The synopsys PCI cell used in the later STMicro chips requires code to
be run in order to do IO cycles, rather than just memory mapping the IO
space. Rather than extending the existing SH infrastructure to allow
this, use the GENERIC_IOMAP implmentation to save re-inventing the
wheel.

This set of changes allows the SH to be built with GENERIC_IOMAP
enabled, it just ifdef's out the functions provided by the GENERIC_IOMAP
implementation, and provides a few required missing functions.
Signed-off-by: NDavid McKay <david.mckay@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

GCC does not issue unwind information for function epilogues.
Unfortunately we can catch a signal during an epilogue.  The signal
handler writes the current context and signal return code onto the stack
overwriting previous contents.  During unwinding, libgcc can try to
restore registers from the stack and restores corrupted ones. This can
lead to segmentation, misaligned access and sigbus faults.

For example, consider the following code:

    mov.l   r12,@-r15
    mov.l   r14,@-r15
    sts.l   pr,@-r15
    mov     r15,r14

    <do stuff>

    mov r14, r15
    lds.l @r15+, pr
	<<< SIGNAL HERE
    mov.l @r15+, r14
    mov.l @r15+, r12
    rts

Unwind is aware that pr was pushed to stack in prolog, so tries to
restore it.  Unfortunately it restores the last word of the signal
handler code placed on the stack by the kernel.

This patch tries to avoid the problem by adding a guard region on the
stack between where the function pushes data and where the signal handler
pushes its return code.  We probably don't see this problem often because
exception handling unwinding in an epilogue only occurs due to a pthread
cancel signal.  Also the kernel signal stack handler alignment of 8 bytes
could hide the occurance of this problem sometimes as the stack may not
be trampled at a particular required word.

This is not guaranteed to always work.  It relies on a frame pointer
existing for the function (so it can get the correct sp value) which is
not always the case for the SH4.

Modifications will also be made to libgcc for the case where there is no
fp.
Signed-off-by: NCarl Shaw <carl.shaw@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch fixes a few problems with the existing code in do_address_error().

a) the variable used to printk()d the offending instruction wasn't
   initialized correctly. This is a fix to bug 5727

b) behaviour for CONFIG_CPU_SH2A wasn't correct

c) the 'ignore address error' behaviour didn't update the PC, causing an
   infinite loop.
Signed-off-by: NAndre Draszik <andre.draszik@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch brings the SH4 misaligned trap handler in line with what
happens on ARM:
Add a /proc/cpu/alignment which can be read from to get alignment
trap statistics and written to to influence the behaviour of the
alignment trap handling. The value to write is a bitfield, which
has the following meaning: 1 warn, 2 fixup, 4 signal
In addition, we add a /proc/cpu/kernel_alignment, to enable or
disable warnings in case of kernel code causing alignment errors.

Signed-off by: Andre Draszik <andre.draszik@st.com>
Signed-off-by: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch makes sure we see messages about unaligned access fixups
every now and then. Else especially userspace apps suffering from
bad programming won't ever be noticed...

Signed-off by: Andre Draszik <andre.draszik@st.com>
Signed-off-by: NStuart Menefy <stuart.menefy@st.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The Runtime PM patch for UIO driver implements coarse grained
dynamic power management for UIO devices. With that patch in
place we can get rid of the static clock configuration. Which
in turn makes it possible for cpuidle to enter deeper sleep.
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The runtime PM for SH-Mobile code had platform_bus_notify() as __devinit,
which is rather bogus. Kill off the annotation, which subsequently
silences the section mismatch warnings.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch is V3 of the SuperH Mobile Runtime PM platform bus
implentation matching Rafael's Runtime PM v16.

The code gets invoked from the SuperH specific Runtime PM
platform bus functions that override the weak symbols for:
 - platform_pm_runtime_suspend()
 - platform_pm_runtime_resume()
 - platform_pm_runtime_idle()

This Runtime PM implementation performs two levels of power
management. At the time of platform bus runtime suspend the
clock to the device is stopped instantly. Later on if all
devices within the power domain has their clocks stopped
then the device driver ->runtime_suspend() callbacks are
used to save hardware register state for each device.

Device driver ->runtime_suspend() calls are scheduled from
cpuidle context using platform_pm_runtime_suspend_idle().
When all devices have been fully suspended the processor
is allowed to enter deep sleep from cpuidle.

The runtime resume operation turns on clocks and also
restores registers if needed. It is worth noting that the
devices start in a suspended state and the device driver
is responsible for calling runtime resume before accessing
the actual hardware.

In this particular platform bus implementation runtime
resume is not allowed from interrupt context. Runtime
suspend is however allowed from interrupt context as
long as the synchronous functions are avoided.

