linux.git/arch/arm/kernel/smp.c, branch v3.11 Linux kernel source tree ARM: 7807/1: kexec: validate CPU hotplug support 2013-08-13T19:23:18+00:00 Stephen Warren swarren@nvidia.com 2013-08-02T19:52:49+00:00 2103f6cba61a8b8bea3fc1b63661d830a2125e76 Architectures should fully validate whether kexec is possible as part of machine_kexec_prepare(), so that user-space's kexec_load() operation can report any problems. Performing validation in machine_kexec() itself is too late, since it is not allowed to return. Prior to this patch, ARM's machine_kexec() was testing after-the-fact whether machine_kexec_prepare() was able to disable all but one CPU. Instead, modify machine_kexec_prepare() to validate all conditions necessary for machine_kexec_prepare()'s to succeed. BUG if the validation succeeded, yet disabling the CPUs didn't actually work. Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Architectures should fully validate whether kexec is possible as part of
machine_kexec_prepare(), so that user-space's kexec_load() operation can
report any problems. Performing validation in machine_kexec() itself is
too late, since it is not allowed to return.

Prior to this patch, ARM's machine_kexec() was testing after-the-fact
whether machine_kexec_prepare() was able to disable all but one CPU.
Instead, modify machine_kexec_prepare() to validate all conditions
necessary for machine_kexec_prepare()'s to succeed. BUG if the validation
succeeded, yet disabling the CPUs didn't actually work.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
arm: delete __cpuinit/__CPUINIT usage from all ARM users 2013-07-14T23:36:52+00:00 Paul Gortmaker paul.gortmaker@windriver.com 2013-06-17T19:43:14+00:00 8bd26e3a7e49af2697449bbcb7187a39dc85d672 The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. Note that some harmless section mismatch warnings may result, since notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) and are flagged as __cpuinit -- so if we remove the __cpuinit from the arch specific callers, we will also get section mismatch warnings. As an intermediate step, we intend to turn the linux/init.h cpuinit related content into no-ops as early as possible, since that will get rid of these warnings. In any case, they are temporary and harmless. This removes all the ARM uses of the __cpuinit macros from C code, and all __CPUINIT from assembly code. It also had two ".previous" section statements that were paired off against __CPUINIT (aka .section ".cpuinit.text") that also get removed here. [1] https://lkml.org/lkml/2013/5/20/589 Cc: Russell King <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> 
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
and are flagged as __cpuinit  -- so if we remove the __cpuinit from
the arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
related content into no-ops as early as possible, since that will get
rid of these warnings.  In any case, they are temporary and harmless.

This removes all the ARM uses of the __cpuinit macros from C code,
and all __CPUINIT from assembly code.  It also had two ".previous"
section statements that were paired off against __CPUINIT
(aka .section ".cpuinit.text") that also get removed here.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Merge branch 'devel-stable' into for-next 2013-06-29T10:44:43+00:00 Russell King rmk+kernel@arm.linux.org.uk 2013-06-29T10:44:43+00:00 3c0c01ab742ddfaf6b6f2d64b890e77cda4b7727 Conflicts: arch/arm/Makefile arch/arm/include/asm/glue-proc.h 
Conflicts:
	arch/arm/Makefile
	arch/arm/include/asm/glue-proc.h
Merge branch 'for-rmk/lpae' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable 2013-06-18T19:11:32+00:00 Russell King rmk+kernel@arm.linux.org.uk 2013-06-18T19:11:32+00:00 3fbd55ec21e698221ffb43526090137b07c32586 Conflicts: arch/arm/kernel/smp.c Please pull these miscellaneous LPAE fixes I've been collecting for a while now for 3.11. They've been tested and reviewed by quite a few people, and most of the patches are pretty trivial. -- Will Deacon. 
Conflicts:
	arch/arm/kernel/smp.c

Please pull these miscellaneous LPAE fixes I've been collecting for a while
now for 3.11. They've been tested and reviewed by quite a few people, and most
of the patches are pretty trivial. -- Will Deacon.
ARM: 7759/1: decouple CPU offlining from reboot/shutdown 2013-06-17T20:35:25+00:00 Stephen Warren swarren@nvidia.com 2013-06-14T15:14:14+00:00 19ab428f4b7988ef3ac727c680efc193ef53ce14 Add comments to machine_shutdown()/halt()/power_off()/restart() that describe their purpose and/or requirements re: CPUs being active/not. In machine_shutdown(), replace the call to smp_send_stop() with a call to disable_nonboot_cpus(). This completely disables all but one CPU, thus satisfying the requirement that only a single CPU be active for kexec. Adjust Kconfig dependencies for this change. In machine_halt()/power_off()/restart(), call smp_send_stop() directly, rather than via machine_shutdown(); these functions don't need to completely de-activate all CPUs using hotplug, but rather just quiesce them. Remove smp_kill_cpus(), and its call from smp_send_stop(). smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling smp_ops.cpu_die() on the target CPUs first. At least some implementations of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra, for example. Since smp_send_stop() is only used for shutdown, halt, and power-off, there is no need to attempt any kind of CPU hotplug here. Adjust Kconfig to reflect that machine_shutdown() (and hence kexec) relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee that hotplug will work, or even that hotplug is implemented for a particular piece of HW that a multi-platform zImage runs on. Hence, add error-checking to machine_kexec() to determine whether it did work. Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Stephen Warren <swarren@nvidia.com> Acked-by: Will Deacon <will.deacon@arm.com> Tested-by: Zhangfei Gao <zhangfei.gao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Add comments to machine_shutdown()/halt()/power_off()/restart() that
describe their purpose and/or requirements re: CPUs being active/not.

