linux-toradex.git/arch/arm/common/Makefile, branch v4.1.5

ARM: 7962/2: Make all mcpm functions notrace

2014-02-18T19:39:33+00:00

The functions in mcpm_entry.c are mostly intended for use during
scary cache and coherency disabling sequences, or do other things
which confuse trace ... like powering a CPU down and not
returning. Similarly for the backend code.

For simplicity, this patch just makes whole files notrace.
There should be more than enough traceable points on the paths to
these functions, but we can be more fine-grained later if there is
a need for it.

Jon Medhurst:
Also added spc.o to the list of files as it contains functions used by
MCPM code which have comments comments like: "might be used in code
paths where normal cacheable locks are not working"

Signed-off-by: Dave Martin 
Signed-off-by: Jon Medhurst 
Acked-by: Nicolas Pitre 
Signed-off-by: Russell King

Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm

2013-11-13T23:51:29+00:00

Pull ARM updates from Russell King:
"Included in this series are:

1. BE8 (modern big endian) changes for ARM from Ben Dooks
2. big.Little support from Nicolas Pitre and Dave Martin
3. support for LPAE systems with all system memory above 4GB
4. Perf updates from Will Deacon
5. Additional prefetching and other performance improvements from Will.
6. Neon-optimised AES implementation fro Ard.
7. A number of smaller fixes scattered around the place.

There is a rather horrid merge conflict in tools/perf - I was never
notified of the conflict because it originally occurred between Will's
tree and other stuff. Consequently I have a resolution which Will
forwarded me, which I'll forward on immediately after sending this
mail.

The other notable thing is I'm expecting some build breakage in the
crypto stuff on ARM only with Ard's AES patches. These were merged
into a stable git branch which others had already pulled, so there's
little I can do about this. The problem is caused because these
patches have a dependency on some code in the crypto git tree - I
tried requesting a branch I can pull to resolve these, and all I got
each time from the crypto people was "we'll revert our patches then"
which would only make things worse since I still don't have the
dependent patches. I've no idea what's going on there or how to
resolve that, and since I can't split these patches from the rest of
this pull request, I'm rather stuck with pushing this as-is or
reverting Ard's patches.

Since it should "come out in the wash" I've left them in - the only
build problems they seem to cause at the moment are with randconfigs,
and since it's a new feature anyway. However, if by -rc1 the
dependencies aren't in, I think it'd be best to revert Ard's patches"

I resolved the perf conflict roughly as per the patch sent by Russell,
but there may be some differences. Any errors are likely mine. Let's
see how the crypto issues work out..

* 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (110 commits)
ARM: 7868/1: arm/arm64: remove atomic_clear_mask() in "include/asm/atomic.h"
ARM: 7867/1: include: asm: use 'int' instead of 'unsigned long' for 'oldval' in atomic_cmpxchg().
ARM: 7866/1: include: asm: use 'long long' instead of 'u64' within atomic.h
ARM: 7871/1: amba: Extend number of IRQS
ARM: 7887/1: Don't smp_cross_call() on UP devices in arch_irq_work_raise()
ARM: 7872/1: Support arch_irq_work_raise() via self IPIs
ARM: 7880/1: Clear the IT state independent of the Thumb-2 mode
ARM: 7878/1: nommu: Implement dummy early_paging_init()
ARM: 7876/1: clear Thumb-2 IT state on exception handling
ARM: 7874/2: bL_switcher: Remove cpu_hotplug_driver_{lock,unlock}()
ARM: footbridge: fix build warnings for netwinder
ARM: 7873/1: vfp: clear vfp_current_hw_state for dying cpu
ARM: fix misplaced arch_virt_to_idmap()
ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown
ARM: 7847/1: mcpm: Factor out logical-to-physical CPU translation
ARM: 7869/1: remove unused XSCALE_PMU Kconfig param
ARM: 7864/1: Handle 64-bit memory in case of 32-bit phys_addr_t
ARM: 7863/1: Let arm_add_memory() always use 64-bit arguments
ARM: 7862/1: pcpu: replace __get_cpu_var_uses
ARM: 7861/1: cacheflush: consolidate single-CPU ARMv7 cache disabling code
...

