};

struct trace_power {
Expand Down Expand Up @@ -278,7 +278,7 @@ extern void __ftrace_bad_type(void);
TRACE_GRAPH_ENT); \
IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry, \
TRACE_GRAPH_RET); \
IF_ASSIGN(var, ent, struct bts_entry, TRACE_BTS);\
IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
__ftrace_bad_type(); \
} while (0)
Expand Down Expand Up @@ -414,9 +414,7 @@ void trace_function(struct trace_array *tr,

void trace_graph_return(struct ftrace_graph_ret *trace);
int trace_graph_entry(struct ftrace_graph_ent *trace);
void trace_bts(struct trace_array *tr,
unsigned long from,
unsigned long to);
void trace_hw_branch(struct trace_array *tr, u64 from, u64 to);

void tracing_start_cmdline_record(void);
void tracing_stop_cmdline_record(void);
Expand Down
163 changes: 46 additions & 117 deletions kernel/trace/trace_bts.c → kernel/trace/trace_hw_branches.c
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* BTS tracer
* h/w branch tracer for x86 based on bts
*
* Copyright (C) 2008 Markus Metzger <[email protected]>
*
Expand All @@ -25,68 +25,6 @@ static DEFINE_PER_CPU(unsigned char[SIZEOF_BTS], buffer);
#define this_buffer per_cpu(buffer, smp_processor_id())


/*
* Information to interpret a BTS record.
* This will go into an in-kernel BTS interface.
*/
static unsigned char sizeof_field;
static unsigned long debugctl_mask;

#define sizeof_bts (3 * sizeof_field)

static void bts_trace_cpuinit(struct cpuinfo_x86 *c)
{
switch (c->x86) {
case 0x6:
switch (c->x86_model) {
case 0x0 ... 0xC:
break;
case 0xD:
case 0xE: /* Pentium M */
sizeof_field = sizeof(long);
debugctl_mask = (1<<6)|(1<<7);
break;
default:
sizeof_field = 8;
debugctl_mask = (1<<6)|(1<<7);
break;
}
break;
case 0xF:
switch (c->x86_model) {
case 0x0:
case 0x1:
case 0x2: /* Netburst */
sizeof_field = sizeof(long);
debugctl_mask = (1<<2)|(1<<3);
break;
default:
/* sorry, don't know about them */
break;
}
break;
default:
/* sorry, don't know about them */
break;
}
}

static inline void bts_enable(void)
{
unsigned long debugctl;

rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl | debugctl_mask);
}

static inline void bts_disable(void)
{
unsigned long debugctl;

rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl & ~debugctl_mask);
}

static void bts_trace_reset(struct trace_array *tr)
{
int cpu;
Expand All @@ -99,15 +37,17 @@ static void bts_trace_reset(struct trace_array *tr)

static void bts_trace_start_cpu(void *arg)
{
if (this_tracer)
ds_release_bts(this_tracer);

this_tracer =
ds_request_bts(/* task = */ NULL, this_buffer, SIZEOF_BTS,
/* ovfl = */ NULL, /* th = */ (size_t)-1);
/* ovfl = */ NULL, /* th = */ (size_t)-1,
BTS_KERNEL);
if (IS_ERR(this_tracer)) {
this_tracer = NULL;
return;
}

bts_enable();
}

static void bts_trace_start(struct trace_array *tr)
Expand All @@ -123,8 +63,6 @@ static void bts_trace_start(struct trace_array *tr)
static void bts_trace_stop_cpu(void *arg)
{
if (this_tracer) {
bts_disable();

ds_release_bts(this_tracer);
this_tracer = NULL;
}
Expand All @@ -140,7 +78,6 @@ static void bts_trace_stop(struct trace_array *tr)

static int bts_trace_init(struct trace_array *tr)
{
bts_trace_cpuinit(&boot_cpu_data);
bts_trace_reset(tr);
bts_trace_start(tr);

