trace doc: convert trace/kprobetrace.txt to rst format

This converts the plain text documentation to reStructuredText format and
add it into Sphinx TOC tree. No essential content change.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 182 deletions

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
deleted file mode 100644
index 1a3a3d6bc2a8..000000000000
--- a/Documentation/trace/kprobetrace.txt
+++ /dev/null
@@ -1,182 +0,0 @@
-                        Kprobe-based Event Tracing
-                        ==========================
-
-                 Documentation is written by Masami Hiramatsu
-
-
-Overview
---------
-These events are similar to tracepoint based events. Instead of Tracepoint,
-this is based on kprobes (kprobe and kretprobe). So it can probe wherever
-kprobes can probe (this means, all functions except those with
-__kprobes/nokprobe_inline annotation and those marked NOKPROBE_SYMBOL).
-Unlike the Tracepoint based event, this can be added and removed
-dynamically, on the fly.
-
-To enable this feature, build your kernel with CONFIG_KPROBE_EVENTS=y.
-
-Similar to the events tracer, this doesn't need to be activated via
-current_tracer. Instead of that, add probe points via
-/sys/kernel/debug/tracing/kprobe_events, and enable it via
-/sys/kernel/debug/tracing/events/kprobes/<EVENT>/enabled.
-
-
-Synopsis of kprobe_events
--------------------------
-  p[:[GRP/]EVENT] [MOD:]SYM[+offs]|MEMADDR [FETCHARGS]	: Set a probe
-  r[MAXACTIVE][:[GRP/]EVENT] [MOD:]SYM[+0] [FETCHARGS]	: Set a return probe
-  -:[GRP/]EVENT						: Clear a probe
-
- GRP		: Group name. If omitted, use "kprobes" for it.
- EVENT		: Event name. If omitted, the event name is generated
-		  based on SYM+offs or MEMADDR.
- MOD		: Module name which has given SYM.
- SYM[+offs]	: Symbol+offset where the probe is inserted.
- MEMADDR	: Address where the probe is inserted.
- MAXACTIVE	: Maximum number of instances of the specified function that
-		  can be probed simultaneously, or 0 for the default value
-		  as defined in Documentation/kprobes.txt section 1.3.1.
-
- FETCHARGS	: Arguments. Each probe can have up to 128 args.
-  %REG		: Fetch register REG
-  @ADDR		: Fetch memory at ADDR (ADDR should be in kernel)
-  @SYM[+|-offs]	: Fetch memory at SYM +|- offs (SYM should be a data symbol)
-  $stackN	: Fetch Nth entry of stack (N >= 0)
-  $stack	: Fetch stack address.
-  $retval	: Fetch return value.(*)
-  $comm		: Fetch current task comm.
-  +|-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), 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.
-
-Types
------
-Several types are supported for fetch-args. Kprobe tracer will access memory
-by given type. Prefix 's' and 'u' means those types are signed and unsigned
-respectively. 'x' prefix implies it is unsigned. Traced arguments are shown
-in decimal ('s' and 'u') or hexadecimal ('x'). Without type casting, 'x32'
-or 'x64' is used depends on the architecture (e.g. x86-32 uses x32, and
-x86-64 uses x64).
-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.
-Bitfield is another special type, which takes 3 parameters, bit-width, bit-
-offset, and container-size (usually 32). The syntax is;
-
- b<bit-width>@<bit-offset>/<container-size>
-
-For $comm, the default type is "string"; any other type is invalid.
-
-
-Per-Probe Event Filtering
--------------------------
- Per-probe event filtering feature allows you to set different filter on each
-probe and gives you what arguments will be shown in trace buffer. If an event
-name is specified right after 'p:' or 'r:' in kprobe_events, it adds an event
-under tracing/events/kprobes/<EVENT>, at the directory you can see 'id',
-'enabled', 'format' and 'filter'.
-
-enabled:
-  You can enable/disable the probe by writing 1 or 0 on it.
-
-format:
-  This shows the format of this probe event.
-
-filter:
-  You can write filtering rules of this event.
-
-id:
-  This shows the id of this probe event.
-
-
-Event Profiling
----------------
- You can check the total number of probe hits and probe miss-hits via
-/sys/kernel/debug/tracing/kprobe_profile.
- The first column is event name, the second is the number of probe hits,
-the third is the number of probe miss-hits.
-
-
-Usage examples
---------------
-To add a probe as a new event, write a new definition to kprobe_events
-as below.
-
-  echo 'p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack)' > /sys/kernel/debug/tracing/kprobe_events
-
- This sets a kprobe on the top of do_sys_open() function with recording
-1st to 4th arguments as "myprobe" event. Note, which register/stack entry is
-assigned to each function argument depends on arch-specific ABI. If you unsure
-the ABI, please try to use probe subcommand of perf-tools (you can find it
-under tools/perf/).
-As this example shows, users can choose more familiar names for each arguments.
-
-  echo 'r:myretprobe do_sys_open $retval' >> /sys/kernel/debug/tracing/kprobe_events
-
- This sets a kretprobe on the return point of do_sys_open() function with
-recording return value as "myretprobe" event.
- You can see the format of these events via
-/sys/kernel/debug/tracing/events/kprobes/<EVENT>/format.
-
-  cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format
-name: myprobe
-ID: 780
-format:
-        field:unsigned short common_type;       offset:0;       size:2; signed:0;
-        field:unsigned char common_flags;       offset:2;       size:1; signed:0;
-        field:unsigned char common_preempt_count;       offset:3; size:1;signed:0;
-        field:int common_pid;   offset:4;       size:4; signed:1;
-
-        field:unsigned long __probe_ip; offset:12;      size:4; signed:0;
-        field:int __probe_nargs;        offset:16;      size:4; signed:1;
-        field:unsigned long dfd;        offset:20;      size:4; signed:0;
-        field:unsigned long filename;   offset:24;      size:4; signed:0;
-        field:unsigned long flags;      offset:28;      size:4; signed:0;
-        field:unsigned long mode;       offset:32;      size:4; signed:0;
-
-
-print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->__probe_ip,
-REC->dfd, REC->filename, REC->flags, REC->mode
-
- You can see that the event has 4 arguments as in the expressions you specified.
-
-  echo > /sys/kernel/debug/tracing/kprobe_events
-
- This clears all probe points.
-
- Or,
-
-  echo -:myprobe >> kprobe_events
-
- This clears probe points selectively.
-
- Right after definition, each event is disabled by default. For tracing these
-events, you need to enable it.
-
-  echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable
-  echo 1 > /sys/kernel/debug/tracing/events/kprobes/myretprobe/enable
-
- And you can see the traced information via /sys/kernel/debug/tracing/trace.
-
-  cat /sys/kernel/debug/tracing/trace
-# tracer: nop
-#
-#           TASK-PID    CPU#    TIMESTAMP  FUNCTION
-#              | |       |          |         |
-           <...>-1447  [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0
-           <...>-1447  [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $retval=fffffffffffffffe
-           <...>-1447  [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6
-           <...>-1447  [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $retval=3
-           <...>-1447  [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10
-           <...>-1447  [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $retval=3
-
-
- Each line shows when the kernel hits an event, and <- SYMBOL means kernel
-returns from SYMBOL(e.g. "sys_open+0x1b/0x1d <- do_sys_open" means kernel
-returns from do_sys_open to sys_open+0x1b).
-