ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict

Introduce FTRACE_OPS_FL_IPMODIFY to avoid conflict among
ftrace users who may modify regs->ip to change the execution
path. If two or more users modify the regs->ip on the same
function entry, one of them will be broken. So they must add
IPMODIFY flag and make sure that ftrace_set_filter_ip() succeeds.

Note that ftrace doesn't allow ftrace_ops which has IPMODIFY
flag to have notrace hash, and the ftrace_ops must have a
filter hash (so that the ftrace_ops can hook only specific
entries), because it strongly depends on the address and
must be allowed for only few selected functions.

Link: http://lkml.kernel.org/r/[email protected]

Cc: Jiri Kosina <[email protected]>
Cc: Seth Jennings <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Vojtech Pavlik <[email protected]>
Cc: Miroslav Benes <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Namhyung Kim <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
[ fixed up some of the comments ]
Signed-off-by: Steven Rostedt <[email protected]>

0 files changed, 0 insertions, 0 deletions