ARM: delete mach-shark

2013-09-17T10:34:36+00:00

The Shark machine sub-architecture (also known as DNARD, the
DIGITAL Network Appliance Reference Design) lacks a maintainer
able to apply and test patches to modernize the architecture.

It is suspected that the current kernel, while it compiles,
does not even boot on this machine. The listed maintainer has
expressed that he will not be able to spend any time on the
maintenance for the coming year.

So let's delete it from the kernel for now. It can always be
resurrected with git revert if maintenance is resumed.

As the VIA82c505 PCI adapter was only used by this
architecture, that gets deleted too.

Cc: arm@kernel.org
Cc: Alexander Schulz 
Signed-off-by: Linus Walleij

ARM: bL_switcher: add a simple /dev user interface for debugging purposes

2013-08-05T04:13:00+00:00

Only the basic call to aid debugging.

*** NOT FOR PRODUCTION ***

Usage:

	echo , > /dev/b.L_switcher

where  is the logical CPU number, and  is 0 for the
first cluster and 1 for the second cluster.

Signed-off-by: nicolas Pitre

ARM: b.L: core switcher code

2013-07-30T13:02:13+00:00

This is the core code implementing big.LITTLE switcher functionality.
Rationale for this code is available here:

http://lwn.net/Articles/481055/

The main entry point for a switch request is:

void bL_switch_request(unsigned int cpu, unsigned int new_cluster_id)

If the calling CPU is not the wanted one, this wrapper takes care of
sending the request to the appropriate CPU with schedule_work_on().

At the moment the core switch operation is handled by bL_switch_to()
which must be called on the CPU for which a switch is requested.

What this code does:

  * Return early if the current cluster is the wanted one.

  * Close the gate in the kernel entry vector for both the inbound
    and outbound CPUs.

  * Wake up the inbound CPU so it can perform its reset sequence in
    parallel up to the kernel entry vector gate.

  * Migrate all interrupts in the GIC targeting the outbound CPU
    interface to the inbound CPU interface, including SGIs. This is
    performed by gic_migrate_target() in drivers/irqchip/irq-gic.c.

  * Call cpu_pm_enter() which takes care of flushing the VFP state to
    RAM and save the CPU interface config from the GIC to RAM.

  * Modify the cpu_logical_map to refer to the inbound physical CPU.

  * Call cpu_suspend() which saves the CPU state (general purpose
    registers, page table address) onto the stack and store the
    resulting stack pointer in an array indexed by the updated
    cpu_logical_map, then call the provided shutdown function.
    This happens in arch/arm/kernel/sleep.S.

At this point, the provided shutdown function executed by the outbound
CPU ungates the inbound CPU. Therefore the inbound CPU:

  * Picks up the saved stack pointer in the array indexed by its MPIDR
    in arch/arm/kernel/sleep.S.

  * The MMU and caches are re-enabled using the saved state on the
    provided stack, just like if this was a resume operation from a
    suspended state.

  * Then cpu_suspend() returns, although this is on the inbound CPU
    rather than the outbound CPU which called it initially.

  * The function cpu_pm_exit() is called which effect is to restore the
    CPU interface state in the GIC using the state previously saved by
    the outbound CPU.

  * Exit of bL_switch_to() to resume normal kernel execution on the
    new CPU.

However, the outbound CPU is potentially still running in parallel while
the inbound CPU is resuming normal kernel execution, hence we need
per CPU stack isolation to execute bL_do_switch().  After the outbound
CPU has ungated the inbound CPU, it calls mcpm_cpu_power_down() to:

  * Clean its L1 cache.

  * If it is the last CPU still alive in its cluster (last man standing),
    it also cleans its L2 cache and disables cache snooping from the other
    cluster.

