Tools such as kexec and CPU hotplug require a way to reset the processor
and branch to some code in physical space. This requires various bits of
jiggery pokery with the caches and MMU which, when it goes wrong, tends
to lock up the system.

This patch fleshes out the soft_restart implementation so that it
branches to the reset code using the identity mapping. This requires us
to change to a temporary stack, held within the kernel image as a static
array, to avoid conflicting with the new view of memory.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The DFSR and IFSR register format is different when LPAE is enabled. In
addition, DFSR and IFSR have similar definitions for the fault type.
This modifies the fault code to correctly handle the new format.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds the MMU initialisation for the LPAE page table format.
The swapper_pg_dir size with LPAE is 5 rather than 4 pages. A new
proc-v7-3level.S file contains the TTB initialisation, context switch
and PTE setting code with the LPAE. The TTBRx split is based on the
PAGE_OFFSET with TTBR1 used for the kernel mappings. The 36-bit mappings
(supersections) and a few other memory types in mmu.c are conditionally
compiled.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Before we enable the MMU, we must ensure that the TTBR registers contain
sane values. After the MMU has been enabled, we jump to the *virtual*
address of the following function, so we also need to ensure that the
SCTLR write has taken effect.

This patch adds ISB instructions around the SCTLR write to ensure the
visibility of the above.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

The ARM SMP booting code allocates a temporary set of page tables
containing an identity mapping of the kernel image and provides this
to secondary CPUs for initial booting.

In reality, we only need to include the __turn_mmu_on function in the
identity mapping since the rest of the kernel is executing from virtual
addresses after this point.

This patch adds __turn_mmu_on to the .idmap.text section, allowing the
SMP booting code to use the idmap_pgd directly and not have to populate
its own set of page table.

As a result of this patch, we can make the identity_mapping_add function
static (since it is only used within mm/idmap.c) and also remove the
identity_mapping_del function. The identity map population is moved to
an early initcall so that it is setup in time for secondary CPU bringup.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

__create_page_tables identity maps the region of memory from
__enable_mmu to the end of __turn_mmu_on.

In preparation for including __turn_mmu_on in the .idmap.text section,
this patch modifies the identity mapping so that it only includes the
__turn_mmu_on code.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The ARM CPU suspend code requires cpu_resume_mmu to be identity mapped
in order to re-enable the MMU when coming out of suspend. Currently,
this is accomplished by maintaining a suspend_pgd with the relevant
mapping put in place at init time.

This patch replaces the use of suspend_pgd with the new idmap_pgd.
cpu_resume_mmu is placed in the .idmap.text section so that it is
included in the identity map.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NDave Martin <dave.martin@linaro.org>
Tested-by: NLorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

When disabling and re-enabling the MMU, it is necessary to take out an
identity mapping for the code that manipulates the SCTLR in order to
avoid it disappearing from under our feet. This is useful when soft
rebooting and returning from CPU suspend.

This patch allocates a set of page tables during boot and populates them
with an identity mapping for the .idmap.text section. This means that
users of the identity map do not need to manage their own pgd and can
instead annotate their functions with __idmap or, in the case of assembly
code, place them in the correct section.
Acked-by: NDave Martin <dave.martin@linaro.org>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Tested-by: NLorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch introduces .enable_irq and .disable_irq into
struct arm_pmu_platdata, so platform specific irq enablement
can be handled after request_irq, and platform specific irq
disablement can be handled before free_irq.

This patch is for support of  pmu irq routed from CTI on omap4.
Acked-by: NJean Pihet <j-pihet@ti.com>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

armpmu_get_max_events is only called from perf_num_counters, so we can
inline it there. It existed as a separate entity as a hangover from
the original perf-based oprofile implementation.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Commit 8f622422 ("perf events: Add generic front-end and back-end
stalled cycle event definitions") added two new ABI events for counting
stalled cycles.

This patch adds support for these new events to the ARM perf
implementation.

Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Jean Pihet <j-pihet@ti.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch updates the ARMv7 perf event numbers so that:

(1) A consistent naming scheme is used between different CPUs.

(2) Only events actually used by Linux are described.

(3) Where possible, architected events are used in preference to
    CPU-specific events.

This results in the removal of a load of unused, hardcoded data and
makes it more clear as to which events are supported on each PMU.

Cc: Jean Pihet <j-pihet@ti.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

kernel/sched.c:7354:2: warning: initialization from incompatible pointer type

Align cpu_coregroup_mask prototype interface with sched_domain_mask_f typedef
use int cpu instead of unsigned int cpu

Cc: <stable@vger.kernel.org>
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The SWP instruction is deprecated on ARMv6 and with ARMv7 it will be
UNDEFINED when CONFIG_SWP_EMULATE is selected. In this case, probing a
SWP instruction will cause an oops when the kprobes emulation code
executes an undefined instruction.

