ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork

Since commit 6a1c53124aa1 the user writeable TLS register was zeroed to
prevent it from being used as a covert channel between two tasks.

There are more and more applications coming to Windows RT,
Wine could support them, but mostly they expect to have
the thread environment block (TEB) in TPIDRURW.

This patch preserves that register per thread instead of clearing it.
Unlike the TPIDRURO, which is already switched, the TPIDRURW
can be updated from userspace so needs careful treatment in the case that we
modify TPIDRURW and call fork(). To avoid this we must always read
TPIDRURW in copy_thread.

Change-Id: Ib1e25be7b9faa846ba5335aad2574e21a1246066
Signed-off-by: André Hentschel <nerv@dawncrow.de>
Signed-off-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>
Git-commit: a4780adeefd042482f624f5e0d577bf9cdcbb760
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: poison the vectors page

Fill the empty regions of the vectors page with an exception generating
instruction.  This ensures that any inappropriate branch to the vector
page is appropriately trapped, rather than just encountering some code
to execute.  (The vectors page was filled with zero before, which
corresponds with the "andeq r0, r0, r0" instruction - a no-op.)

Change-Id: I74c0105a2bcb3b78d9fc8b105a05c0fc269ba400
Cc: <stable@vger.kernel.org>
Acked-by Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: f928d4f2a86f46b030fa0850385b4391fc2b5918
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: poison memory between kuser helpers

Poison the memory between each kuser helper.  This ensures that any
branch between the kuser helpers will be appropriately trapped.

Change-Id: Ifa4abe51d3dd89a96670a8609cd472fa03988e7e
Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 5b43e7a383d69381ffe53423e46dd0fafae07da3
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: move vector stubs

Move the machine vector stubs into the page above the vector page,
which we can prevent from being visible to userspace.  Also move
the reset stub, and place the swi vector at a location that the
'ldr' can get to it.

This hides pointers into the kernel which could give valuable
information to attackers, and reduces the number of exploitable
instructions at a fixed address.

Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 19accfd373847ac3d10623c5d20f948846299741
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

ARM: use linker magic for vectors and vector stubs

Use linker magic to create the vectors and vector stubs: we can tell the
linker to place them at an appropriate VMA, but keep the LMA within the
kernel.  This gets rid of some unnecessary symbol manipulation, and
have the linker calculate the relocations appropriately.

Change-Id: I694f6b651e60fccd7e3c818f981a3883f9c212de
Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: b9b32bf70f2fb710b07c94e13afbc729afe221da
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: squashed 19accfd and b9b32bf because 19accfd
			broke build]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: fiq: change FIQ_START to a variable

The commit a2be01b (ARM: only include mach/irqs.h for !SPARSE_IRQ)
makes mach/irqs.h only be included for !SPARSE_IRQ build.  There are
a nubmer of platforms have FIQ_START defined in mach/irqs.h for FIQ
support.

  arch/arm/mach-rpc/include/mach/irqs.h:#define FIQ_START         64
  arch/arm/mach-s3c24xx/include/mach/irqs.h:#define FIQ_START             IRQ_EINT0
  arch/arm/plat-mxc/include/mach/irqs.h:#define FIQ_START 0

If SPARSE_IRQ is enabled for any of these platforms, the following
compile error will be seen.

  arch/arm/kernel/fiq.c: In function ‘enable_fiq’:
  arch/arm/kernel/fiq.c:127:19: error: ‘FIQ_START’ undeclared (first use in this function)
  arch/arm/kernel/fiq.c:127:19: note: each undeclared identifier is reported only once for each function it appears in
  arch/arm/kernel/fiq.c: In function ‘disable_fiq’:
  arch/arm/kernel/fiq.c:132:20: error: ‘FIQ_START’ undeclared (first use in this function)

The patch changes fiq code to have init_FIQ take FIQ_START from
platforms as a parameter and assign it to variable fiq_start which
is to replace FIQ_START uses in enable_fiq/disable_fiq.

Change-Id: I9bf8de403d06fec7597fd4652c78079fd4fa981b
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Rob Herring <rob.herring@calxeda.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: bc89663aa5c7ca620f58c34ab531ca409119becc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: update FIQ support for relocation of vectors

FIQ should no longer copy the FIQ code into the user visible vector
page.  Instead, it should use the hidden page.  This change makes
that happen.