Expand All @@ -149,104 +86,96 @@ static int bts_trace_init(struct trace_array *tr)

static void bts_trace_print_header(struct seq_file *m)
{
#ifdef __i386__
seq_puts(m, "# CPU# FROM TO FUNCTION\n");
seq_puts(m, "# | | | |\n");
#else
seq_puts(m,
"# CPU# FROM TO FUNCTION\n");
seq_puts(m,
"# | | | |\n");
#endif
}

static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
{
struct trace_entry *entry = iter->ent;
struct trace_seq *seq = &iter->seq;
struct bts_entry *it;
struct hw_branch_entry *it;

trace_assign_type(it, entry);

if (entry->type == TRACE_BTS) {
int ret;
#ifdef CONFIG_KALLSYMS
char function[KSYM_SYMBOL_LEN];
sprint_symbol(function, it->from);
#else
char *function = "<unknown>";
#endif

ret = trace_seq_printf(seq, "%4d 0x%lx -> 0x%lx [%s]\n",
entry->cpu, it->from, it->to, function);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;;
return TRACE_TYPE_HANDLED;
if (entry->type == TRACE_HW_BRANCHES) {
if (trace_seq_printf(seq, "%4d ", entry->cpu) &&
trace_seq_printf(seq, "0x%016llx -> 0x%016llx ",
it->from, it->to) &&
(!it->from ||
seq_print_ip_sym(seq, it->from, /* sym_flags = */ 0)) &&
trace_seq_printf(seq, "\n"))
return TRACE_TYPE_HANDLED;
return TRACE_TYPE_PARTIAL_LINE;;
}
return TRACE_TYPE_UNHANDLED;
}

void trace_bts(struct trace_array *tr, unsigned long from, unsigned long to)
void trace_hw_branch(struct trace_array *tr, u64 from, u64 to)
{
struct ring_buffer_event *event;
struct bts_entry *entry;
struct hw_branch_entry *entry;
unsigned long irq;

event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq);
if (!event)
return;
entry = ring_buffer_event_data(event);
tracing_generic_entry_update(&entry->ent, 0, from);
entry->ent.type = TRACE_BTS;
entry->ent.type = TRACE_HW_BRANCHES;
entry->ent.cpu = smp_processor_id();
entry->from = from;
entry->to = to;
ring_buffer_unlock_commit(tr->buffer, event, irq);
}

static void trace_bts_at(struct trace_array *tr, size_t index)
static void trace_bts_at(struct trace_array *tr,
const struct bts_trace *trace, void *at)
{
const void *raw = NULL;
unsigned long from, to;
int err;
struct bts_struct bts;
int err = 0;

err = ds_access_bts(this_tracer, index, &raw);
if (err < 0)
WARN_ON_ONCE(!trace->read);
if (!trace->read)
return;

from = *(const unsigned long *)raw;
to = *(const unsigned long *)((const char *)raw + sizeof_field);
err = trace->read(this_tracer, at, &bts);
if (err < 0)
return;

trace_bts(tr, from, to);
switch (bts.qualifier) {
case BTS_BRANCH:
trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to);
break;
}
}

static void trace_bts_cpu(void *arg)
{
struct trace_array *tr = (struct trace_array *) arg;
size_t index = 0, end = 0, i;
int err;
const struct bts_trace *trace;
unsigned char *at;

if (!this_tracer)
return;

bts_disable();

err = ds_get_bts_index(this_tracer, &index);
if (err < 0)
goto out;

err = ds_get_bts_end(this_tracer, &end);
if (err < 0)
ds_suspend_bts(this_tracer);
trace = ds_read_bts(this_tracer);
if (!trace)
goto out;

for (i = index; i < end; i++)
trace_bts_at(tr, i);
for (at = trace->ds.top; (void *)at < trace->ds.end;
at += trace->ds.size)
trace_bts_at(tr, trace, at);

for (i = 0; i < index; i++)
trace_bts_at(tr, i);
for (at = trace->ds.begin; (void *)at < trace->ds.top;
at += trace->ds.size)
trace_bts_at(tr, trace, at);

out:
bts_enable();
ds_resume_bts(this_tracer);
}

static void trace_bts_prepare(struct trace_iterator *iter)
Expand All @@ -259,7 +188,7 @@ static void trace_bts_prepare(struct trace_iterator *iter)

struct tracer bts_tracer __read_mostly =
{
.name = "bts",
.name = "hw-branch-tracer",
.init = bts_trace_init,
.reset = bts_trace_stop,
.print_header = bts_trace_print_header,
Expand Down

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