2013-01-02 23:24:22 +08:00
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/*
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* Spin Table SMP initialisation
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*
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* Copyright (C) 2013 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for
some systems where we can't bring CPUs online individually and must hold
multiple CPUs in a safe area until the kernel is able to handle them.
The current SMP infrastructure for arm64 is closely coupled to this
holding pen, and alternative boot methods must launch CPUs into the pen,
where they sit before they are launched into the kernel proper.
With PSCI (and possibly other future boot methods), we can bring CPUs
online individually, and need not perform the secondary_holding_pen
dance. Instead, this patch factors the holding pen management code out
to the spin-table boot method code, as it is the only boot method
requiring the pen.
A new entry point for secondaries, secondary_entry is added for other
boot methods to use, which bypasses the holding pen and its associated
overhead when bringing CPUs online. The smp.pen.text section is also
removed, as the pen can live in head.text without problem.
The cpu_operations structure is extended with two new functions,
cpu_boot and cpu_postboot, for bringing a cpu into the kernel and
performing any post-boot cleanup required by a bootmethod (e.g.
resetting the secondary_holding_pen_release to INVALID_HWID).
Documentation is added for cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-10-25 03:30:16 +08:00
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#include <linux/delay.h>
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2013-01-02 23:24:22 +08:00
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/smp.h>
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#include <asm/cacheflush.h>
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2013-10-25 03:30:15 +08:00
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#include <asm/cpu_ops.h>
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arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for
some systems where we can't bring CPUs online individually and must hold
multiple CPUs in a safe area until the kernel is able to handle them.
The current SMP infrastructure for arm64 is closely coupled to this
holding pen, and alternative boot methods must launch CPUs into the pen,
where they sit before they are launched into the kernel proper.
With PSCI (and possibly other future boot methods), we can bring CPUs
online individually, and need not perform the secondary_holding_pen
dance. Instead, this patch factors the holding pen management code out
to the spin-table boot method code, as it is the only boot method
requiring the pen.
A new entry point for secondaries, secondary_entry is added for other
boot methods to use, which bypasses the holding pen and its associated
overhead when bringing CPUs online. The smp.pen.text section is also
removed, as the pen can live in head.text without problem.
The cpu_operations structure is extended with two new functions,
cpu_boot and cpu_postboot, for bringing a cpu into the kernel and
performing any post-boot cleanup required by a bootmethod (e.g.
resetting the secondary_holding_pen_release to INVALID_HWID).
Documentation is added for cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-10-25 03:30:16 +08:00
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#include <asm/cputype.h>
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#include <asm/smp_plat.h>
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extern void secondary_holding_pen(void);
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volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
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2013-01-02 23:24:22 +08:00
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static phys_addr_t cpu_release_addr[NR_CPUS];
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arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for
some systems where we can't bring CPUs online individually and must hold
multiple CPUs in a safe area until the kernel is able to handle them.
The current SMP infrastructure for arm64 is closely coupled to this
holding pen, and alternative boot methods must launch CPUs into the pen,
where they sit before they are launched into the kernel proper.
With PSCI (and possibly other future boot methods), we can bring CPUs
online individually, and need not perform the secondary_holding_pen
dance. Instead, this patch factors the holding pen management code out
to the spin-table boot method code, as it is the only boot method
requiring the pen.
A new entry point for secondaries, secondary_entry is added for other
boot methods to use, which bypasses the holding pen and its associated
overhead when bringing CPUs online. The smp.pen.text section is also
removed, as the pen can live in head.text without problem.
The cpu_operations structure is extended with two new functions,
cpu_boot and cpu_postboot, for bringing a cpu into the kernel and
performing any post-boot cleanup required by a bootmethod (e.g.
resetting the secondary_holding_pen_release to INVALID_HWID).
Documentation is added for cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-10-25 03:30:16 +08:00
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static DEFINE_RAW_SPINLOCK(boot_lock);
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/*
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* Write secondary_holding_pen_release in a way that is guaranteed to be
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* visible to all observers, irrespective of whether they're taking part
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* in coherency or not. This is necessary for the hotplug code to work
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* reliably.
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*/
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static void write_pen_release(u64 val)
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{
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void *start = (void *)&secondary_holding_pen_release;
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unsigned long size = sizeof(secondary_holding_pen_release);
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secondary_holding_pen_release = val;
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__flush_dcache_area(start, size);
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}
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2013-01-02 23:24:22 +08:00
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2013-10-25 03:30:15 +08:00
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static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu)
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2013-01-02 23:24:22 +08:00
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{
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/*
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* Determine the address from which the CPU is polling.
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*/
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if (of_property_read_u64(dn, "cpu-release-addr",
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&cpu_release_addr[cpu])) {
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pr_err("CPU %d: missing or invalid cpu-release-addr property\n",
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cpu);
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return -1;
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}
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return 0;
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}
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2013-10-25 03:30:15 +08:00
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static int smp_spin_table_cpu_prepare(unsigned int cpu)
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2013-01-02 23:24:22 +08:00
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{
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void **release_addr;
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if (!cpu_release_addr[cpu])
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return -ENODEV;
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release_addr = __va(cpu_release_addr[cpu]);
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2013-10-11 21:52:18 +08:00
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/*
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* We write the release address as LE regardless of the native
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* endianess of the kernel. Therefore, any boot-loaders that
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* read this address need to convert this address to the
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* boot-loader's endianess before jumping. This is mandated by
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* the boot protocol.
