linux-toradex.git/drivers/staging, branch v3.14.41

vm: add VM_FAULT_SIGSEGV handling support

2015-04-29T08:31:55+00:00

commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream.

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai 
Tested-by: Jan Engelhardt 
Acked-by: Heiko Carstens  # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds 
[shengyong: Backport to 3.14
 - adjust context
 - ignore modification for arch nios2, because 3.14 does not support it
 - add SIGSEGV handling to powerpc/cell spu_fault.c, because 3.14 does not
   separate it to copro_fault.c
 - add SIGSEGV handling to mm/memory.c, because 3.14 does not separate it
   to gup.c
]
Signed-off-by: Sheng Yong 
Signed-off-by: Greg Kroah-Hartman

move d_rcu from overlapping d_child to overlapping d_alias

2015-04-29T08:31:54+00:00

commit 946e51f2bf37f1656916eb75bd0742ba33983c28 upstream.

move d_rcu from overlapping d_child to overlapping d_alias

Signed-off-by: Al Viro 
Cc: Ben Hutchings 
[hujianyang: Backported to 3.14 refer to the work of Ben Hutchings in 3.2:
 - Apply name changes in all the different places we use d_alias and d_child
 - Move the WARN_ON() in __d_free() to d_free() as we don't have dentry_free()]
Signed-off-by: hujianyang 
Signed-off-by: Greg Kroah-Hartman

vt6655: RFbSetPower fix missing rate RATE_12M

2015-04-13T12:03:02+00:00

commit 40c8790bcb7ac74f3038153cd09310e220c6a1df upstream.

When the driver sets this rate a power of zero value is set causing
data flow stoppage until another rate is tried.

Signed-off-by: Malcolm Priestley 
Signed-off-by: Greg Kroah-Hartman

staging: vt6656: vnt_rf_setpower: fix missing rate RATE_12M

2015-04-13T12:03:01+00:00

commit 163fe301b9f78b6de57d0014eafe504fd20c0cd4 upstream.

When the driver sets this rate a power of zero value is set causing
data flow stoppage until another rate is tried.

Signed-off-by: Malcolm Priestley 
Signed-off-by: Greg Kroah-Hartman

iio: mxs-lradc: fix merge error

2015-03-26T14:06:49+00:00

Commit e7f3db14eacaf1993a70b1517582603dfdf34988 (89bb35e200bee745c539a96666e0792301ca40f1 upstream) was backported incorrectly by me, so fix it up, as the driver is now broken.

Sorry about that.

Reported-by: Kristina Martšenko 
Cc: Marek Vasut 
Cc: Jonathan Cameron 
Signed-off-by: Greg Kroah-Hartman

staging: comedi: cb_pcidas64: fix incorrect AI range code handling

2015-03-18T12:31:33+00:00

commit be8e89087ec2d2c8a1ad1e3db64bf4efdfc3c298 upstream.

The hardware range code values and list of valid ranges for the AI
subdevice is incorrect for several supported boards.  The hardware range
code values for all boards except PCI-DAS4020/12 is determined by
calling `ai_range_bits_6xxx()` based on the maximum voltage of the range
and whether it is bipolar or unipolar, however it only returns the
correct hardware range code for the PCI-DAS60xx boards.  For
PCI-DAS6402/16 (and /12) it returns the wrong code for the unipolar
ranges.  For PCI-DAS64/Mx/16 it returns the wrong code for all the
ranges and the comedi range table is incorrect.

Change `ai_range_bits_6xxx()` to use a look-up table pointed to by new
member `ai_range_codes` of `struct pcidas64_board` to map the comedi
range table indices to the hardware range codes.  Use a new comedi range
table for the PCI-DAS64/Mx/16 boards (and the commented out variants).

Signed-off-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

staging: comedi: comedi_compat32.c: fix COMEDI_CMD copy back

2015-03-18T12:31:32+00:00

commit 42b8ce6f55facfa101462e694d33fc6bca471138 upstream.

