ARM: 7368/1: fault.c: correct how the tsk->[maj|min]_flt gets incremented

commit 8878a539ff19a43cf3729e7562cd528f490246ae was done by me
to make the page fault handler retryable as well as interruptible.

Due to this commit, there is a mistake in the way in which
tsk->[maj|min]_flt counter gets incremented for VM_FAULT_ERROR:
If VM_FAULT_ERROR is returned in the fault flags by handle_mm_fault,
then either maj_flt or min_flt will get incremented. This is wrong
as in the case of a VM_FAULT_ERROR we need to be skip ahead to the
error handling code in do_page_fault.

Added a check after the call to __do_page_fault() to check for
(fault & VM_FAULT_ERROR).

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7377/1: vic: re-read status register before dispatching each IRQ handler

handle_IRQ may briefly cause interrupts to be re-enabled during soft IRQ
processing on the exit path, leading to nested handling of VIC interrupts.

Since the current code does not re-read the VIC_IRQ_STATUS register, this
can lead to multiple invocations of the same interrupt handler and
spurious interrupts to be reported.

This patch changes the VIC interrupt dispatching code to re-read the
status register each time, avoiding duplicate invocations of the same
handler.

Acked-and-Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>

Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7366/3: amba: Remove AMBA level regulator support

The AMBA bus regulator support is being used to model on/off switches
for power domains which isn't terribly idiomatic for modern kernels with
the generic power domain code and creates integration problems on platforms
which don't use regulators for their power domains as it's hard to tell
the difference between a regulator that is needed but failed to be provided
and one that isn't supposed to be there (though DT does make that easier).

Platforms that wish to use the regulator API to manage their power domains
can indirect via the power domain interface.

This feature is only used with the vape supply of the db8500 PRCMU
driver which supplies the UARTs and MMC controllers, none of which have
support for managing vcore at runtime in mainline (only pl022 SPI
controller does).  Update that supply to have an always_on constraint
until the power domain support for the system is updated so that it is
enabled for these users, this is likely to have no impact on practical
systems as probably at least one of these devices will be active and
cause AMBA to hold the supply on anyway.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7379/1: DT: fix atags_to_fdt() second call site

atags_to_fdt() returns 1 when it fails to find a valid FDT signature.
The CONFIG_ARM_ATAG_DTB_COMPAT code is supposed to retry with another
location, but only does so when the initial call doesn't fail.

Fix this by using the correct condition in the assembly code.

Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7380/1: DT: do not add a zero-sized memory property

Some bootloaders are broken enough to expose an ATAG_MEM with
a null size. Converting such tag to a memory node leads to
an unbootable system.

Skip over zero sized ATAG_MEM to avoid this situation.

Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7381/1: nommu: fix typo in mm/Kconfig

The description for the CPU_HIGH_VECTOR Kconfig option for nommu builds
doesn't make any sense.

This patch fixes up the trivial grammatical error.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7383/1: nommu: populate vectors page from paging_init

Commit 94e5a85b ("ARM: earlier initialization of vectors page") made it
the responsibility of paging_init to initialise the vectors page.

This patch adds a call to early_trap_init for the !CONFIG_MMU case,
placing the vectors at CONFIG_VECTORS_BASE.

Cc: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
PCI: Fix regression in pci_restore_state(), v3

Commit 26f41062f28d ("PCI: check for pci bar restore completion and
retry") attempted to address problems with PCI BAR restoration on
systems where FLR had not been completed before pci_restore_state() was
called, but it did that in an utterly wrong way.

First off, instead of retrying the writes for the BAR registers only, it
did that for all of the PCI config space of the device, including the
status register (whose value after the write quite obviously need not be
the same as the written one).  Second, it added arbitrary delay to
pci_restore_state() even for systems where the PCI config space
restoration was successful at first attempt.  Finally, the mdelay(10) it
added to every iteration of the writing loop was way too much of a delay
for any reasonable device.

All of this actually caused resume failures for some devices on Mikko's
system.

To fix the regression, make pci_restore_state() only retry the writes
for BAR registers and only wait if the first read from the register
doesn't return the written value.  Additionaly, make it wait for 1 ms,
instead of 10 ms, after every failing attempt to write into config
space.