[ updated for v17 -- PFM. ]
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The CIE and FDE structs are big enough and accessed regularly enough in
certain configurations to make cacheline alignment useful.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This simplifies the unwinder trap handling, dropping the use of the
special trapa vector and simply piggybacking on top of the BUG support. A
new BUGFLAG_UNWINDER is added for flagging the unwinder fault, before
continuing on with regular BUG dispatch.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

If the oprofile code is built as a module, unwind_stack() as used by the
oprofile backtrace code is not available, causing build breakage.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Allow a DWARF register to have an undefined value. When applied to the
DWARF return address register this lets lets us label a function as
having no direct caller, e.g. kernel_thread_helper().
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

The 'end' member of struct dwarf_fde denotes one byte past the end of
the CFA instruction stream for an FDE. The value of 'end' was being
calcualted incorrectly, it was being set too high. This resulted in
dwarf_cfa_execute_insns() interpreting data past the end of valid
instructions, thus causing all sorts of weird crashes.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

When CONFIG_DWARF_UNWINDER is enabled setup r14 in handle_interrupt, so
that we can figure out what function was running when we were
interrupted.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

We can't assume that if we execute the unwinder code and the unwinder
was already running that it has faulted. Clearly two kernel threads can
invoke the unwinder at the same time and may be running simultaneously.

The previous approach used BUG() and BUG_ON() in the unwinder code to
detect whether the unwinder was incapable of unwinding the stack, and
that the next available unwinder should be used instead. A better
approach is to explicitly invoke a trap handler to switch unwinders when
the current unwinder cannot continue.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

The handling of DW_CFA_val_offset ops was incorrectly using the
DWARF_REG_OFFSET flag but the register's value cannot be calculated
using the DWARF_REG_OFFSET method. Create a new flag to indicate that a
different method must be used to calculate the register's value even
though there is no implementation for DWARF_VAL_OFFSET yet; it's mainly
just a place holder.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

Plug a memory leak in dwarf_unwinder_dump() where we didn't free the
memory that we had previously allocated for the DWARF frames and DWARF
registers.

Now is also a opportune time to implement our own mempool and kmem
cache. It's a good idea to have a certain number of frame and register
objects in reserve at all times, so that we are guaranteed to have our
allocation satisfied even when memory is scarce. Since we have pools to
allocate from we can implement the registers for each frame as a linked
list as opposed to a sparsely populated array. Whilst it's true that the
lookup time for a linked list is larger than for arrays, there's only
usually a maximum of 8 registers per frame. So the overhead isn't that
much of a concern.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

Signed-off-by: NYoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

-tip can't be bothered keeping interfaces stable long enough for anyone
to use them without having their builds broken without notification, so
just ifdef around the problematic symbols until the new interfaces become
available upstream.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch updates the FRQCRA.IFC divisor values for SH7724. Despite
not being initially documented, the / 3 mode is also support for the IFC
division.
Signed-off-by: NKuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

save_regs contains an SR modification without an irqflags annotation,
which resulted in a missing TRACE_IRQS_OFF in the interrupt exception
path on SH-3/SH4.

I've also moved the TRACE_IRQS_OFF/ON annotation when returning from the
interrupt to just before we call __restore_all. This seems like the most
logical place to put this because the annotation is for when we restore
the SR register so we should delay the annotation until as last as
possible.

We were also missing a TRACE_IRQS_OFF in resume_kernel when
CONFIG_PREEMPT is enabled.

The end result is that this fixes up the lockdep engine debugging support
with CONFIG_PREEMPT enabled on all SH-3/4 parts.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch adds "SuperH Mobile Standby Mode [SF]" to the list
of cpuidle sleep modes. If the software latency requirements
from cpuidle are met together with fulfilled hardware
requirements then deep sleep modes can be entered.

Tested on sh7722 and sh7724 with "Sleep Mode", "Sleep Mode + SF"
and "Software Standby Mode + SF" together with a multimedia
work load and flood ping without packet drop.
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch updates the exception handling in the sleep code
for SuperH Mobile. With the patch applied the sleep code
always rewrites the VBR and resumes from the exception vector,
re-initializes hardware and jumps straight to the original
interrupt vector.