Change-Id: Iec7716c43e2377fa3d66cc36ff8d141f58bfb6bf
Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: e39e3f3ebfef03450cf7bfa7a974a8c61f7980c8
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: allow kuser helpers to be removed from the vector page

Provide a kernel configuration option to allow the kernel user helpers
to be removed from the vector page, thereby preventing their use with
ROP (return orientated programming) attacks.  This option is only
visible for CPU architectures which natively support all the operations
which kernel user helpers would normally provide, and must be enabled
with caution.

Change-Id: Ic118b6951f4abca53ceb22b5a768ddad2ceb22b6
Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: f6f91b0d9fd971c630cef908dde8fe8795aefbf8
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: move signal handlers into a vdso-like page

Move the signal handlers into a VDSO page rather than keeping them in
the vectors page.  This allows us to place them randomly within this
page, and also map the page at a random location within userspace
further protecting these code fragments from ROP attacks.  The new
VDSO page is also poisoned in the same way as the vector page.

Change-Id: Ic45bb26efb1f00de0a025d36fc15dbd6580dc7de
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 48be69a026b2c17350a5ef18a1959a919f60be7d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: make vectors page inaccessible from userspace

If kuser helpers are not provided by the kernel, disable user access to
the vectors page.  With the kuser helpers gone, there is no reason for
this page to be visible to userspace.

Change-Id: Ia00a34e7952552634ccb03ee038cf3d0ead88459
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: a5463cd3435475386cbbe7b06e01292ac169d36f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: fix a cockup in 48be69a02 (ARM: move signal handlers into a vdso-like page)

Unfortunately, I never committed the fix to a nasty oops which can
occur as a result of that commit:

------------[ cut here ]------------
kernel BUG at /home/olof/work/batch/include/linux/mm.h:414!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 490 Comm: killall5 Not tainted 3.11.0-rc3-00288-gabe0308 #53
task: e90acac0 ti: e9be8000 task.ti: e9be8000
PC is at special_mapping_fault+0xa4/0xc4
LR is at __do_fault+0x68/0x48c

This doesn't show up unless you do quite a bit of testing; a simple
boot test does not do this, so all my nightly tests were passing fine.

The reason for this is that install_special_mapping() expects the
page array to stick around, and as this was only inserting one page
which was stored on the kernel stack, that's why this was blowing up.

Change-Id: Ib2cf8c19833e17d8d145e29141d68aaefd4dc233
Reported-by: Olof Johansson <olof@lixom.net>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: e0d407564b532d978b03ceccebd224a05d02f111
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: fix nommu builds with 48be69a02 (ARM: move signal handlers into a vdso-like page)

Olof reports that noMMU builds error out with:

arch/arm/kernel/signal.c: In function 'setup_return':
arch/arm/kernel/signal.c:413:25: error: 'mm_context_t' has no member named 'sigpage'

This shows one of the evilnesses of IS_ENABLED().  Get rid of it here
and replace it with #ifdef's - and as no noMMU platform can make use
of sigpage, depend on CONIFG_MMU not CONFIG_ARM_MPU.

Change-Id: I5875b23e7c076aeb8240081bd48a4c8516b612cb
Reported-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 8c0cc8a5d90bc7373a7a9e7f7a40eb41f51e03fc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[joonwoop@codeaurora.org: fixed merge conflict]
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: Fix the world famous typo with is_gate_vma()

Change-Id: I5fbbfbc2eb45276eaefeea5b839a7178ef9403e7
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 1d0bbf428924f94867542d49d436cf254b9dbd06
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: Fix FIQ code on VIVT CPUs

Aaro Koskinen reports the following oops:
Installing fiq handler from c001b110, length 0x164
Unable to handle kernel paging request at virtual address ffff1224
pgd = c0004000
[ffff1224] *pgd=00000000, *pte=11fff0cb, *ppte=11fff00a
...
[<c0013154>] (set_fiq_handler+0x0/0x6c) from [<c0365d38>] (ams_delta_init_fiq+0xa8/0x160)
 r6:00000164 r5:c001b110 r4:00000000 r3:fefecb4c
[<c0365c90>] (ams_delta_init_fiq+0x0/0x160) from [<c0365b14>] (ams_delta_init+0xd4/0x114)
 r6:00000000 r5:fffece10 r4:c037a9e0
[<c0365a40>] (ams_delta_init+0x0/0x114) from [<c03613b4>] (customize_machine+0x24/0x30)

This is because the vectors page is now write-protected, and to change
code in there we must write to its original alias.  Make that change,
and adjust the cache flushing such that the code will become visible
to the instruction stream on VIVT CPUs.

