[PATCH 26/35] ftrace: kprobe: uprobe: Add x8/x16/x32/x64 for hexadecimal types

From: Arnaldo Carvalho de Melo
Date: Tue Aug 23 2016 - 17:05:49 EST

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From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Add x8/x16/x32/x64 for hexadecimal type casting to kprobe/uprobe event
tracer.

These type casts can be used for integer arguments for explicitly
showing them in hexadecimal digits in formatted text.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Hemant Kumar <hemant@xxxxxxxxxxxxxxxxxx>
Cc: Naohiro Aota <naohiro.aota@xxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: 147151067029.12957.11591314629326414783.stgit@devbox">http://lkml.kernel.org/r/147151067029.12957.11591314629326414783.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
Documentation/trace/kprobetrace.txt | 4 ++--
Documentation/trace/uprobetracer.txt | 4 ++--
kernel/trace/trace_kprobe.c | 4 ++++
kernel/trace/trace_probe.c | 30 +++++++++++++++++-------------
kernel/trace/trace_probe.h | 9 +++++++++
kernel/trace/trace_uprobe.c | 4 ++++
tools/perf/Documentation/perf-probe.txt | 4 ++--
7 files changed, 40 insertions(+), 19 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index ea52ec1f8484..9109c8e8a5a1 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -44,8 +44,8 @@ Synopsis of kprobe_events
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
- (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
- are supported.
+ (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
+ (x8/x16/x32/x64), "string" and bitfield are supported.

(*) only for return probe.
(**) this is useful for fetching a field of data structures.
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt
index 72d1cd4f7bf3..7e6d28c54b75 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.txt
@@ -40,8 +40,8 @@ Synopsis of uprobe_tracer
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
- (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
- are supported.
+ (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
+ (x8/x16/x32/x64), "string" and bitfield are supported.

(*) only for return probe.
(**) this is useful for fetching a field of data structures.
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9aedb0b06683..eb6c9f1d3a93 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -253,6 +253,10 @@ static const struct fetch_type kprobes_fetch_type_table[] = {
ASSIGN_FETCH_TYPE(s16, u16, 1),
ASSIGN_FETCH_TYPE(s32, u32, 1),
ASSIGN_FETCH_TYPE(s64, u64, 1),
+ ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
+ ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
+ ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
+ ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),

ASSIGN_FETCH_TYPE_END
};
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 74e80a582c28..725af9dcbdff 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -36,24 +36,28 @@ const char *reserved_field_names[] = {
};

/* Printing in basic type function template */
-#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt) \
-int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
+#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
+int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, const char *name, \
void *data, void *ent) \
{ \
trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
return !trace_seq_has_overflowed(s); \
} \
-const char PRINT_TYPE_FMT_NAME(type)[] = fmt; \
-NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
-
-DEFINE_BASIC_PRINT_TYPE_FUNC(u8 , "0x%x")
-DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "0x%x")
-DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "0x%x")
-DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "0x%Lx")
-DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d")
-DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d")
-DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%d")
-DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%Ld")
+const char PRINT_TYPE_FMT_NAME(tname)[] = fmt; \
+NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(tname));
+
+DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "0x%Lx")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
+DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
+DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")

/* Print type function for string type */
int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 45400ca5ded1..f0c470a10edd 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -149,6 +149,11 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x8);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
+DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
+
DECLARE_BASIC_PRINT_TYPE_FUNC(string);

#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
@@ -234,6 +239,10 @@ ASSIGN_FETCH_FUNC(file_offset, ftype), \
#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
__ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)

+/* If ptype is an alias of atype, use this macro (show atype in format) */
+#define ASSIGN_FETCH_TYPE_ALIAS(ptype, atype, ftype, sign) \
+ __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #atype)
+
#define ASSIGN_FETCH_TYPE_END {}

#define FETCH_TYPE_STRING 0
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index c53485441c88..7a687320f867 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -211,6 +211,10 @@ static const struct fetch_type uprobes_fetch_type_table[] = {
ASSIGN_FETCH_TYPE(s16, u16, 1),
ASSIGN_FETCH_TYPE(s32, u32, 1),
ASSIGN_FETCH_TYPE(s64, u64, 1),
+ ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
+ ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
+ ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
+ ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),

ASSIGN_FETCH_TYPE_END
};
diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index b303bcdd8ed1..aa333258b1b7 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -176,13 +176,13 @@ Each probe argument follows below syntax.

'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), local array with fixed index (e.g. array[1], var->array[0], var->pointer[2]), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
'$vars' and '$params' special arguments are also available for NAME, '$vars' is expanded to the local variables (including function parameters) which can access at given probe point. '$params' is expanded to only the function parameters.
-'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo. Currently, basic types (u8/u16/u32/u64/s8/s16/s32/s64), signedness casting (u/s), "string" and bitfield are supported. (see TYPES for detail)
+'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo. Currently, basic types (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal integers (x8/x16/x32/x64), signedness casting (u/s), "string" and bitfield are supported. (see TYPES for detail)

On x86 systems %REG is always the short form of the register: for example %AX. %RAX or %EAX is not valid.

TYPES
-----
-Basic types (u8/u16/u32/u64/s8/s16/s32/s64) are integer types. Prefix 's' and 'u' means those types are signed and unsigned respectively. Traced arguments are shown in decimal (signed) or hex (unsigned). You can also use 's' or 'u' to specify only signedness and leave its size auto-detected by perf probe.
+Basic types (u8/u16/u32/u64/s8/s16/s32/s64) and hexadecimal integers (x8/x16/x32/x64) are integer types. Prefix 's' and 'u' means those types are signed and unsigned respectively, and 'x' means that is shown in hexadecimal format. Traced arguments are shown in decimal (signed) or hex (unsigned). You can also use 's' or 'u' to specify only signedness and leave its size auto-detected by perf probe.
String type is a special type, which fetches a "null-terminated" string from kernel space. This means it will fail and store NULL if the string container has been paged out. You can specify 'string' type only for the local variable or structure member which is an array of or a pointer to 'char' or 'unsigned char' type.
Bitfield is another special type, which takes 3 parameters, bit-width, bit-offset, and container-size (usually 32). The syntax is;

--
2.7.4

Next message: Linus Torvalds: "Re: [PATCH v4 54/57] x86/mm: convert arch_within_stack_frames() to use the new unwinder"
Previous message: Arnaldo Carvalho de Melo: "[GIT PULL 00/35] perf/core improvements and fixes"
In reply to: Arnaldo Carvalho de Melo: "[PATCH 28/35] perf probe: Add supported for type casting by the running kernel"
Next in thread: Arnaldo Carvalho de Melo: "[PATCH 11/35] perf bench futex: Use NSEC_PER_USEC"
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