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Message-Id: <1385533203-10014-18-git-send-email-namhyung@kernel.org>
Date: Wed, 27 Nov 2013 15:20:03 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Steven Rostedt <rostedt@...dmis.org>,
Oleg Nesterov <oleg@...hat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Hyeoncheol Lee <cheol.lee@....com>,
Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
"zhangwei(Jovi)" <jovi.zhangwei@...wei.com>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
Hemant Kumar <hkshaw@...ux.vnet.ibm.com>,
LKML <linux-kernel@...r.kernel.org>,
Namhyung Kim <namhyung.kim@....com>
Subject: [PATCH/RFC 17/17] tracing/uprobes: Add @+file_offset fetch method
From: Namhyung Kim <namhyung.kim@....com>
Enable to fetch data from a file offset. Currently it only supports
fetching from same binary uprobe set. It'll translate the file offset
to a proper virtual address in the process.
The syntax is "@+OFFSET" as it does similar to normal memory fetching
(@ADDR) which does no address translation.
To do it, change fifth argument to receive 'void *priv' and make it
set only for uprobes so that we can determine the arg is for kprobes
or uprobes easily.
Suggested-by: Oleg Nesterov <oleg@...hat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@...wei.com>
Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
Documentation/trace/uprobetracer.txt | 1 +
kernel/trace/trace_kprobe.c | 10 +++++++++-
kernel/trace/trace_probe.c | 32 +++++++++++++++++++++++++++-----
kernel/trace/trace_probe.h | 9 ++++++++-
kernel/trace/trace_uprobe.c | 36 +++++++++++++++++++++++++++++++++++-
5 files changed, 80 insertions(+), 8 deletions(-)
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt
index 6e5cff263e2b..f1cf9a34ad9d 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.txt
@@ -32,6 +32,7 @@ Synopsis of uprobe_tracer
FETCHARGS : Arguments. Each probe can have up to 128 args.
%REG : Fetch register REG
@ADDR : Fetch memory at ADDR (ADDR should be in userspace)
+ @+OFFSET : Fetch memory at OFFSET (OFFSET from same file as PATH)
$stackN : Fetch Nth entry of stack (N >= 0)
$stack : Fetch stack address.
$retval : Fetch return value.(*)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 5c4f72d45b97..300fd0f8b2a9 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -239,6 +239,14 @@ DEFINE_BASIC_FETCH_FUNCS(symbol)
DEFINE_FETCH_symbol(string)
DEFINE_FETCH_symbol(string_size)
+/* kprobes don't support file_offset fetch methods */
+#define fetch_file_offset_u8 NULL
+#define fetch_file_offset_u16 NULL
+#define fetch_file_offset_u32 NULL
+#define fetch_file_offset_u64 NULL
+#define fetch_file_offset_string NULL
+#define fetch_file_offset_string_size NULL
+
/* Fetch type information table */
const struct fetch_type kprobes_fetch_type_table[] = {
/* Special types */
@@ -758,7 +766,7 @@ static int create_trace_kprobe(int argc, char **argv)
/* Parse fetch argument */
ret = traceprobe_parse_probe_arg(arg, &tp->p.size, parg,
- is_return, true);
+ is_return, NULL);
if (ret) {
pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
goto error;
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 1be603d45811..bd16aed615b2 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -348,13 +348,14 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
/* Recursive argument parser */
static int parse_probe_arg(char *arg, const struct fetch_type *t,
- struct fetch_param *f, bool is_return, bool is_kprobe)
+ struct fetch_param *f, bool is_return, void *priv)
{
const struct fetch_type *ftbl;
unsigned long param;
long offset;
char *tmp;
int ret = 0;
+ bool is_kprobe = (priv == NULL);
ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
BUG_ON(ftbl == NULL);
@@ -373,7 +374,7 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
}
break;
- case '@': /* memory or symbol */
+ case '@': /* memory, file-offset or symbol */
if (isdigit(arg[1])) {
ret = kstrtoul(arg + 1, 0, ¶m);
if (ret)
@@ -381,6 +382,26 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
f->fn = t->fetch[FETCH_MTD_memory];
f->data = (void *)param;
+ } else if (arg[1] == '+') {
+ struct file_offset_fetch_param *foprm;
+
+ /* kprobes don't support file offsets */
+ if (is_kprobe)
+ return -EINVAL;
+
+ ret = kstrtol(arg + 2, 0, &offset);
+ if (ret)
+ break;
+
+ foprm = kzalloc(sizeof(*foprm), GFP_KERNEL);
+ if (!foprm)
+ return -ENOMEM;
+
+ foprm->tu = priv;
+ foprm->offset = offset;
