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linux/arch/arm/common/mcpm_platsmp.c

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ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
/*
* linux/arch/arm/mach-vexpress/mcpm_platsmp.c
*
* Created by: Nicolas Pitre, November 2012
* Copyright: (C) 2012-2013 Linaro Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Code to handle secondary CPU bringup and hotplug for the cluster power API.
*/
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <asm/mcpm.h>
#include <asm/smp.h>
#include <asm/smp_plat.h>
ARM: 7847/1: mcpm: Factor out logical-to-physical CPU translation This patch factors the logical-to-physical CPU translation out of mcpm_boot_secondary(), so that it can be reused elsewhere. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-02 02:57:28 +08:00
static void cpu_to_pcpu(unsigned int cpu,
unsigned int *pcpu, unsigned int *pcluster)
{
unsigned int mpidr;
mpidr = cpu_logical_map(cpu);
*pcpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
*pcluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
}
arm: delete __cpuinit/__CPUINIT usage from all ARM users 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>
2013-06-18 03:43:14 +08:00
static int mcpm_boot_secondary(unsigned int cpu, struct task_struct *idle)
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
{
ARM: 7847/1: mcpm: Factor out logical-to-physical CPU translation This patch factors the logical-to-physical CPU translation out of mcpm_boot_secondary(), so that it can be reused elsewhere. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-02 02:57:28 +08:00
unsigned int pcpu, pcluster, ret;
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
extern void secondary_startup(void);
ARM: 7847/1: mcpm: Factor out logical-to-physical CPU translation This patch factors the logical-to-physical CPU translation out of mcpm_boot_secondary(), so that it can be reused elsewhere. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-02 02:57:28 +08:00
cpu_to_pcpu(cpu, &pcpu, &pcluster);
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
pr_debug("%s: logical CPU %d is physical CPU %d cluster %d\n",
__func__, cpu, pcpu, pcluster);
mcpm_set_entry_vector(pcpu, pcluster, NULL);
ret = mcpm_cpu_power_up(pcpu, pcluster);
if (ret)
return ret;
mcpm_set_entry_vector(pcpu, pcluster, secondary_startup);
arch_send_wakeup_ipi_mask(cpumask_of(cpu));
dsb_sev();
return 0;
}
arm: delete __cpuinit/__CPUINIT usage from all ARM users 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>
2013-06-18 03:43:14 +08:00
static void mcpm_secondary_init(unsigned int cpu)
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
{
mcpm_cpu_powered_up();
}
#ifdef CONFIG_HOTPLUG_CPU
ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown CPU hotplug and kexec rely on smp_ops.cpu_kill(), which is supposed to wait for the CPU to park or power down, and perform the last rites (such as disabling clocks etc., where the platform doesn't do this automatically). kexec in particular is unsafe without performing this synchronisation to park secondaries. Without it, the secondaries might not be parked when kexec trashes the kernel. There is no generic way to do this synchronisation, so a new mcpm platform_ops method power_down_finish() is added by this patch. The new method is mandatory. A platform which provides no way to detect when CPUs are parked is likely broken. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-02 02:58:17 +08:00
static int mcpm_cpu_kill(unsigned int cpu)
{
unsigned int pcpu, pcluster;
cpu_to_pcpu(cpu, &pcpu, &pcluster);
ARM: 8029/1: mcpm: Rename the power_down_finish() functions to be less confusing The name "power_down_finish" seems to be causing some confusion, because it suggests that this function is responsible for taking some action to cause the specified CPU to complete its power down. This patch renames the affected functions to "wait_for_powerdown" and similar, since this function's intended purpose is just to wait for the hardware to finish a powerdown initiated by a previous cpu_power_down. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-04-17 23:58:39 +08:00
return !mcpm_wait_for_cpu_powerdown(pcpu, pcluster);
ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown CPU hotplug and kexec rely on smp_ops.cpu_kill(), which is supposed to wait for the CPU to park or power down, and perform the last rites (such as disabling clocks etc., where the platform doesn't do this automatically). kexec in particular is unsafe without performing this synchronisation to park secondaries. Without it, the secondaries might not be parked when kexec trashes the kernel. There is no generic way to do this synchronisation, so a new mcpm platform_ops method power_down_finish() is added by this patch. The new method is mandatory. A platform which provides no way to detect when CPUs are parked is likely broken. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-02 02:58:17 +08:00
}
ARM: 8392/3: smp: Only expose /sys/.../cpuX/online if hotpluggable Writes to /sys/.../cpuX/online fail if we determine the platform doesn't support hotplug for that CPU. Furthermore, if the cpu_die op isn't specified the system hangs when we try to offline a CPU and it comes right back online unexpectedly. Let's figure this stuff out before we make the sysfs nodes so that the online file doesn't even exist if it isn't (at least sometimes) possible to hotplug the CPU. Add a new 'cpu_can_disable' op and repoint all 'cpu_disable' implementations at it because all implementers use the op to indicate if a CPU can be hotplugged or not in a static fashion. With PSCI we may need to add a 'cpu_disable' op so that the secure OS can be migrated off the CPU we're trying to hotplug. In this case, the 'cpu_can_disable' op will indicate that all CPUs are hotpluggable by returning true, but the 'cpu_disable' op will make a PSCI migration call and occasionally fail, denying the hotplug of a CPU. This shouldn't be any worse than x86 where we may indicate that all CPUs are hotpluggable but occasionally we can't offline a CPU due to check_irq_vectors_for_cpu_disable() failing to find a CPU to move vectors to. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Nicolas Pitre <nico@linaro.org> Cc: Dave Martin <Dave.Martin@arm.com> Acked-by: Simon Horman <horms@verge.net.au> [shmobile portion] Tested-by: Simon Horman <horms@verge.net.au> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: <linux-sh@vger.kernel.org> Tested-by: Tyler Baker <tyler.baker@linaro.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-29 07:34:48 +08:00
