128 bytes is sufficient for the register window save area, but the
calling conventions allow the callee to save up to 6 incoming argument
registers into the stack frame after the register window save area.

This means a minimal stack frame is 176 bytes (128 + (6 * 8)).

This fixes random crashes when using the function tracer.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: David S. Miller <davem@davemloft.net>

It's the only way we'll be able to implement the function
graph tracer properly.

A positive is that we no longer have to worry about the
linker over-optimizing the tail call, since we don't
use a tail call any more.

Signed-off-by: David S. Miller <davem@davemloft.net>

The generic stack tracer does this job just as well.

Signed-off-by: David S. Miller <davem@davemloft.net>

Check function_trace_stop at ftrace_caller

Toss mcount_call and dummy call of ftrace_stub, unnecessary.

Document problems we'll have if the final kernel image link
ever turns on relaxation.

Properly size 'ftrace_call' so it looks right when inspecting
instructions under gdb et al.

Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 4f70f7a91bffdcc39f088748dc678953eb9a3fbd
(sparc64: Implement IRQ stacks.) has two bugs.

First, the softirq range check forgets to subtract STACK_BIAS
before comparing with %sp.  Next, on failure the wrong label
is jumped to, resulting in a bogus stack being loaded.

Reported-by: Igor Kovalenko <igor.v.kovalenko@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

o Renamed files in sparc64 to <name>_64.S when identical
  to sparc32 files.
o iomap.c were equal for sparc32 and sparc64
o adjusted sparc/Makefile now we have only one lib/

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>