In machine_shutdown(), replace the call to smp_send_stop() with a call to
disable_nonboot_cpus(). This completely disables all but one CPU, thus
satisfying the requirement that only a single CPU be active for kexec.
Adjust Kconfig dependencies for this change.

In machine_halt()/power_off()/restart(), call smp_send_stop() directly,
rather than via machine_shutdown(); these functions don't need to
completely de-activate all CPUs using hotplug, but rather just quiesce
them.

Remove smp_kill_cpus(), and its call from smp_send_stop().
smp_kill_cpus() was indirectly calling smp_ops.cpu_kill() without calling
smp_ops.cpu_die() on the target CPUs first. At least some implementations
of smp_ops had issues with this; it caused cpu_kill() to hang on Tegra,
for example. Since smp_send_stop() is only used for shutdown, halt, and
power-off, there is no need to attempt any kind of CPU hotplug here.

Adjust Kconfig to reflect that machine_shutdown() (and hence kexec)
relies upon disable_nonboot_cpus(). However, this alone doesn't guarantee
that hotplug will work, or even that hotplug is implemented for a
particular piece of HW that a multi-platform zImage runs on. Hence, add
error-checking to machine_kexec() to determine whether it did work.

Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by:  Zhangfei Gao <zhangfei.gao@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: mpu: add MPU initialisation for secondary cores 2013-06-07T16:02:53+00:00 Jonathan Austin jonathan.austin@arm.com 2013-02-22T18:51:30+00:00 eb08375ea66e63c5e11dea69b43c5633d531ce81 The MPU initialisation on the primary core is performed in two stages, one minimal stage to ensure the CPU can boot and a second one after sanity_check_meminfo. As the memory configuration is known by the time we boot secondary cores only a single step is necessary, provided the values for DRSR are passed to secondaries. This patch implements this arrangement. The configuration generated for the MPU regions is made available to the secondary core, which can then use the asm MPU intialisation code to program a complete region configuration. This is necessary for SMP configurations without an MMU, as the MPU initialisation is the only way to ensure that memory is specified as 'shared'. Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> CC: Nicolas Pitre <nico@linaro.org> 
The MPU initialisation on the primary core is performed in two stages, one
minimal stage to ensure the CPU can boot and a second one after
sanity_check_meminfo. As the memory configuration is known by the time we
boot secondary cores only a single step is necessary, provided the values
for DRSR are passed to secondaries.

This patch implements this arrangement. The configuration generated for the
MPU regions is made available to the secondary core, which can then use the
asm MPU intialisation code to program a complete region configuration.

This is necessary for SMP configurations without an MMU, as the MPU
initialisation is the only way to ensure that memory is specified as
'shared'.

Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
CC: Nicolas Pitre <nico@linaro.org>
ARM: nommu: do not initialise page tables in secondary_data structure 2013-06-07T16:02:43+00:00 Will Deacon will.deacon@arm.com 2012-02-28T13:02:59+00:00 c4a1f032ed35d744e3d74b8aebe8d85f29aecd88 nommu systems do not require any page tables, so don't try to initialise them when bringing up secondary cores. Signed-off-by: Will Deacon <will.deacon@arm.com> 
nommu systems do not require any page tables, so don't try to initialise
them when bringing up secondary cores.

Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: LPAE: accomodate >32-bit addresses for page table base 2013-05-30T15:02:15+00:00 Cyril Chemparathy cyril@ti.com 2012-07-21T19:55:04+00:00 4756dcbfd37819a8359d3c69a22be2ee41666d0f This patch redefines the early boot time use of the R4 register to steal a few low order bits (ARCH_PGD_SHIFT bits) on LPAE systems. This allows for up to 38-bit physical addresses. Signed-off-by: Cyril Chemparathy <cyril@ti.com> Signed-off-by: Vitaly Andrianov <vitalya@ti.com> Acked-by: Nicolas Pitre <nico@linaro.org> Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Subash Patel <subash.rp@samsung.com> Signed-off-by: Will Deacon <will.deacon@arm.com> 
This patch redefines the early boot time use of the R4 register to steal a few
low order bits (ARCH_PGD_SHIFT bits) on LPAE systems.  This allows for up to
38-bit physical addresses.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Subash Patel <subash.rp@samsung.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM: smp: Drop RCU_NONIDLE usage in cpu_die() 2013-05-21T15:56:21+00:00 Stephen Boyd sboyd@codeaurora.org 2013-05-21T00:57:16+00:00 aa033810461ee56abbef6cef10aabd6b97f5caee Before f7b861b7a6d9 ("arm: Use generic idle loop") ARM would kill the CPU within the rcu idle section. Now that the rcu_idle_enter()/exit() pair have been pushed lower down in the idle loop this is no longer true and so using RCU_NONIDLE here is no longer necessary and also harmful because RCU is not actually idle at this point. Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Before f7b861b7a6d9 ("arm: Use generic idle loop") ARM would kill the
CPU within the rcu idle section.  Now that the rcu_idle_enter()/exit()
pair have been pushed lower down in the idle loop this is no longer true
and so using RCU_NONIDLE here is no longer necessary and also harmful
because RCU is not actually idle at this point.

Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2013-05-03T16:13:19+00:00 Linus Torvalds torvalds@linux-foundation.org 2013-05-03T16:13:19+00:00 8546dc1d4b671480961c3eaf4c0c102ae6848340 Pull ARM updates from Russell King: "The major items included in here are: - MCPM, multi-cluster power management, part of the infrastructure required for ARMs big.LITTLE support. - A rework of the ARM KVM code to allow re-use by ARM64. - Error handling cleanups of the IS_ERR_OR_NULL() madness and fixes of that stuff for arch/arm - Preparatory patches for Cortex-M3 support from Uwe Kleine-König. There is also a set of three patches in here from Hugh/Catalin to address freeing of inappropriate page tables on LPAE. You already have these from akpm, but they were already part of my tree at the time he sent them, so unfortunately they'll end up with duplicate commits" * 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (77 commits) ARM: EXYNOS: remove unnecessary use of IS_ERR_VALUE() ARM: IMX: remove unnecessary use of IS_ERR_VALUE() ARM: OMAP: use consistent error checking ARM: cleanup: OMAP hwmod error checking ARM: 7709/1: mcpm: Add explicit AFLAGS to support v6/v7 multiplatform kernels ARM: 7700/2: Make cpu_init() notrace ARM: 7702/1: Set the page table freeing ceiling to TASK_SIZE ARM: 7701/1: mm: Allow arch code to control the user page table ceiling ARM: 7703/1: Disable preemption in broadcast_tlb*_a15_erratum() ARM: mcpm: provide an interface to set the SMP ops at run time ARM: mcpm: generic SMP secondary bringup and hotplug support ARM: mcpm_head.S: vlock-based first man election ARM: mcpm: Add baremetal voting mutexes ARM: mcpm: introduce helpers for platform coherency exit/setup ARM: mcpm: introduce the CPU/cluster power API ARM: multi-cluster PM: secondary kernel entry code ARM: cacheflush: add synchronization helpers for mixed cache state accesses ARM: cpu hotplug: remove majority of cache flushing from platforms ARM: smp: flush L1 cache in cpu_die() ARM: tegra: remove tegra specific cpu_disable() ... 
Pull ARM updates from Russell King:
 "The major items included in here are:

   - MCPM, multi-cluster power management, part of the infrastructure
     required for ARMs big.LITTLE support.

   - A rework of the ARM KVM code to allow re-use by ARM64.

   - Error handling cleanups of the IS_ERR_OR_NULL() madness and fixes
     of that stuff for arch/arm

   - Preparatory patches for Cortex-M3 support from Uwe Kleine-König.

  There is also a set of three patches in here from Hugh/Catalin to
  address freeing of inappropriate page tables on LPAE.  You already
  have these from akpm, but they were already part of my tree at the
  time he sent them, so unfortunately they'll end up with duplicate
  commits"

* 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (77 commits)
  ARM: EXYNOS: remove unnecessary use of IS_ERR_VALUE()
  ARM: IMX: remove unnecessary use of IS_ERR_VALUE()
  ARM: OMAP: use consistent error checking
  ARM: cleanup: OMAP hwmod error checking
  ARM: 7709/1: mcpm: Add explicit AFLAGS to support v6/v7 multiplatform kernels
  ARM: 7700/2: Make cpu_init() notrace
  ARM: 7702/1: Set the page table freeing ceiling to TASK_SIZE
  ARM: 7701/1: mm: Allow arch code to control the user page table ceiling
  ARM: 7703/1: Disable preemption in broadcast_tlb*_a15_erratum()
  ARM: mcpm: provide an interface to set the SMP ops at run time
  ARM: mcpm: generic SMP secondary bringup and hotplug support
  ARM: mcpm_head.S: vlock-based first man election
  ARM: mcpm: Add baremetal voting mutexes
  ARM: mcpm: introduce helpers for platform coherency exit/setup
  ARM: mcpm: introduce the CPU/cluster power API
  ARM: multi-cluster PM: secondary kernel entry code
  ARM: cacheflush: add synchronization helpers for mixed cache state accesses
  ARM: cpu hotplug: remove majority of cache flushing from platforms
  ARM: smp: flush L1 cache in cpu_die()
  ARM: tegra: remove tegra specific cpu_disable()
  ...