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Diffstat (limited to 'Documentation/trace/uprobetracer.txt')
| -rw-r--r-- | Documentation/trace/uprobetracer.txt | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt index d9c3e682312..f1cf9a34ad9 100644 --- a/Documentation/trace/uprobetracer.txt +++ b/Documentation/trace/uprobetracer.txt @@ -19,18 +19,44 @@ user to calculate the offset of the probepoint in the object. Synopsis of uprobe_tracer ------------------------- - p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] : Set a uprobe - r[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS] : Set a return uprobe (uretprobe) - -:[GRP/]EVENT : Clear uprobe or uretprobe event + p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe + r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe) + -:[GRP/]EVENT : Clear uprobe or uretprobe event GRP : Group name. If omitted, "uprobes" is the default value. EVENT : Event name. If omitted, the event name is generated based - on SYMBOL+offs. + on PATH+OFFSET. PATH : Path to an executable or a library. - SYMBOL[+offs] : Symbol+offset where the probe is inserted. + OFFSET : Offset where the probe is inserted. 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.(*) + +|-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. + + (*) only for return probe. + (**) this is useful for fetching a field of data structures. + +Types +----- +Several types are supported for fetch-args. Uprobe tracer will access memory +by given type. Prefix 's' and 'u' means those types are signed and unsigned +respectively. Traced arguments are shown in decimal (signed) or hex (unsigned). +String type is a special type, which fetches a "null-terminated" string from +user space. +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> + Event Profiling --------------- |