There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).

Move them to the admin guide.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: NAlexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

The Kdump documentation describes procedures with admins use
in order to solve issues on their systems.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Converts ARM the text files to ReST, preparing them to be an
architecture book.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by Corentin Labbe <clabbe.montjoie@gmail.com> # For sun4i-ss

We only support the generic GUP now, so rename the config option to
be more clear, and always use the mm/Kconfig definition of the
symbol and select it from the arch Kconfigs.

Link: http://lkml.kernel.org/r/20190625143715.1689-11-hch@lst.deSigned-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKhalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: NJason Gunthorpe <jgg@mellanox.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: James Hogan <jhogan@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "remove ARCH_SELECT_MEMORY_MODEL where it has no effect".

For several architectures the ARCH_SELECT_MEMORY_MODEL has no real effect
because the dependencies for the memory model are always evaluated to a
single value.

Remove the ARCH_SELECT_MEMORY_MODEL from the Kconfigs for these
architectures.

This patch (of 3):

The ARCH_SELECT_MEMORY_MODEL in arch/arm/Kconfig is enabled only when
ARCH_SPARSEMEM_ENABLE=y.  But in this case, ARCH_SPARSEMEM_DEFAULT is also
enabled and this in turn enables SPARSEMEM_MANUAL.

Since there is no definition of ARCH_FLATMEM_ENABLE in arch/arm/Kconfig,
SPARSEMEM_MANUAL is the only enabled memory model, hence the final
selection will evaluate to SPARSEMEM=y.

Since ARCH_SPARSEMEM_ENABLE is set to 'y' only by several sub-arch
configurations, the default for must sub-arches would be the falback to
FLATMEM regardless of ARCH_SELECT_MEMORY_MODEL.

Link: http://lkml.kernel.org/r/1556740577-4140-2-git-send-email-rppt@linux.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert sa1100 to use the common clock framework.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Allow architectures to opt into ARCH_HAS_BINFMT_FLAT support instead of
assuming that all nommu ports support the format.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: NGreg Ungerer <gerg@linux-m68k.org>

This will eventually allow us to kill the need for an <asm/flat.h> for
many cases.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NVladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: NVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: NGreg Ungerer <gerg@linux-m68k.org>

The v7 ARM states that all cache and branch predictor maintenance operations
that do not specify an address execute, relative to each other, in program
order. However, because of this erratum, an L2 set/way cache maintenance
operation can overtake an L1 set/way cache maintenance operation, this would
cause the data corruption.

This ERRATA affected the Cortex-A7 and present in r0p2, r0p3, r0p4, r0p5.

This patch is the SW workaround by adding a DSB before changing cache levels as
the ARM ERRATA: ARM/MP: 814220 told in the ARM ERRATA documentation.
Signed-off-by: NJason Liu <r64343@freescale.com>
Signed-off-by: NBenjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

This adds support for working around errata A12 857271 / A17 857272.
These errata were causing hangs on rk3288-based Chromebooks and it was
confirmed that this workaround fixed the problems.  In the Chrome OS
3.14 kernel this was treated as two errata: ERRATA_FOOBAR [1] and
ERRATA_CR711784 [2].  Apparently the two errata got lumped together at
some point in time.

Let's actually get the workaround landed.

[1] https://crrev.com/c/342753
[2] https://crbug.com/711784Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Signed-off-by: NSonny Rao <sonnyrao@chromium.org>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Convert kdump documentation to ReST and add it to the
user faced manual, as the documents are mainly focused on
sysadmins that would be enabling kdump.

Note: the vmcoreinfo.rst has one very long title on one of its
sub-sections:

	PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask|PAGE_BUDDY_MAPCOUNT_VALUE(~PG_buddy)|PAGE_OFFLINE_MAPCOUNT_VALUE(~PG_offline)

I opted to break this one, into two entries with the same content,
in order to make it easier to display after being parsed in html and PDF.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

There's no reason why we can't enable chained scatterlist for RiscPC,
we already support chained scatterlists in the IOMD DMA support code.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Mostly due to x86 and acpi conversion, several documentation
links are still pointing to the old file. Fix them.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: NWolfram Sang <wsa@the-dreams.de>
Reviewed-by: NSven Van Asbroeck <TheSven73@gmail.com>
Reviewed-by: NBhupesh Sharma <bhsharma@redhat.com>
Acked-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

After discussing with the subarch maintainers and Hilscher,
we concluded that the netx subarchitecture (Netx 100/500)
is no longer maintained or tested, and noone will miss it
if we delete it. So delete it.

There is a newer Netx 4000 architecture which we may see
included at some point, but this will be supported using
the standard multiplatform and devicetree mechanisms and is
easier to develop from scratch.