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*/
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release_addr[0] = (void *) cpu_to_le64(__pa(secondary_holding_pen));
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2013-01-02 23:24:22 +08:00
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__flush_dcache_area(release_addr, sizeof(release_addr[0]));
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/*
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* Send an event to wake up the secondary CPU.
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*/
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sev();
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return 0;
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}
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arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for
some systems where we can't bring CPUs online individually and must hold
multiple CPUs in a safe area until the kernel is able to handle them.
The current SMP infrastructure for arm64 is closely coupled to this
holding pen, and alternative boot methods must launch CPUs into the pen,
where they sit before they are launched into the kernel proper.
With PSCI (and possibly other future boot methods), we can bring CPUs
online individually, and need not perform the secondary_holding_pen
dance. Instead, this patch factors the holding pen management code out
to the spin-table boot method code, as it is the only boot method
requiring the pen.
A new entry point for secondaries, secondary_entry is added for other
boot methods to use, which bypasses the holding pen and its associated
overhead when bringing CPUs online. The smp.pen.text section is also
removed, as the pen can live in head.text without problem.
The cpu_operations structure is extended with two new functions,
cpu_boot and cpu_postboot, for bringing a cpu into the kernel and
performing any post-boot cleanup required by a bootmethod (e.g.
resetting the secondary_holding_pen_release to INVALID_HWID).
Documentation is added for cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-10-25 03:30:16 +08:00
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static int smp_spin_table_cpu_boot(unsigned int cpu)
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{
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unsigned long timeout;
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/*
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* Set synchronisation state between this boot processor
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* and the secondary one
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*/
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raw_spin_lock(&boot_lock);
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/*
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* Update the pen release flag.
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*/
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write_pen_release(cpu_logical_map(cpu));
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/*
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* Send an event, causing the secondaries to read pen_release.
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*/
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sev();
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timeout = jiffies + (1 * HZ);
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while (time_before(jiffies, timeout)) {
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if (secondary_holding_pen_release == INVALID_HWID)
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break;
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udelay(10);
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}
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/*
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* Now the secondary core is starting up let it run its
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* calibrations, then wait for it to finish
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*/
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raw_spin_unlock(&boot_lock);
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return secondary_holding_pen_release != INVALID_HWID ? -ENOSYS : 0;
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}
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2014-03-05 13:35:45 +08:00
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static void smp_spin_table_cpu_postboot(void)
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arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for
some systems where we can't bring CPUs online individually and must hold
multiple CPUs in a safe area until the kernel is able to handle them.
The current SMP infrastructure for arm64 is closely coupled to this
holding pen, and alternative boot methods must launch CPUs into the pen,
where they sit before they are launched into the kernel proper.
With PSCI (and possibly other future boot methods), we can bring CPUs
online individually, and need not perform the secondary_holding_pen
dance. Instead, this patch factors the holding pen management code out
to the spin-table boot method code, as it is the only boot method
requiring the pen.
A new entry point for secondaries, secondary_entry is added for other
boot methods to use, which bypasses the holding pen and its associated
overhead when bringing CPUs online. The smp.pen.text section is also
removed, as the pen can live in head.text without problem.
The cpu_operations structure is extended with two new functions,
cpu_boot and cpu_postboot, for bringing a cpu into the kernel and
performing any post-boot cleanup required by a bootmethod (e.g.
resetting the secondary_holding_pen_release to INVALID_HWID).
Documentation is added for cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-10-25 03:30:16 +08:00
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{
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/*
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* Let the primary processor know we're out of the pen.
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*/
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write_pen_release(INVALID_HWID);
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/*
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* Synchronise with the boot thread.
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*/
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raw_spin_lock(&boot_lock);
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raw_spin_unlock(&boot_lock);
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}
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2013-10-25 03:30:15 +08:00
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const struct cpu_operations smp_spin_table_ops = {
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2013-01-02 23:24:22 +08:00
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.name = "spin-table",
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2013-10-25 03:30:15 +08:00
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.cpu_init = smp_spin_table_cpu_init,
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.cpu_prepare = smp_spin_table_cpu_prepare,
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arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for
some systems where we can't bring CPUs online individually and must hold
multiple CPUs in a safe area until the kernel is able to handle them.
The current SMP infrastructure for arm64 is closely coupled to this
holding pen, and alternative boot methods must launch CPUs into the pen,
where they sit before they are launched into the kernel proper.
With PSCI (and possibly other future boot methods), we can bring CPUs
online individually, and need not perform the secondary_holding_pen
dance. Instead, this patch factors the holding pen management code out
to the spin-table boot method code, as it is the only boot method
requiring the pen.
A new entry point for secondaries, secondary_entry is added for other
boot methods to use, which bypasses the holding pen and its associated
overhead when bringing CPUs online. The smp.pen.text section is also
removed, as the pen can live in head.text without problem.
The cpu_operations structure is extended with two new functions,
cpu_boot and cpu_postboot, for bringing a cpu into the kernel and
performing any post-boot cleanup required by a bootmethod (e.g.
resetting the secondary_holding_pen_release to INVALID_HWID).
Documentation is added for cpu_operations.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-10-25 03:30:16 +08:00
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.cpu_boot = smp_spin_table_cpu_boot,
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.cpu_postboot = smp_spin_table_cpu_postboot,
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2013-01-02 23:24:22 +08:00
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};
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