diff options
Diffstat (limited to 'Documentation/trace/kprobetrace.txt')
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index d68ea5fc812b..e4991fb1eedc 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -40,11 +40,12 @@ Synopsis of kprobe_events $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), "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. @@ -53,7 +54,10 @@ 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. Traced arguments are shown in decimal (signed) or hex (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. @@ -62,6 +66,8 @@ 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 ------------------------- |