+
+ f->fn = t->fetch[FETCH_MTD_file_offset];
+ f->data = foprm;
} else {
/* uprobes don't support symbols */
if (!is_kprobe)
@@ -428,7 +449,7 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
dprm->fetch_size = get_fetch_size_function(t,
dprm->fetch, ftbl);
ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
- is_kprobe);
+ priv);
if (ret)
kfree(dprm);
else {
@@ -486,11 +507,12 @@ static int __parse_bitfield_probe_arg(const char *bf,
/* String length checking wrapper */
int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
- struct probe_arg *parg, bool is_return, bool is_kprobe)
+ struct probe_arg *parg, bool is_return, void *priv)
{
const struct fetch_type *ftbl;
const char *t;
int ret;
+ bool is_kprobe = (priv == NULL);
ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
BUG_ON(ftbl == NULL);
@@ -516,7 +538,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
}
parg->offset = *size;
*size += parg->type->size;
- ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
+ ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, priv);
if (ret >= 0 && t != NULL)
ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index c2f9adbfab3f..ea0c80d37c31 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -106,6 +106,7 @@ enum {
FETCH_MTD_symbol,
FETCH_MTD_deref,
FETCH_MTD_bitfield,
+ FETCH_MTD_file_offset,
FETCH_MTD_END,
};
@@ -217,6 +218,7 @@ ASSIGN_FETCH_FUNC(memory, ftype), \
ASSIGN_FETCH_FUNC(symbol, ftype), \
ASSIGN_FETCH_FUNC(deref, ftype), \
ASSIGN_FETCH_FUNC(bitfield, ftype), \
+ASSIGN_FETCH_FUNC(file_offset, ftype), \
} \
}
@@ -291,6 +293,11 @@ static inline __kprobes void call_fetch(struct fetch_param *fprm,
return fprm->fn(regs, fprm->data, dest);
}
+struct file_offset_fetch_param {
+ unsigned long offset;
+ struct trace_uprobe *tu;
+};
+
/* Check the name is good for event/group/fields */
static inline int is_good_name(const char *name)
{
@@ -304,7 +311,7 @@ static inline int is_good_name(const char *name)
}
extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
- struct probe_arg *parg, bool is_return, bool is_kprobe);
+ struct probe_arg *parg, bool is_return, void *priv);
extern int traceprobe_conflict_field_name(const char *name,
struct probe_arg *args, int narg);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index c037477d1c1a..fb1b81e2603a 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -175,6 +175,26 @@ static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
#define fetch_symbol_string NULL
#define fetch_symbol_string_size NULL
+static unsigned long translate_user_vaddr(struct file_offset_fetch_param *foprm)
+{
+ unsigned long base_addr;
+
+ base_addr = current->utask->vaddr - foprm->tu->offset;
+ return base_addr + foprm->offset;
+}
+
+#define DEFINE_FETCH_file_offset(type) \
+static __kprobes void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,\
+ void *data, void *dest) \
+{ \
+ void *vaddr = (void *)translate_user_vaddr(data); \
+ \
+ FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \
+}
+DEFINE_BASIC_FETCH_FUNCS(file_offset)
+DEFINE_FETCH_file_offset(string)
+DEFINE_FETCH_file_offset(string_size)
+
/* Fetch type information table */
const struct fetch_type uprobes_fetch_type_table[] = {
/* Special types */
@@ -512,7 +532,7 @@ static int create_trace_uprobe(int argc, char **argv)
/* Parse fetch argument */
ret = traceprobe_parse_probe_arg(arg, &tu->p.size, parg,
- is_return, false);
+ is_return, tu);
if (ret) {
pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
goto error;
@@ -1104,11 +1124,18 @@ int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
{
struct trace_uprobe *tu;
+ struct uprobe_task *utask;
int ret = 0;
tu = container_of(con, struct trace_uprobe, consumer);
tu->nhit++;
+ utask = current->utask;
+ if (utask == NULL)
+ return UPROBE_HANDLER_REMOVE;
+
+ utask->vaddr = instruction_pointer(regs);
+
if (tu->p.flags & TP_FLAG_TRACE)
ret |= uprobe_trace_func(tu, regs);
@@ -1123,9 +1150,16 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con,
unsigned long func, struct pt_regs *regs)
{
struct trace_uprobe *tu;
+ struct uprobe_task *utask;
tu = container_of(con, struct trace_uprobe, consumer);
+ utask = current->utask;
+ if (utask == NULL)
+ return UPROBE_HANDLER_REMOVE;
+
+ utask->vaddr = func;
+
if (tu->p.flags & TP_FLAG_TRACE)
uretprobe_trace_func(tu, func, regs);
--
1.7.11.7
--
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