  * Power down the CPU (or whole cluster).

Code called from bL_do_switch() might end up referencing 'current' for
some reasons.  However, 'current' is derived from the stack pointer.
With any arbitrary stack, the returned value for 'current' and any
dereferenced values through it are just random garbage which may lead to
segmentation faults.

The active page table during the execution of bL_do_switch() is also a
problem.  There is no guarantee that the inbound CPU won't destroy the
corresponding task which would free the attached page table while the
outbound CPU is still running and relying on it.

To solve both issues, we borrow some of the task space belonging to
the init/idle task which, by its nature, is lightly used and therefore
is unlikely to clash with our usage.  The init task is also never going
away.

Right now the logical CPU number is assumed to be equivalent to the
physical CPU number within each cluster. The kernel should also be
booted with only one cluster active.  These limitations will be lifted
eventually.

Signed-off-by: Nicolas Pitre

ARM: davinci: move private EDMA API to arm/common

2013-06-18T05:22:03+00:00

Move mach-davinci/dma.c to common/edma.c so it can be used
by OMAP (specifically AM33xx) as well.

Signed-off-by: Matt Porter 
Acked-by: Chris Ball  # davinci_mmc.c
Acked-by: Mark Brown 
Acked-by: Olof Johansson 
[nsekhar@ti.com: dropped davinci sffsdr changes]
Signed-off-by: Sekhar Nori

Merge tag 'firmware-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

2013-05-04T19:33:36+00:00

Pull ARM platform specific firmware interfaces from Olof Johansson:
 "Two platforms, bcm and exynos have their own firmware interfaces using
  the "secure monitor call", this adds support for those.

  We had originally planned to have a third set of patches in here,
  which would extend support for the existing generic "psci" call that
  is used on multiple platforms as well as Xen and KVM guests, but that
  ended up getting dropped because the patches were not ready in time."

* tag 'firmware-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: bcm: mark bcm_kona_smc_init as __init
  ARM: bcm281xx: Add DT support for SMC handler
  ARM: bcm281xx: Add L2 cache enable code
  ARM: EXYNOS: Add secure firmware support to secondary CPU bring-up
  ARM: EXYNOS: Add IO mapping for non-secure SYSRAM.
  ARM: EXYNOS: Add support for Exynos secure firmware
  ARM: EXYNOS: Add support for secure monitor calls
  ARM: Add interface for registering and calling firmware-specific operations

ARM: 7709/1: mcpm: Add explicit AFLAGS to support v6/v7 multiplatform kernels

2013-05-02T11:14:34+00:00

The full mcpm layer is not likely to be relevant to v6 based
platforms, so a multiplatform kernel won't use that code if booted
on v6 hardware.

This patch modifies the AFLAGS for affected mcpm .S files to
specify armv7-a explicitly for that code.

Signed-off-by: Dave Martin 
Acked-by: Arnd Bergmann 
Acked-by: Nicolas Pitre 
Signed-off-by: Russell King

ARM: mcpm: generic SMP secondary bringup and hotplug support

2013-04-24T14:37:02+00:00

Now that the cluster power API is in place, we can use it for SMP secondary
bringup and CPU hotplug in a generic fashion.

Signed-off-by: Nicolas Pitre 
Reviewed-by: Santosh Shilimkar 
Reviewed-by: Will Deacon

ARM: mcpm_head.S: vlock-based first man election

2013-04-24T14:37:01+00:00

Instead of requiring the first man to be elected in advance (which
can be suboptimal in some situations), this patch uses a per-
cluster mutex to co-ordinate selection of the first man.

This should also make it more feasible to reuse this code path for
asynchronous cluster resume (as in CPUidle scenarios).

We must ensure that the vlock data doesn't share a cacheline with
anything else, or dirty cache eviction could corrupt it.

Signed-off-by: Dave Martin 
Signed-off-by: Nicolas Pitre 
Reviewed-by: Santosh Shilimkar 
Reviewed-by: Will Deacon