Cc: Michael Trensch <MTrensch@hilscher.com>
Acked-By: NRobert Schwebel <r.schwebel@pengutronix.de>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Most architectures do not need the memblock memory after the page
allocator is initialized, but only few enable ARCH_DISCARD_MEMBLOCK in the
arch Kconfig.

Replacing ARCH_DISCARD_MEMBLOCK with ARCH_KEEP_MEMBLOCK and inverting the
logic makes it clear which architectures actually use memblock after
system initialization and skips the necessity to add ARCH_DISCARD_MEMBLOCK
to the architectures that are still missing that option.

Link: http://lkml.kernel.org/r/1556102150-32517-1-git-send-email-rppt@linux.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

No need to handle the freeing disable in arch code when we already have a
core hook (and a different name for the option) for it.

Link: http://lkml.kernel.org/r/20190213174621.29297-7-hch@lst.deSigned-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Acked-by: NMike Rapoport <rppt@linux.ibm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Steven Price <steven.price@arm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the old gettimeoffset() interface (which became buggy in
several ways) with a clocksource that atomically reads the count
and status from the timer, and corrects the count as appropriate
ensuring proper resolution of time without time warping backwards.

We keep the original periodic timer non-clock event implementation
to provide the kernel with a regular source of interrupts, which
are required to keep the clocksource properly updated.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Naresh Kamboju recently reported that the function-graph tracer crashes
on ARM. The function-graph tracer assumes that the kernel is built with
frame pointers.

We explicitly disabled the function-graph tracer when building Thumb2,
since the Thumb2 ABI doesn't have frame pointers.

We recently changed the way the unwinder method was selected, which
seems to have made it more likely that we can end up with the function-
graph tracer enabled but without the kernel built with frame pointers.

Fix up the function graph tracer dependencies so the option is not
available when we have no possibility of having frame pointers, and
adjust the dependencies on the unwinder option to hide the non-frame
pointer unwinder options if the function-graph tracer is enabled.
Reviewed-by: NMasami Hiramatsu <mhiramat@kernel.org>
Tested-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

This augments the IXP4xx to select and use the new
timer driver in drivers/clocksource and removes the old
code in the machine.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This deletes the old irq+gpiochip combo from the IXP4xx
machine and switches it over to use the new drivers merged
in respective subsystem.

Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This localizes the <mach/irqs.h> header to the mach-ixp4xx
directory, removes NR_IRQS and switches IXP4xx over to using
SPARSE_IRQ.

This is a prerequisite for DT support.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This rewrites the IXP4xx to use MULTI_IRQ_HANDLER and
create an irqdomain for the irqchip in the platform. We
convert the timer to request the interrupt like any other
driver in the process.

We bump all IRQs to 16+offset to avoid using IRQ 0 and
set NR_IRQS to 512 (the default for most systems).
This conveniently fits with the first 16 IRQs being
pre-allocated when using SPARSE_IRQ.

This is a prerequisite for SPARSE_IRQ and DT boot.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Move the Trusted Foundations support out of arch/arm/firmware and into
drivers/firmware where most other firmware support implementations are
located.
Signed-off-by: NThierry Reding <treding@nvidia.com>

Currently, we have two different implementation of rwsem:

 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c)
 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c)

As we are going to use a single generic implementation for rwsem-xadd.c
and no architecture-specific code will be needed, there is no point
in keeping two different implementations of rwsem. In most cases, the
performance of rwsem-spinlock.c will be worse. It also doesn't get all
the performance tuning and optimizations that had been implemented in
rwsem-xadd.c over the years.

For simplication, we are going to remove rwsem-spinlock.c and make all
architectures use a single implementation of rwsem - rwsem-xadd.c.

All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM
in the code are removed.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NWaiman Long <longman@redhat.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: nios2-dev@lists.rocketboards.org
Cc: openrisc@lists.librecores.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Link: https://lkml.kernel.org/r/20190322143008.21313-3-longman@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

allnoconfig build with just ARCH_DAVINCI enabled
fails because drivers/clk/davinci/* depends on
REGMAP being enabled.

Fix it by selecting REGMAP_MMIO when building in
DaVinci support.
Signed-off-by: NSekhar Nori <nsekhar@ti.com>
Reviewed-by: NDavid Lechner <david@lechnology.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

This adds the basic M10V SoC support under arch/arm.
Since all cores are activated in the custom bootloader before booting
linux, it is necessary to wait for the secondary-cores using cpu-enable-
method and special sram.
Signed-off-by: NSugaya Taichi <sugaya.taichi@socionext.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

This API is primarily used through DT entries, but two architectures
and two drivers call it directly.  So instead of selecting the config
symbol for random architectures pull it in implicitly for the actual
users.  Also rename the Kconfig option to describe the feature better.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS
Acked-by: NLee Jones <lee.jones@linaro.org>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Everything is in place now for SPARSE_IRQ. Select it and set
DAVINCI_INTC_START to NR_IRQS.

