linux-stable.git/arch/arm/kernel/smp.c, branch linux-3.3.y

ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd

2012-05-12T16:32:17+00:00

commit fde165b2a29673aabf18ceff14dea1f1cfb0daad upstream.

Commit 4e8ee7de227e3ab9a72040b448ad728c5428a042 (ARM: SMP: use
idmap_pgd for mapping MMU enable during secondary booting)
switched secondary boot to use idmap_pgd, which is initialized
during early_initcall, instead of a page table initialized during
__cpu_up.  This causes idmap_pgd to contain the static mappings
but be missing all dynamic mappings.

If a console is registered that creates a dynamic mapping, the
printk in secondary_start_kernel will trigger a data abort on
the missing mapping before the exception handlers have been
initialized, leading to a hang.  Initial boot is not affected
because no consoles have been registered, and resume is usually
not affected because the offending console is suspended.
Onlining a cpu with hotplug triggers the problem.

A workaround is to the printk in secondary_start_kernel until
after the page tables have been switched back to init_mm.

Signed-off-by: Colin Cross 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP

2012-01-23T10:20:05+00:00

It turns out that the logical CPU mapping is useful even when !CONFIG_SMP
for manipulation of devices like interrupt and power controllers when
running a UP kernel on a CPU other than 0. This can happen when kexecing
a UP image from an SMP kernel.

In the future, multi-cluster systems running AMP configurations will
require something similar for mapping cluster IDs, so it makes sense to
decouple this logic in preparation for this support.

Acked-by: Yang Bai 
Acked-by: Marc Zyngier 
Reported-by: Joerg Roedel 
Signed-off-by: Will Deacon 
Signed-off-by: Russell King

ARM: fix rcu stalls on SMP platforms

2012-01-19T17:26:30+00:00

We can stall RCU processing on SMP platforms if a CPU sits in its idle
loop for a long time.  This happens because we don't call irq_enter()
and irq_exit() around generic_smp_call_function_interrupt() and
friends.  Add the necessary calls, and remove the one from within
ipi_timer(), so that they're all in a common place.

Signed-off-by: Russell King

ARM: stop: execute platform callback from cpu_stop code

2011-12-12T16:07:35+00:00

Sending IPI_CPU_STOP to a CPU causes it to execute a busy cpu_relax
loop forever. This makes it impossible to kexec successfully on an SMP
system since the secondary CPUs do not reset.

This patch adds a callback to platform_cpu_kill, defined when
CONFIG_HOTPLUG_CPU=y, from the ipi_cpu_stop handling code. This function
currently just returns 1 on all platforms that define it but allows them
to do something more sophisticated in the future.

Signed-off-by: Will Deacon

ARM: SMP: use idmap_pgd for mapping MMU enable during secondary booting

2011-12-06T14:04:15+00:00

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: Catalin Marinas 
Signed-off-by: Will Deacon

ARM: idmap: populate identity map pgd at init time using .init.text

2011-12-06T14:04:14+00:00

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: Dave Martin 
Reviewed-by: Catalin Marinas 
Tested-by: Lorenzo Pieralisi 
Signed-off-by: Will Deacon

Merge branch 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm

2011-10-28T19:02:27+00:00

* 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm: (178 commits)
  ARM: 7139/1: fix compilation with CONFIG_ARM_ATAG_DTB_COMPAT and large TEXT_OFFSET
  ARM: gic, local timers: use the request_percpu_irq() interface
  ARM: gic: consolidate PPI handling
  ARM: switch from NO_MACH_MEMORY_H to NEED_MACH_MEMORY_H
  ARM: mach-s5p64x0: remove mach/memory.h
  ARM: mach-s3c64xx: remove mach/memory.h
  ARM: plat-mxc: remove mach/memory.h
  ARM: mach-prima2: remove mach/memory.h
  ARM: mach-zynq: remove mach/memory.h
  ARM: mach-bcmring: remove mach/memory.h
  ARM: mach-davinci: remove mach/memory.h
  ARM: mach-pxa: remove mach/memory.h
  ARM: mach-ixp4xx: remove mach/memory.h
  ARM: mach-h720x: remove mach/memory.h
  ARM: mach-vt8500: remove mach/memory.h
  ARM: mach-s5pc100: remove mach/memory.h
  ARM: mach-tegra: remove mach/memory.h
  ARM: plat-tcc: remove mach/memory.h
  ARM: mach-mmp: remove mach/memory.h
  ARM: mach-cns3xxx: remove mach/memory.h
  ...

Fix up mostly pretty trivial conflicts in:
 - arch/arm/Kconfig
 - arch/arm/include/asm/localtimer.h
 - arch/arm/kernel/Makefile
 - arch/arm/mach-shmobile/board-ap4evb.c
 - arch/arm/mach-u300/core.c
 - arch/arm/mm/dma-mapping.c
 - arch/arm/mm/proc-v7.S
 - arch/arm/plat-omap/Kconfig
largely due to some CONFIG option renaming (ie CONFIG_PM_SLEEP ->
CONFIG_ARM_CPU_SUSPEND for the arm-specific suspend code etc) and
addition of NEED_MACH_MEMORY_H next to HAVE_IDE.

Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2011-10-26T14:17:32+00:00

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  rtmutex: Add missing rcu_read_unlock() in debug_rt_mutex_print_deadlock()
  lockdep: Comment all warnings
  lib: atomic64: Change the type of local lock to raw_spinlock_t
  locking, lib/atomic64: Annotate atomic64_lock::lock as raw
  locking, x86, iommu: Annotate qi->q_lock as raw
  locking, x86, iommu: Annotate irq_2_ir_lock as raw
  locking, x86, iommu: Annotate iommu->register_lock as raw
  locking, dma, ipu: Annotate bank_lock as raw
  locking, ARM: Annotate low level hw locks as raw
  locking, drivers/dca: Annotate dca_lock as raw
  locking, powerpc: Annotate uic->lock as raw
  locking, x86: mce: Annotate cmci_discover_lock as raw
  locking, ACPI: Annotate c3_lock as raw
  locking, oprofile: Annotate oprofilefs lock as raw
  locking, video: Annotate vga console lock as raw
  locking, latencytop: Annotate latency_lock as raw
  locking, timer_stats: Annotate table_lock as raw
  locking, rwsem: Annotate inner lock as raw
  locking, semaphores: Annotate inner lock as raw
  locking, sched: Annotate thread_group_cputimer as raw
  ...

Fix up conflicts in kernel/posix-cpu-timers.c manually: making
cputimer->cputime a raw lock conflicted with the ABBA fix in commit
bcd5cff7216f ("cputimer: Cure lock inversion").

Merge branch 'misc' into for-linus

2011-10-25T07:19:59+00:00

Conflicts:
	arch/arm/mach-integrator/integrator_ap.c

ARM: 7133/1: SMP: fix per cpu timer setup before the cpu is marked online

2011-10-23T20:22:58+00:00

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: Thomas Gleinxer 
Signed-off-by: Kukjin Kim 
Signed-off-by: Russell King