Tested on sh7722 and sh7724 with "Sleep Mode", "Sleep Mode + SF"
and "Software Standby Mode + SF" with CONFIG_SUSPEND.
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This moves the initialization over to an early_initcall(). This fixes up
some lockdep interaction issues. At the same time, kill off some
superfluous locking in the init path.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Also, remove the "fix" to DW_CFA_def_cfa_register where we reset the
frame's cfa_offset to 0. This action is incorrect when handling
DW_CFA_def_cfa_register as the DWARF spec specifically states that the
previous contents of cfa_offset should be used with the new
register. The reason that I thought cfa_offset should be reset to 0 was
because it was being assigned a bogus value prior to executing the
DW_CFA_def_cfa_register op. It turns out that the bogus cfa_offset value
came from interpreting .cfi_escape pseudo-ops (those used by the GNU
extensions) as CFA_DW_def_cfa ops.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

The previous hack for calculating the return address for the first frame
we unwind (dwarf_unwinder_dump) didn't always work. The problem was that
it assumed once it read the rule for calculating the return address,
there would be no new rules for calculating it. This isn't true because
the way in which the CFA is calculated can change as you progress
through a function and the return address is figured out using the
CFA. Therefore, the way to calculate the return address can change.

So, instead of using some offset from the beginning of
dwarf_unwind_stack which is just a flakey approach, and instead of
executing instructions from the FDE until the return address is setup,
we now figure out the pc in dwarf_unwind_stack() just before we call
dwarf_cfa_execute_insns().
Signed-off-by: NMatt Fleming <matt@console-pimps.org>

This uses the BITS export as per x86 in order to allow the same Makefile
to be used.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This patch updates the SuperH Mobile sleep assembly code with
support for DBSC memory controller found in the sh7724 processor.

Without this fix the memory hooked up to the sh7724 processor
will never enter self-refresh mode before suspending to ram. The
effect of this is that the memory contents most likeley will be
lost upon resume which may or may not be what you want.
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The way that the CFA is calculated can change as we progress through a
function. If we see a DW_CFA_def_cfa_register op we need to reset the
frame's cfa_offset value which may have been previously setup.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This implements EXPMASK initialization code for SH-4A parts, where it is
possible to disable compat features that will go away in newer cores.
Presently this includes disabling support for non-nop instructions in the
rte delay slot, as well as a sleep instruction being placed in a delay
slot (neither of which the kernel does any longer). As a result of this,
any future offenders will have illegal slot exceptions generated for
them.

Associative writes for the memory-mapped cache array are still left
enabled, until such a point that special cache operations for SH-4A are
provided to move off of the current (and rather dated) SH-4 versions.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Future SH parts do not support any instruction but a nop in the rte delay
slot, so make the change for all offending parts. SH-5 is excluded from
this, and already has its own set of restrictions with regards to rte
delay slot handling.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This inserts a ULONG_MAX entry at the end of the valid entries in the
stack trace buffer so the default code doesn't need to scan to the end of
available slots. This also makes the trace buffer termination behaviour
consistent with the other architectures.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This flags the default unwinder as reliable, as it tends to be reliable
enough for the purposes of the stacktrace buffer. We leave the unreliable
cases for the unwind methods that we know to be completely broken.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This adopts the reliability checks from the x86 stacktrace code so known
bad addresses are not recorded in the stack trace buffer.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

save_stack_trace_tsk() and friends can be called from atomic context (as
triggered by latencytop), and subsequently hit two problematic allocation
points that were using GFP_KERNEL (these were dwarf_unwind_stack() and
dwarf_frame_alloc_regs()). Convert these over to GFP_ATOMIC and get
latencytop working with the DWARF unwinder.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Trying to figure out the best value for DWARF_ARCH_UNWIND_OFFSET is
tricky at best. Various things can change the size (and offset from the
beginning of the function) of the prologue. Notably, turning on ftrace
adds calls to mcount at the beginning of functions, thereby pushing the
prologue further into the function.

So replace DWARF_ARCH_UNWIND_OFFSET with some code that continues to
execute CFA instructions until the value of return address register is
defined. This is safe to do because we know that the return address must
have been pushed onto the frame before our first function call; we just
can't figure out where at compile-time.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The destination address might be unaligned, so set it with
put_unaligned() for safety. This restores the previous behaviour, albeit
through the proper API.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This was using internal symbols for unaligned accesses, bypassing the
exposed interface for variable sized safe accesses. This converts all of
the __get_unaligned_cpuXX() users over to get_unaligned() directly,
relying on the cast to select the proper internal routine.

Additionally, the __put_unaligned_cpuXX() case is superfluous given that
the destination address is aligned in all of the current cases, so just
drop that outright.

Furthermore, this switches to the asm/unaligned.h header instead of the
asm-generic version, which was silently bypassing the SH-4A optimized
unaligned ops.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Annotate various assembly code paths with CFI assembler directives so
that DWARF unwind info is available for the unwinder.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

In order to use DWARF unwinder info the frame register has to contain a
valid value. Whilst GCC takes care of this for C code, we have to do it
ourselves for assembly.
Signed-off-by: NMatt Fleming <matt@console-pimps.org>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>