We now need to include mach/irqs.h in a couple places as it is no
longer indirectly included after selecting SPARSE_IRQ.
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: NDavid Lechner <david@lechnology.com>
Signed-off-by: NSekhar Nori <nsekhar@ti.com>

In order to support SPARSE_IRQ we first need to make davinci use the
generic irq handler for ARM. Translate the legacy assembly to C and
put the irq handlers into their respective drivers (aintc and cp-intc).
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NSekhar Nori <nsekhar@ti.com>

All new 32-bit architectures should have 64-bit userspace off_t type, but
existing architectures has 32-bit ones.

To enforce the rule, new config option is added to arch/Kconfig that defaults
ARCH_32BIT_OFF_T to be disabled for new 32-bit architectures. All existing
32-bit architectures enable it explicitly.

New option affects force_o_largefile() behaviour. Namely, if userspace
off_t is 64-bits long, we have no reason to reject user to open big files.

Note that even if architectures has only 64-bit off_t in the kernel
(arc, c6x, h8300, hexagon, nios2, openrisc, and unicore32),
a libc may use 32-bit off_t, and therefore want to limit the file size
to 4GB unless specified differently in the open flags.
Signed-off-by: NYury Norov <ynorov@caviumnetworks.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NYury Norov <ynorov@marvell.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

The OF_RESERVED_MEM can be used if we have either CMA or the generic
declare coherent code built and we support the early flattened DT.

So don't bother making it a user visible options that is selected
by most configs that fit the above category, but just select it when
the requirements are met.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NRob Herring <robh@kernel.org>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS
Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64

Arm TC2 fails cpu hotplug stress test.

This issue was tracked down to a missing copy of the new affinity
cpumask for the vexpress-spc interrupt into struct
irq_common_data.affinity when the interrupt is migrated in
migrate_one_irq().

Fix it by replacing the arm specific hotplug cpu migration with the
generic irq code.

This is the counterpart implementation to commit 217d453d ("arm64:
fix a migrating irq bug when hotplug cpu").

Tested with cpu hotplug stress test on Arm TC2 (multi_v7_defconfig plus
CONFIG_ARM_BIG_LITTLE_CPUFREQ=y and CONFIG_ARM_VEXPRESS_SPC_CPUFREQ=y).
The vexpress-spc interrupt (irq=22) on this board is affine to CPU0.
Its affinity cpumask now changes correctly e.g. from 0 to 1-4 when
CPU0 is hotplugged out.
Suggested-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NDietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

As of commit 7484c727 ("ARM: realview: delete the RealView board
files"), the ARM Timer and Watchdog Unit is instantiated from DT only.
Moreover, the driver is selected from ARCH_MULTIPLATFORM platforms only,
which implies OF, TIMER_OF, and COMMON_CLK.

Hence remove all unused legacy infrastructure from the driver.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

According to the ARM Cortex-A5 and Cortex-A9 Technical Reference
Manuals, SCU stands for "Snoop Control Unit".
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

Introduce ARCH_RDA and mach-rda for RDA Micro SoCs.
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NOlof Johansson <olof@lixom.net>

The Kconfig lexer supports special characters such as '.' and '/' in
the parameter context. In my understanding, the reason is just to
support bare file paths in the source statement.

I do not see a good reason to complicate Kconfig for the room of
ambiguity.

The majority of code already surrounds file paths with double quotes,
and it makes sense since file paths are constant string literals.

Make it treewide consistent now.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NIngo Molnar <mingo@kernel.org>

All architectures except for sparc64 use the dma-direct code in some
form, and even for sparc64 we had the discussion of a direct mapping
mode a while ago.  In preparation for directly calling the direct
mapping code don't bother having it optionally but always build the
code in.  This is a minor hardship for some powerpc and arm configs
that don't pull it in yet (although they should in a relase ot two),
and sparc64 which currently doesn't need it at all, but it will
reduce the ifdef mess we'd otherwise need significantly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Tested-by: NJesper Dangaard Brouer <brouer@redhat.com>
Tested-by: NTony Luck <tony.luck@intel.com>

On ARM, we currently only change the value of the stack canary when
switching tasks if the kernel was built for UP. On SMP kernels, this
is impossible since the stack canary value is obtained via a global
symbol reference, which means
a) all running tasks on all CPUs must use the same value
b) we can only modify the value when no kernel stack frames are live
   on any CPU, which is effectively never.

So instead, use a GCC plugin to add a RTL pass that replaces each
reference to the address of the __stack_chk_guard symbol with an
expression that produces the address of the 'stack_canary' field
that is added to struct thread_info. This way, each task will use
its own randomized value.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Laura Abbott <labbott@redhat.com>
Cc: kernel-hardening@lists.openwall.com
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NKees Cook <keescook@chromium.org>