static bool mcpm_cpu_can_disable(unsigned int cpu)
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
{
ARM: 8392/3: smp: Only expose /sys/.../cpuX/online if hotpluggable Writes to /sys/.../cpuX/online fail if we determine the platform doesn't support hotplug for that CPU. Furthermore, if the cpu_die op isn't specified the system hangs when we try to offline a CPU and it comes right back online unexpectedly. Let's figure this stuff out before we make the sysfs nodes so that the online file doesn't even exist if it isn't (at least sometimes) possible to hotplug the CPU. Add a new 'cpu_can_disable' op and repoint all 'cpu_disable' implementations at it because all implementers use the op to indicate if a CPU can be hotplugged or not in a static fashion. With PSCI we may need to add a 'cpu_disable' op so that the secure OS can be migrated off the CPU we're trying to hotplug. In this case, the 'cpu_can_disable' op will indicate that all CPUs are hotpluggable by returning true, but the 'cpu_disable' op will make a PSCI migration call and occasionally fail, denying the hotplug of a CPU. This shouldn't be any worse than x86 where we may indicate that all CPUs are hotpluggable but occasionally we can't offline a CPU due to check_irq_vectors_for_cpu_disable() failing to find a CPU to move vectors to. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Nicolas Pitre <nico@linaro.org> Cc: Dave Martin <Dave.Martin@arm.com> Acked-by: Simon Horman <horms@verge.net.au> [shmobile portion] Tested-by: Simon Horman <horms@verge.net.au> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: <linux-sh@vger.kernel.org> Tested-by: Tyler Baker <tyler.baker@linaro.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-29 07:34:48 +08:00
/* We assume all CPUs may be shut down. */
return true;
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
}
static void mcpm_cpu_die(unsigned int cpu)
{
unsigned int mpidr, pcpu, pcluster;
mpidr = read_cpuid_mpidr();
pcpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
pcluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
mcpm_set_entry_vector(pcpu, pcluster, NULL);
mcpm_cpu_power_down();
}
#endif
ARM: mcpm: provide an interface to set the SMP ops at run time This is cleaner than exporting the mcpm_smp_ops structure. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Jon Medhurst <tixy@linaro.org>
2013-04-09 13:29:17 +08:00
static struct smp_operations __initdata mcpm_smp_ops = {
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
.smp_boot_secondary = mcpm_boot_secondary,
.smp_secondary_init = mcpm_secondary_init,
#ifdef CONFIG_HOTPLUG_CPU
ARM: 7848/1: mcpm: Implement cpu_kill() to synchronise on powerdown CPU hotplug and kexec rely on smp_ops.cpu_kill(), which is supposed to wait for the CPU to park or power down, and perform the last rites (such as disabling clocks etc., where the platform doesn't do this automatically). kexec in particular is unsafe without performing this synchronisation to park secondaries. Without it, the secondaries might not be parked when kexec trashes the kernel. There is no generic way to do this synchronisation, so a new mcpm platform_ops method power_down_finish() is added by this patch. The new method is mandatory. A platform which provides no way to detect when CPUs are parked is likely broken. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-10-02 02:58:17 +08:00
.cpu_kill = mcpm_cpu_kill,
ARM: 8392/3: smp: Only expose /sys/.../cpuX/online if hotpluggable Writes to /sys/.../cpuX/online fail if we determine the platform doesn't support hotplug for that CPU. Furthermore, if the cpu_die op isn't specified the system hangs when we try to offline a CPU and it comes right back online unexpectedly. Let's figure this stuff out before we make the sysfs nodes so that the online file doesn't even exist if it isn't (at least sometimes) possible to hotplug the CPU. Add a new 'cpu_can_disable' op and repoint all 'cpu_disable' implementations at it because all implementers use the op to indicate if a CPU can be hotplugged or not in a static fashion. With PSCI we may need to add a 'cpu_disable' op so that the secure OS can be migrated off the CPU we're trying to hotplug. In this case, the 'cpu_can_disable' op will indicate that all CPUs are hotpluggable by returning true, but the 'cpu_disable' op will make a PSCI migration call and occasionally fail, denying the hotplug of a CPU. This shouldn't be any worse than x86 where we may indicate that all CPUs are hotpluggable but occasionally we can't offline a CPU due to check_irq_vectors_for_cpu_disable() failing to find a CPU to move vectors to. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Nicolas Pitre <nico@linaro.org> Cc: Dave Martin <Dave.Martin@arm.com> Acked-by: Simon Horman <horms@verge.net.au> [shmobile portion] Tested-by: Simon Horman <horms@verge.net.au> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: <linux-sh@vger.kernel.org> Tested-by: Tyler Baker <tyler.baker@linaro.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-07-29 07:34:48 +08:00
.cpu_can_disable = mcpm_cpu_can_disable,
ARM: mcpm: generic SMP secondary bringup and hotplug support 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 <nico@linaro.org> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Will Deacon <will.deacon@arm.com>
2012-11-20 05:02:17 +08:00
.cpu_die = mcpm_cpu_die,
#endif
};
ARM: mcpm: provide an interface to set the SMP ops at run time This is cleaner than exporting the mcpm_smp_ops structure. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Jon Medhurst <tixy@linaro.org>
2013-04-09 13:29:17 +08:00
void __init mcpm_smp_set_ops(void)
{
smp_set_ops(&mcpm_smp_ops);
}
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