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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-03 09:13:19 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-03 09:13:19 -0700 |
commit | 8546dc1d4b671480961c3eaf4c0c102ae6848340 (patch) | |
tree | c646079fb48811b22b742deb6bd2e907f9e6c3d4 /arch/arm/kernel/smp.c | |
parent | 9992ba72327fa0d8bdc9fb624e80f5cce338a711 (diff) | |
parent | 33b9f582c5c1db515412cc7efff28f7d1779321f (diff) | |
download | linux-8546dc1d4b671480961c3eaf4c0c102ae6848340.tar.bz2 |
Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm
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()
...
Diffstat (limited to 'arch/arm/kernel/smp.c')
-rw-r--r-- | arch/arm/kernel/smp.c | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 4619177bcfe6..47ab90563bf4 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -211,6 +211,13 @@ void __cpuinit __cpu_die(unsigned int cpu) } printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); + /* + * platform_cpu_kill() is generally expected to do the powering off + * and/or cutting of clocks to the dying CPU. Optionally, this may + * be done by the CPU which is dying in preference to supporting + * this call, but that means there is _no_ synchronisation between + * the requesting CPU and the dying CPU actually losing power. + */ if (!platform_cpu_kill(cpu)) printk("CPU%u: unable to kill\n", cpu); } @@ -230,14 +237,41 @@ void __ref cpu_die(void) idle_task_exit(); local_irq_disable(); - mb(); - /* Tell __cpu_die() that this CPU is now safe to dispose of */ + /* + * Flush the data out of the L1 cache for this CPU. This must be + * before the completion to ensure that data is safely written out + * before platform_cpu_kill() gets called - which may disable + * *this* CPU and power down its cache. + */ + flush_cache_louis(); + + /* + * Tell __cpu_die() that this CPU is now safe to dispose of. Once + * this returns, power and/or clocks can be removed at any point + * from this CPU and its cache by platform_cpu_kill(). + */ RCU_NONIDLE(complete(&cpu_died)); /* - * actual CPU shutdown procedure is at least platform (if not - * CPU) specific. + * Ensure that the cache lines associated with that completion are + * written out. This covers the case where _this_ CPU is doing the + * powering down, to ensure that the completion is visible to the + * CPU waiting for this one. + */ + flush_cache_louis(); + + /* + * The actual CPU shutdown procedure is at least platform (if not + * CPU) specific. This may remove power, or it may simply spin. + * + * Platforms are generally expected *NOT* to return from this call, + * although there are some which do because they have no way to + * power down the CPU. These platforms are the _only_ reason we + * have a return path which uses the fragment of assembly below. + * + * The return path should not be used for platforms which can + * power off the CPU. */ if (smp_ops.cpu_die) smp_ops.cpu_die(cpu); |