On no-MMU systems the application a5 register can be overwitten with the
address of the process data segment when processing application signals.
For flat format applications compiled with full absolute relocation this
effectively corrupts the a5 register on signal processing - and this very
quickly leads to process crash and often takes out the whole system with
a panic as well.

This has no effect on flat format applications compiled with the more
common PIC methods (such as -msep-data). These format applications reserve
a5 for the pointer to the data segment anyway - so it doesn't change it.

A long time ago the a5 register was used in the code packed into the user
stack to enable signal return processing. And so it had to be restored on
end of signal cleanup processing back to the original a5 user value. This
was historically done by saving away a5 in the sigcontext structure. At
some point (a long time back it seems) the a5 restore process was changed
and it was hard coded to put the user data segment address directly into a5.
Which is ok for the common PIC compiled application case, but breaks the
full relocation application code.

We no longer use this type of signal handling mechanism and so we don't
need to do anything special to save and restore a5 at all now. So remove the
code that hard codes a5 to the address of the user data segment.

Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>

Pull RTC updates from Alexandre Belloni:
 "RTC for 4.8

  Cleanups:
   - huge cleanup of rtc-generic and char/genrtc this allowed to cleanup
     rtc-cmos, rtc-sh, rtc-m68k, rtc-powerpc and rtc-parisc
   - move mn10300 to rtc-cmos

  Subsystem:
   - fix wakealarms after hibernate
   - multiples fixes for rctest
   - simplify implementations of .read_alarm

  New drivers:
   - Maxim MAX6916

  Drivers:
   - ds1307: fix weekday
   - m41t80: add wakeup support
   - pcf85063: add support for PCF85063A variant
   - rv8803: extend i2c fix and other fixes
   - s35390a: fix alarm reading, this fixes instant reboot after
     shutdown for QNAP TS-41x
   - s3c: clock fixes"

* tag 'rtc-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (65 commits)
  rtc: rv8803: Clear V1F when setting the time
  rtc: rv8803: Stop the clock while setting the time
  rtc: rv8803: Always apply the I²C workaround
  rtc: rv8803: Fix read day of week
  rtc: rv8803: Remove the check for valid time
  rtc: rv8803: Kconfig: Indicate rx8900 support
  rtc: asm9260: remove .owner field for driver
  rtc: at91sam9: Fix missing spin_lock_init()
  rtc: m41t80: add suspend handlers for alarm IRQ
  rtc: m41t80: make it a real error message
  rtc: pcf85063: Add support for the PCF85063A device
  rtc: pcf85063: fix year range
  rtc: hym8563: in .read_alarm set .tm_sec to 0 to signal minute accuracy
  rtc: explicitly set tm_sec = 0 for drivers with minute accurancy
  rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq()
  rtc: s3c: Remove unnecessary call to disable already disabled clock
  rtc: abx80x: use devm_add_action_or_reset()
  rtc: m41t80: use devm_add_action_or_reset()
  rtc: fix a typo and reduce three empty lines to one
  rtc: s35390a: improve two comments in .set_alarm
  ...

The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer.  Thus the pointer can point to const data.
However the attributes do not have to be a bitfield.  Instead unsigned
long will do fine:

1. This is just simpler.  Both in terms of reading the code and setting
   attributes.  Instead of initializing local attributes on the stack
   and passing pointer to it to dma_set_attr(), just set the bits.

2. It brings safeness and checking for const correctness because the
   attributes are passed by value.

Semantic patches for this change (at least most of them):

    virtual patch
    virtual context

    @r@
    identifier f, attrs;

    @@
    f(...,
    - struct dma_attrs *attrs
    + unsigned long attrs
    , ...)
    {
    ...
    }

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

and

    // Options: --all-includes
    virtual patch
    virtual context

    @r@
    identifier f, attrs;
    type t;

    @@
    t f(..., struct dma_attrs *attrs);

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The q40 platform is the only machine in the kernel that provides
RTC_PLL_GET/RTC_PLL_SET ioctl commands in its rtc through the
mach_get_rtc_pll/mach_set_rtc_pll callbacks.

However, this currenctly works only in the old-style genrtc
driver, not the (somewhat) modern rtc-generic driver replacing
it. This adds an ioctl implementation to the m68k generic_rtc_ops
in order to let both drivers provide the same API.

After this, we should be able to remove support for genrtc
from the m68k architecture.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and m68k has another abstraction on top, which is a bit
silly.

This changes the m68k rtc-generic device to provide its
rtc_class_ops directly, to reduce the number of layers
by one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

Pull m68knommu updates from Greg Ungerer:
 "The main change is the removal of the bit-rotten 68360 support.  Also
  a fix to always make the ethernet FEC platform info available"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68knommu: remove obsolete 68360 support
  m68knommu: fix FEC platform device registration when driver is modular

Pull m68k updates from Geert Uytterhoeven.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: Fix misspellings in comments.
  m68k: Use conventional function parameters for do_sigreturn
  zorro: Use kobj_to_dev()

Remove the obsolete Motorola/Freescale 68360 SoC support. It has been
bit rotting for many years with little active use in mainlne. There has
been no serial driver support for many years, so it is largely not
useful in its current state.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>

Create conventional stack parameters for the calls to do_sigreturn and
do_rt_sigreturn. The current C code for do_sigreturn and do_rt_sigreturn
dig into the stack to create local pointers to the saved switch stack
and the pt_regs structs.

The motivation for this change is a problem with non-MMU targets that
have broken signal return paths on newer versions of gcc. It appears as
though gcc has determined that the pointers into the saved stack structs,
and the saved structs themselves, are function parameters and updates to
them will be lost on function return, so they are optimized away. This
results in large parts of restore_sigcontext() and mangle_kernel_stack()
functions being removed. Of course this results in non-functional code
causing kernel oops. This problem has been observed with gcc version
5.2 and 5.3, and probably exists in earlier versions as well.

Using conventional stack parameter pointers passed to these functions has
the advantage of the code here not needing to know the exact details of
how the underlying entry handler layed these structs out on the stack.
So the rather ugly pointer setup casting and arg referencing can be
removed.

The resulting code after this change is a few bytes larger (due to the
overhead of creating the stack args and their tear down). Not being hot
paths I don't think this is too much of a problem here.

An alternative solution is to put a barrier() in the do_sigreturn() code,
but this doesn't feel quite as clean as this solution.

This change has been compile tested on all defconfigs, and run tested on
Atari (through aranym), ColdFire with MMU (M5407EVB) and ColdFire with
no-MMU (QEMU and M5208EVB).

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>