Change-Id: I316fd5088e72f68a2fb1e609c3f5774bac9162a0
Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 2ba85e7af4c639d933c9a87a6d7363f2983d5ada
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: 7819/1: fiq: Cast the first argument of flush_icache_range()

Commit 2ba85e7af4 (ARM: Fix FIQ code on VIVT CPUs) causes the following build warning:

arch/arm/kernel/fiq.c:92:3: warning: passing argument 1 of 'cpu_cache.coherent_kern_range' makes integer from pointer without a cast [enabled by default]

Cast it as '(unsigned long)base' to avoid the warning.

Change-Id: I6df03280ae8577e6a9dc85668fa1c4644e531b6c
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 7cb3be0a27805c625ff7cce20c53c926d9483243
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: 7816/1: CONFIG_KUSER_HELPERS: fix help text

Commit f6f91b0d9fd9 ("ARM: allow kuser helpers to be removed from the
vector page") introduced some help text for the CONFIG_KUSER_HELPERS
option which is rather contradictory.

Let's fix that, and improve it a little.

Change-Id: I9059789c8404556937c5f5d0fa15619f0ead6460
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: ac124504ecf6b20a2457d873d0728a8b991a5b0c
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-fixed: 561044
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
ARM: smp: Save CPU registers before IPI_CPU_STOP processing

When a kernel panic occurs on one CPU, other CPUs are instructed to stop
execution via the IPI_CPU_STOP message. These other CPUs dump their stack,
which may not be good enough to reconstruct their context to perform
post-mortem analysis. Dump each CPU's context
(before it started procesing the IPI) into a globally accessible structure
to allow for easier post-mortem debugging.

Change-Id: I68ac75f73d7ddaebaff9122b23e341bcb00e8fb9
Signed-off-by: Tingting Yang <tingting@codeaurora.org>
ARM: smp: fix incorrect per-cpu definition of regs_before_stop

The commit efd002896a3636a4d1606ac0630aaafbbfdea9aa introduced changes
to store CPU registers for all CPUs that handle IPI_CPU_STOP. The
structure to save the registers was intended to be a per-cpu variable.
However, the patch did not allocate a per-cpu structure and instead only
ended up providing a compiler per-cpu directive. Fix this bug by actually
defining a static per-cpu variable.

Change-Id: Ifd192223c135025897e10312f61b108757575068
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
ARM: 7880/1: Clear the IT state independent of the Thumb-2 mode

The ARM architecture reference specifies that the IT state bits in the
PSR must be all zeros in ARM mode or behavior is unspecified.  On the
Qualcomm Snapdragon S4/Krait architecture CPUs the processor continues
to consider the IT state bits while in ARM mode.  This makes it so
that some instructions are skipped by the CPU.

Signed-off-by: T.J. Purtell <tj@mobisocial.us>
[rmk+kernel@arm.linux.org.uk: fixed whitespace formatting in patch]
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Git-commit: 6ecf830e5029598732e04067e325d946097519cb
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
Change-Id: I74275a3d98aef291d6f41b1905acc3aeecb50b47
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
ARM: sched_clock: Load cycle count after epoch stabilizes

There is a small race between when the cycle count is read from
the hardware and when the epoch stabilizes. Consider this
scenario:

 CPU0                           CPU1
 ----                           ----
 cyc = read_sched_clock()
 cyc_to_sched_clock()
                                 update_sched_clock()
                                  ...
                                  cd.epoch_cyc = cyc;
  epoch_cyc = cd.epoch_cyc;
  ...
  epoch_ns + cyc_to_ns((cyc - epoch_cyc)

The cyc on cpu0 was read before the epoch changed. But we
calculate the nanoseconds based on the new epoch by subtracting
the new epoch from the old cycle count. Since epoch is most likely
larger than the old cycle count we calculate a large number that
will be converted to nanoseconds and added to epoch_ns, causing
time to jump forward too much.

Fix this problem by reading the hardware after the epoch has
stabilized.

Change-Id: I995133b229b2c2fedd5091406d1dc366d8bfff7b
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Git-commit: 336ae1180df5f69b9e0fb6561bec01c5f64361cf
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[sboyd: reworked for file movement kernel/time -> arm/kernel]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
ARM: Set CLK_EVT_FEAT_DYNIRQ flag memory mapped timers

Memory mapped timers are used as broadcast timers to wake up a core
across reset. CLK_EVT_FEAT_DYNIRQ ensures only the intended cores are
woken up instead of the default core that they are routed to, thereby
saving power.

Change-Id: I535faa0d1fd328fefe4422a6f362b17c94ab5b8e
Signed-off-by: Karthik Parsha <kparsha@codeaurora.org>
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>