Reported-by: Mikko Vinni <mmvinni@yahoo.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ARM: 7359/2: smp_twd: Only wait for reprogramming on active cpus

During booting of cpu1, there is a short window where cpu1
is online, but not active where cpu1 is occupied by waiting
to become active. If cpu0 then decides to schedule something
on cpu1 and wait for it to complete, before cpu0 has set
cpu1 active, we have a deadlock.

Typically it's this CPU frequency transition that happens at
this time, so let's just not wait for it to happen, it will
happen whenever the CPU eventually comes online instead.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Reviewed-by: Rickard Andersson <rickard.andersson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7382/1: mm: truncate memory banks to fit in 4GB space for classic MMU

If a bank of memory spanning the 4GB boundary is added on a !CONFIG_LPAE
kernel then we will hang early during boot since the memory bank will
have wrapped around to zero.

This patch truncates memory banks for !LPAE configurations when the end
address is not representable in 32 bits.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7384/1: ThumbEE: Disable userspace TEEHBR access for !CONFIG_ARM_THUMBEE

Currently when ThumbEE is not enabled (!CONFIG_ARM_THUMBEE) the ThumbEE
register states are not saved/restored at context switch. The default state
of the ThumbEE Ctrl register (TEECR) allows userspace accesses to the
ThumbEE Base Handler register (TEEHBR). This can cause unexpected behaviour
when people use ThumbEE on !CONFIG_ARM_THUMBEE kernels, as well as allowing
covert communication - eg between userspace tasks running inside chroot
jails.

This patch sets up TEECR in order to prevent user-space access to TEEHBR
when !CONFIG_ARM_THUMBEE. In this case, tasks are sent SIGILL if they try to
access TEEHBR.

Cc: stable@vger.kernel.org
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7386/1: jump_label: fixup for rename to static_key

c5905afb0 ("static keys: Introduce 'struct static_key'...") renamed
struct jump_label_key to struct static_key.  Fixup ARM for this to
eliminate these build warnings:

  include/linux/jump_label.h:113:2:
  warning: passing argument 1 of 'arch_static_branch' from incompatible pointer type
  include/asm/jump_label.h:17:82:
  note: expected 'struct jump_label_key *' but argument is of type 'struct static_key *'

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
x86-32: fix up strncpy_from_user() sign error

The 'max' range needs to be unsigned, since the size of the user address
space is bigger than 2GB.

We know that 'count' is positive in 'long' (that is checked in the
caller), so we will truncate 'max' down to something that fits in a
signed long, but before we actually do that, that comparison needs to be
done in unsigned.

Bug introduced in commit 92ae03f2ef99 ("x86: merge 32/64-bit versions of
'strncpy_from_user()' and speed it up").  On x86-64 you can't trigger
this, since the user address space is much smaller than 63 bits, and on
x86-32 it works in practice, since you would seldom hit the strncpy
limits anyway.

I had actually tested the corner-cases, I had only tested them on
x86-64.  Besides, I had only worried about the case of a pointer *close*
to the end of the address space, rather than really far away from it ;)

This also changes the "we hit the user-specified maximum" to return
'res', for the trivial reason that gcc seems to generate better code
that way.  'res' and 'count' are the same in that case, so it really
doesn't matter which one we return.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm

Pull ARM fixes from Russell King:
 "Nothing too disasterous, the biggest thing being the removal of the
  regulator support for vcore in the AMBA driver; only one SoC was using
  this and it got broken during the last merge window, which then
  started causing problems for other people.  Mutual agreement was
  reached for it to be removed."

* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7386/1: jump_label: fixup for rename to static_key
  ARM: 7384/1: ThumbEE: Disable userspace TEEHBR access for !CONFIG_ARM_THUMBEE
  ARM: 7382/1: mm: truncate memory banks to fit in 4GB space for classic MMU
  ARM: 7359/2: smp_twd: Only wait for reprogramming on active cpus
  ARM: 7383/1: nommu: populate vectors page from paging_init
  ARM: 7381/1: nommu: fix typo in mm/Kconfig
  ARM: 7380/1: DT: do not add a zero-sized memory property
  ARM: 7379/1: DT: fix atags_to_fdt() second call site
  ARM: 7366/3: amba: Remove AMBA level regulator support
  ARM: 7377/1: vic: re-read status register before dispatching each IRQ handler
  ARM: 7368/1: fault.c: correct how the tsk->[maj|min]_flt gets incremented
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