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tracing/kprobes: Cleanup kprobe tracer code.
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Simplify trace_probe to remove a union, and remove some redundant
wrappers.
And also, cleanup create_trace_probe() function.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090910235322.22412.52525.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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Masami Hiramatsu authored and Frederic Weisbecker committed Sep 11, 2009
1 parent 2fba0c8 commit 4a846b4
Showing 1 changed file with 34 additions and 47 deletions.
81 changes: 34 additions & 47 deletions kernel/trace/trace_kprobe.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -180,10 +180,7 @@ static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)

struct trace_probe {
struct list_head list;
union {
struct kprobe kp;
struct kretprobe rp;
};
struct kretprobe rp; /* Use rp.kp for kprobe use */
unsigned long nhit;
const char *symbol; /* symbol name */
struct ftrace_event_call call;
Expand All @@ -202,24 +199,14 @@ static int kretprobe_trace_func(struct kretprobe_instance *ri,

static __kprobes int probe_is_return(struct trace_probe *tp)
{
return (tp->rp.handler == kretprobe_trace_func);
return tp->rp.handler != NULL;
}

static __kprobes const char *probe_symbol(struct trace_probe *tp)
{
return tp->symbol ? tp->symbol : "unknown";
}

static __kprobes unsigned int probe_offset(struct trace_probe *tp)
{
return (probe_is_return(tp)) ? tp->rp.kp.offset : tp->kp.offset;
}

static __kprobes void *probe_address(struct trace_probe *tp)
{
return (probe_is_return(tp)) ? tp->rp.kp.addr : tp->kp.addr;
}

static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
{
int ret = -EINVAL;
Expand Down Expand Up @@ -269,8 +256,14 @@ static void unregister_probe_event(struct trace_probe *tp);
static DEFINE_MUTEX(probe_lock);
static LIST_HEAD(probe_list);

static struct trace_probe *alloc_trace_probe(const char *symbol,
const char *event, int nargs)
/*
* Allocate new trace_probe and initialize it (including kprobes).
*/
static struct trace_probe *alloc_trace_probe(const char *event,
void *addr,
const char *symbol,
unsigned long offs,
int nargs, int is_return)
{
struct trace_probe *tp;

Expand All @@ -282,7 +275,16 @@ static struct trace_probe *alloc_trace_probe(const char *symbol,
tp->symbol = kstrdup(symbol, GFP_KERNEL);
if (!tp->symbol)
goto error;
}
tp->rp.kp.symbol_name = tp->symbol;
tp->rp.kp.offset = offs;
} else
tp->rp.kp.addr = addr;

if (is_return)
tp->rp.handler = kretprobe_trace_func;
else
tp->rp.kp.pre_handler = kprobe_trace_func;

if (!event)
goto error;
tp->call.name = kstrdup(event, GFP_KERNEL);
Expand Down Expand Up @@ -327,7 +329,7 @@ static void __unregister_trace_probe(struct trace_probe *tp)
if (probe_is_return(tp))
unregister_kretprobe(&tp->rp);
else
unregister_kprobe(&tp->kp);
unregister_kprobe(&tp->rp.kp);
}

/* Unregister a trace_probe and probe_event: call with locking probe_lock */
Expand All @@ -349,14 +351,14 @@ static int register_trace_probe(struct trace_probe *tp)
if (probe_is_return(tp))
ret = register_kretprobe(&tp->rp);
else
ret = register_kprobe(&tp->kp);
ret = register_kprobe(&tp->rp.kp);

if (ret) {
pr_warning("Could not insert probe(%d)\n", ret);
if (ret == -EILSEQ) {
pr_warning("Probing address(0x%p) is not an "
"instruction boundary.\n",
probe_address(tp));
tp->rp.kp.addr);
ret = -EINVAL;
}
goto end;
Expand Down Expand Up @@ -530,12 +532,12 @@ static int create_trace_probe(int argc, char **argv)
* +|-offs(ARG) : fetch memory at ARG +|- offs address.
*/
struct trace_probe *tp;
struct kprobe *kp;
int i, ret = 0;
int is_return = 0;
char *symbol = NULL, *event = NULL;
unsigned long offset = 0;
void *addr = NULL;
char buf[MAX_EVENT_NAME_LEN];

if (argc < 2)
return -EINVAL;
Expand Down Expand Up @@ -577,33 +579,18 @@ static int create_trace_probe(int argc, char **argv)
/* setup a probe */
if (!event) {
/* Make a new event name */
char buf[MAX_EVENT_NAME_LEN];
if (symbol)
snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
is_return ? 'r' : 'p', symbol, offset);
else
snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
is_return ? 'r' : 'p', addr);
tp = alloc_trace_probe(symbol, buf, argc);
} else
tp = alloc_trace_probe(symbol, event, argc);
event = buf;
}
tp = alloc_trace_probe(event, addr, symbol, offset, argc, is_return);
if (IS_ERR(tp))
return PTR_ERR(tp);

if (is_return) {
kp = &tp->rp.kp;
tp->rp.handler = kretprobe_trace_func;
} else {
kp = &tp->kp;
tp->kp.pre_handler = kprobe_trace_func;
}

if (tp->symbol) {
kp->symbol_name = tp->symbol;
kp->offset = (unsigned int)offset;
} else
kp->addr = addr;

/* parse arguments */
ret = 0;
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
Expand Down Expand Up @@ -670,9 +657,9 @@ static int probes_seq_show(struct seq_file *m, void *v)
seq_printf(m, ":%s", tp->call.name);

if (tp->symbol)
seq_printf(m, " %s+%u", probe_symbol(tp), probe_offset(tp));
seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
else
seq_printf(m, " 0x%p", probe_address(tp));
seq_printf(m, " 0x%p", tp->rp.kp.addr);

for (i = 0; i < tp->nr_args; i++) {
ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i]);
Expand Down Expand Up @@ -783,7 +770,7 @@ static int probes_profile_seq_show(struct seq_file *m, void *v)
struct trace_probe *tp = v;

seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
probe_is_return(tp) ? tp->rp.kp.nmissed : tp->kp.nmissed);
tp->rp.kp.nmissed);

return 0;
}
Expand Down Expand Up @@ -811,7 +798,7 @@ static const struct file_operations kprobe_profile_ops = {
/* Kprobe handler */
static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
{
struct trace_probe *tp = container_of(kp, struct trace_probe, kp);
struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
struct kprobe_trace_entry *entry;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
Expand Down Expand Up @@ -866,7 +853,7 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,

entry = ring_buffer_event_data(event);
entry->nargs = tp->nr_args;
entry->func = (unsigned long)probe_address(tp);
entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i], regs);
Expand Down Expand Up @@ -945,7 +932,7 @@ static int probe_event_enable(struct ftrace_event_call *call)
if (probe_is_return(tp))
return enable_kretprobe(&tp->rp);
else
return enable_kprobe(&tp->kp);
return enable_kprobe(&tp->rp.kp);
}

static void probe_event_disable(struct ftrace_event_call *call)
Expand All @@ -955,7 +942,7 @@ static void probe_event_disable(struct ftrace_event_call *call)
if (probe_is_return(tp))
disable_kretprobe(&tp->rp);
else
disable_kprobe(&tp->kp);
disable_kprobe(&tp->rp.kp);
}

static int probe_event_raw_init(struct ftrace_event_call *event_call)
Expand Down

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