`do_cmd_ioctl()` in "comedi_fops.c" handles the `COMEDI_CMD` ioctl.
This returns `-EAGAIN` if it has copied a modified `struct comedi_cmd`
back to user-space.  (This occurs when the low-level Comedi driver's
`do_cmdtest()` handler returns non-zero to indicate a problem with the
contents of the `struct comedi_cmd`, or when the `struct comedi_cmd` has
the `CMDF_BOGUS` flag set.)

`compat_cmd()` in "comedi_compat32.c" handles the 32-bit compatible
version of the `COMEDI_CMD` ioctl.  Currently, it never copies a 32-bit
compatible version of `struct comedi_cmd` back to user-space, which is
at odds with the way the regular `COMEDI_CMD` ioctl is handled.  To fix
it, change `compat_cmd()` to copy a 32-bit compatible version of the
`struct comedi_cmd` back to user-space when the main ioctl handler
returns `-EAGAIN`.

Signed-off-by: Ian Abbott 
Reviewed-by: H Hartley Sweeten 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

iio: mxs-lradc: only update the buffer when its conversions have finished

2015-03-18T12:31:26+00:00

commit 89bb35e200bee745c539a96666e0792301ca40f1 upstream.

Using the touchscreen while running buffered capture results in the
buffer reporting lots of wrong values, often just zeros. This is because
we push readings to the buffer every time a touchscreen interrupt
arrives, including when the buffer's own conversions have not yet
finished. So let's only push to the buffer when its conversions are
ready.

Signed-off-by: Kristina Martšenko 
Reviewed-by: Marek Vasut 
Signed-off-by: Jonathan Cameron 
Signed-off-by: Greg Kroah-Hartman

iio: mxs-lradc: make ADC reads not unschedule touchscreen conversions

2015-03-18T12:31:26+00:00

commit 6abe0300a1d5242f4ff89257197f284679af1a06 upstream.

Reading a channel through sysfs, or starting a buffered capture, can
occasionally turn off the touchscreen.

This is because the read_raw() and buffer preenable()/postdisable()
callbacks unschedule current conversions on all channels. If a delay
channel happens to schedule a touchscreen conversion at the same time,
the conversion gets cancelled and the touchscreen sequence stops.

This is probably related to this note from the reference manual:

	"If a delay group schedules channels to be sampled and a manual
	write to the schedule field in CTRL0 occurs while the block is
	discarding samples, the LRADC will switch to the new schedule
	and will not sample the channels that were previously scheduled.
	The time window for this to happen is very small and lasts only
	while the LRADC is discarding samples."

So make the callbacks only unschedule conversions for the channels they
use. This means channel 0 for read_raw() and channels 0-5 for the buffer
(if the touchscreen is enabled). Since the touchscreen uses different
channels (6 and 7), it no longer gets turned off.

This is tested and fixes the issue on i.MX28, but hasn't been tested on
i.MX23.

Signed-off-by: Kristina Martšenko 
Reviewed-by: Marek Vasut 
Signed-off-by: Jonathan Cameron 
Signed-off-by: Greg Kroah-Hartman

iio: mxs-lradc: make ADC reads not disable touchscreen interrupts

2015-03-18T12:31:26+00:00

commit 86bf7f3ef7e961e91e16dceb31ae0f583483b204 upstream.

Reading a channel through sysfs, or starting a buffered capture, will
currently turn off the touchscreen. This is because the read_raw() and
buffer preenable()/postdisable() callbacks disable interrupts for all
LRADC channels, including those the touchscreen uses.

So make the callbacks only disable interrupts for the channels they use.
This means channel 0 for read_raw() and channels 0-5 for the buffer (if
the touchscreen is enabled). Since the touchscreen uses different
channels (6 and 7), it no longer gets turned off.

Note that only i.MX28 is affected by this issue, i.MX23 should be fine.

Signed-off-by: Kristina Martšenko 
Reviewed-by: Marek Vasut 
Signed-off-by: Jonathan Cameron 
Signed-off-by: Greg Kroah-Hartman