This cribs the x86 implementation of ftrace_nmi_enter() and friends to
make ftrace_modify_code() NMI safe, particularly on SMP configurations.

For additional notes on the problems involved, see the comment below
ftrace_call_replace().
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Sync up with latest core changes in the syscalls tracing area:

- tracing: Map syscall name to number (syscall_name_to_nr())
- tracing: Call arch_init_ftrace_syscalls at boot
- tracing: add support tracepoint ids (set_syscall_{enter,exit}_id())

Taken from the s390 change.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Needed by ftrace changes in -tip.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Add both dynamic and static function graph tracer support for sh.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Now that I've added TIF_SYSCALL_FTRACE the thread flags do not fit into
a single byte any more. Code testing them now needs to be aware of the
upper and lower bytes.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Ftrace on sh handles nop'ing out trace function calls differently than
other architectures. Instead of inserting NOP instructions in place of
the call to the function tracer we branch over the call instructions
and continue executing the main body of the function.

This patch fixes a bug in the implementation of ftrace_modify_code()
where we check that the old value of the code we're about to replace
is an expected one. In the ftrace_make_call() code path
ftrace_modify_code() was comparing the old instruction value with NOP
instructions. The compare was failing because we never actually insert
NOP instructions. It makes sense to just get rid of the NOP
instructions in ftrace_nop and compare the old code with the address
of the function body if we're expecting ftrace to have nop'd out the
function trace call.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

Use my current email address as my gentoo account will be closed at
some point.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

First cut at dynamic ftrace support.
Signed-off-by: NMatt Fleming <mjf@gentoo.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>