As the SWP instruction should be rare or non-existent in kernels for
ARMv6 and later, we can simply avoid these problems by not allowing
probing of these.
Reported-by: NLeif Lindholm <leif.lindholm@arm.com>
Tested-by: NLeif Lindholm <leif.lindholm@arm.com>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

There is a kprobes testcase for the instruction "strd r2, [r3], r4".
This has unpredictable behaviour as it uses r3 for register writeback
addressing and also stores it to memory.

On a cortex A9, this testcase would fail because the instruction writes
the updated value of r3 to memory, whereas the kprobes emulation code
writes the original value.

Fix this by changing testcase to used r5 instead of r3.
Reported-by: NLeif Lindholm <leif.lindholm@arm.com>
Tested-by: NLeif Lindholm <leif.lindholm@arm.com>
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

When compiling kprobes-test-thumb.c an error like below may occur:

/tmp/ccKcuJcG.s:19179: Error: offset out of range

This is caused by the compiler underestimating the size of the inline
assembler instructions containing ".space 0x1000" and failing to spill
the literal pool in time to prevent the generation of PC relative load
instruction with invalid offsets.

The fix implemented by this patch is to replace a single large .space
directive by a number of 4 byte .space's. This requires splitting the
macros which generate test cases for branch instructions into two forms:
one with, and one without support for inserting extra code between
branch and target.
Acked-by: NNicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: NJon Medhurst <jon.medhurst@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix compilation failure, when Thumb support is not enabled:

arch/arm/kernel/entry-armv.S: Assembler messages:
arch/arm/kernel/entry-armv.S:501: Error: backward ref to unknown label "2:"
arch/arm/kernel/entry-armv.S:502: Error: backward ref to unknown label "3:"
make[2]: *** [arch/arm/kernel/entry-armv.o] Error 1
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Attempting to use a hardware counter on a platform with a supported PMU
but where the platform_device (defining the interrupts) has not been
registered results in a NULL pointer dereference.

This patch fixes the problem by checking that we actually have a platform
device registered before attempting to grab the interrupts.
Reported-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch implements a workaround for PL310 erratum 769419. On
revisions of the PL310 prior to r3p2, the Store Buffer does not
automatically drain. This can cause normal, non-cacheable writes to be
retained when the memory system is idle, leading to suboptimal I/O
performance for drivers using coherent DMA.

This patch adds an optional wmb() call to the cpu_idle loop. On systems
with an outer cache, this causes an explicit flush of the store buffer.

Cc: stable@vger.kernel.org
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Tested-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We only need to set the system up for a soft-restart if we're going to
be doing a soft-restart.  Provide a new function (soft_restart()) which
does the setup and final call for this, and make platforms use it.
Eliminate the call to setup_restart() from the default handler.

This means that platforms arch_reset() function is no longer called with
the page tables prepared for a soft-restart, and caches will still be
enabled.
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NKukjin Kim <kgene.kim@samsung.com>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Acked-by: NViresh Kumar <viresh.kumar@st.com>
Acked-by: NKrzysztof Ha■asa <khc@pm.waw.pl>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NRichard Purdie <richard.purdie@linuxfoundation.org>
Acked-by: NWan ZongShun <mcuos.com@gmail.com>
Acked-by: NEric Miao <eric.y.miao@gmail.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The meminfo array has to be sorted before sanity_check_meminfo() in
arch/arm/mm/mmu.c is called for it to work properly.  This also allows
for a simpler find_limits() in arch/arm/mm/init.c.

The sort is moved to arch/arm/kernel/setup.c because that's where the
meminfo array is populated.  Eventually this should be improved upon
to make the memory bank parser a bit more robust against problems
such as overlapping memory ranges.
Signed-off-by: NNicolas Pitre <nicolas.pitre@linaro.org>

These two syscalls were introduced during the last merge window.
Add the entries into the ARM call tables for them.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

When validating an event group, we call pmu->get_event_idx for each
group member in order to check that the group can be scheduled as a
unit on an empty PMU.

As a result of 3fc2c830 ("ARM: perf: remove event limit from
pmu_hw_events"), the used_mask member of struct cpu_hw_events must be
setup explicitly, something which we don't do for the fake cpu_hw_events
used for validation.

This patch sets up an empty used_mask for the fake validation
cpu_hw_events, preventing NULL deferences when trying to get the event
index.
Reported-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Commit b0e89590 ("ARM: PMU: move CPU PMU platform device handling and
init into perf") inadvertently removed the EXPORT_SYMBOL_GPL on
release_pmu, so out-of-tree modules can no longer play nice with perf,
even if they tried in the first place.

This patch re-exports the symbol.
Reported-by: NJon Medhurst (Tixy) <jon.medhurst@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Even when CONFIG_MULTI_IRQ_HANDLER is selected, the core code
requires the arch_irq_handler_default macro to be defined as
a fallback.

It turns out nobody is using that particular feature as both PXA
and shmobile have all their machine descriptors populated with
the interrupt handler, leaving unused code (or empty macros) in
their entry-macro.S file just to be able to compile entry-armv.S.

Make CONFIG_MULTI_IRQ_HANDLER exclusive wrt arch_irq_handler_default,
which allows to remove one test from the hot path. Also cleanup both
PXA and shmobile entry-macro.S.

Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NEric Miao <eric.y.miao@gmail.com>
Tested-by: NJamie Iles <jamie@jamieiles.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

setup_processor copies the arch_name and elf_name fields out of the
selected proc_info_list into two fixed size buffers.

Since the proc_info_list structure is defined in a proc_*.S assembly
file, this can lead to subtle errors if the strings defined there are
too long (for example, corrupting the machine ID).

This patch uses snprintf instead of sprintf to ensure that these buffers
are not overrun.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

setup_mm_for_reboot() doesn't make use of its argument, so remove it.
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Move the failure to reboot into machine_restart() to always catch
this condition, even if a platform decides to hook the restarting
via arm_pm_restart().
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Change 'soft_reboot' into a more generic 'restart_mode' variable,
allowing the default restart mode to be specified.
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add a restart hook to the machine_desc record so we don't have to
populate all platforms with init_early methods to initialize the
arm_pm_restart function pointer.
Acked-by: NNicolas Pitre <nico@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Recent gcc versions generate unaligned accesses by default on ARMv6 and
later processors. This patch ensures that the SCTLR.A bit is always
cleared on such processors to avoid kernel traping before
alignment_init() is called.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Tested-by: NJohn Linn <John.Linn@xilinx.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This reverts commit 2b034922.

Will Deacon reports:

This is causing kexec to fail.

The symptoms are that the .init.text section is not loaded as part of the
new kernel image, so when we try to do the SMP/UP fixups we hit a whole sea
of poison left there by the previous kernel.

So my guess is that machine_kexec_prepare *is* too early for preparing the
reboot_code_buffer and, unless anybody has a good reason not to, I'd like to
revert the patch causing these problems.
Reported-by: NWill Deacon <will.deacon@arm.com>

These files will fail to compile if we dont clean them up in advance
and have them include the appropriate headers they need.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Many of the core ARM kernel files are not modules, but just
including module.h for exporting symbols.  Now these files can
use the lighter footprint export.h for this role.

There are probably lots more, but ARM files of mach-* and plat-*
don't get coverage via a simple yesconfig build.  They will have
to be cleaned up and tested via using their respective configs.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Building these files does not reveal a hidden need for
any of these.  Since module.h brings in the whole kitchen
sink, it just needlessly adds 30k+ lines to the cpp burden.

There are probably lots more, but ARM files of mach-* and plat-*
don't get coverage via a simple yesconfig build.  They will have
to be cleaned up and tested via using their respective configs.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

To fix things like this:

arch/arm/mach-omap2/usb-tusb6010.c:58: error: implicit declaration of function 'memset'
arch/arm/kernel/leds.c:40: error: implicit declaration of function 'strcspn'
arch/arm/kernel/leds.c:40: warning: incompatible implicit declaration of built-in function 'strcspn'
arch/arm/kernel/leds.c:45: error: implicit declaration of function 'strncmp'
arch/arm/kernel/leds.c:55: error: implicit declaration of function 'strlen'
arch/arm/kernel/leds.c:55: warning: incompatible implicit declaration of built-in function 'strlen'
arch/arm/mach-omap2/clockdomain.c:52: error: implicit declaration of function 'strcmp'
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

It was implicitly getting it via an implicit presence of module.h
but when we clean that up, we'll get a bunch of lines like this:

arch/arm/kernel/ptrace.c:764: error: 'NT_PRSTATUS' undeclared here (not in a function)
arch/arm/kernel/ptrace.c:765: error: 'ELF_NGREG' undeclared here (not in a function)
arch/arm/kernel/ptrace.c:776: error: 'NT_PRFPREG' undeclared here (not in a function)
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

The problem is related to the early enabling of interrupts and the
per cpu timer setup before the cpu is marked online. This doesn't
need to be done in order to call calibrate_delay().

calibrate_delay() monitors jiffies, which are updated from the CPU
which is waiting for the new CPU to set the online bit.

So simply calibrate_delay() can be called on the new CPU just from
the interrupt disabled region and move the local timer setup after
stored the cpu data and before enabling interrupts.

This solves both the cpu_online vs. cpu_active problem and the
affinity setting of the per cpu timers.
Signed-off-by: NThomas Gleinxer <tglx@linutronix.de>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch remove the hardcoded link between local timers and PPIs,
and convert the PPI users (TWD, MCT and MSM timers) to the new
*_percpu_irq interface. Also some collateral cleanup
(local_timer_ack() is gone, and the interrupt handler is strictly
private to each driver).

PPIs are now useable for more than just the local timers.

Additional testing by David Brown (msm8250 and msm8660) and
Shawn Guo (imx6q).

Cc: David Brown <davidb@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

PPI handling is a bit of an odd beast. It uses its own low level
handling code and is hardwired to the local timers (hence lacking
a registration interface).

Instead, switch the low handling to the normal SPI handling code.
PPIs are handled by the handle_percpu_devid_irq flow.

This also allows the removal of some duplicated code.

Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: David Brown <davidb@codeaurora.org>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NDavid Brown <davidb@codeaurora.org>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>