File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
new file mode 100644
index 0000000..ff759f2
--- /dev/null
+++ b/arch/hexagon/kernel/smp.c
@@ -0,0 +1,266 @@
+/*
+ * SMP support for Hexagon
+ *
+ * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/cpu.h>
+
+#include <asm/time.h> /* timer_interrupt */
+#include <asm/hexagon_vm.h>
+
+#define BASE_IPI_IRQ 26
+
+/*
+ * cpu_possible_mask needs to be filled out prior to setup_per_cpu_areas
+ * (which is prior to any of our smp_prepare_cpu crap), in order to set
+ * up the... per_cpu areas.
+ */
+
+struct ipi_data {
+ unsigned long bits;
+};
+
+static DEFINE_PER_CPU(struct ipi_data, ipi_data);
+
+static inline void __handle_ipi(unsigned long *ops, struct ipi_data *ipi,
+ int cpu)
+{
+ unsigned long msg = 0;
+ do {
+ msg = find_next_bit(ops, BITS_PER_LONG, msg+1);
+
+ switch (msg) {
+
+ case IPI_TIMER:
+ ipi_timer();
+ break;
+
+ case IPI_CALL_FUNC:
+ generic_smp_call_function_interrupt();
+ break;
+
+ case IPI_CPU_STOP:
+ /*
+ * call vmstop()
+ */
+ __vmstop();
+ break;
+
+ case IPI_RESCHEDULE:
+ scheduler_ipi();
+ break;
+ }
+ } while (msg < BITS_PER_LONG);
+}
+
+/* Used for IPI call from other CPU's to unmask int */
+void smp_vm_unmask_irq(void *info)
+{
+ __vmintop_locen((long) info);
+}
+
+
+/*
+ * This is based on Alpha's IPI stuff.
+ * Supposed to take (int, void*) as args now.
+ * Specifically, first arg is irq, second is the irq_desc.
+ */
+
+irqreturn_t handle_ipi(int irq, void *desc)
+{
+ int cpu = smp_processor_id();
+ struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
+ unsigned long ops;
+
+ while ((ops = xchg(&ipi->bits, 0)) != 0)
+ __handle_ipi(&ops, ipi, cpu);
+ return IRQ_HANDLED;
+}
+
+void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
+{
+ unsigned long flags;
+ unsigned long cpu;
+ unsigned long retval;
+
+ local_irq_save(flags);
+
+ for_each_cpu(cpu, cpumask) {
+ struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
+
+ set_bit(msg, &ipi->bits);
+ /* Possible barrier here */
+ retval = __vmintop_post(BASE_IPI_IRQ+cpu);
+
+ if (retval != 0) {
+ printk(KERN_ERR "interrupt %ld not configured?\n",
+ BASE_IPI_IRQ+cpu);
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
+static struct irqaction ipi_intdesc = {
+ .handler = handle_ipi,
+ .flags = IRQF_TRIGGER_RISING,
+ .name = "ipi_handler"
+};
+
+void __init smp_prepare_boot_cpu(void)
+{
+}
+
+/*
+ * interrupts should already be disabled from the VM
+ * SP should already be correct; need to set THREADINFO_REG
+ * to point to current thread info
+ */
+
+void start_secondary(void)
+{
+ unsigned int cpu;
+ unsigned long thread_ptr;
+
+ /* Calculate thread_info pointer from stack pointer */
+ __asm__ __volatile__(
+ "%0 = SP;\n"
+ : "=r" (thread_ptr)
+ );
+
+ thread_ptr = thread_ptr & ~(THREAD_SIZE-1);
+
+ __asm__ __volatile__(
+ QUOTED_THREADINFO_REG " = %0;\n"
+ :
+ : "r" (thread_ptr)
+ );
+
+ /* Set the memory struct */
+ atomic_inc(&init_mm.mm_count);
+ current->active_mm = &init_mm;
+
+ cpu = smp_processor_id();
+
+ setup_irq(BASE_IPI_IRQ + cpu, &ipi_intdesc);
+
+ /* Register the clock_event dummy */
+ setup_percpu_clockdev();
+
+ printk(KERN_INFO "%s cpu %d\n", __func__, current_thread_info()->cpu);
+
+ notify_cpu_starting(cpu);
+
+ set_cpu_online(cpu, true);
+
+ local_irq_enable();
+
+ cpu_startup_entry(CPUHP_ONLINE);
+}
+
+
+/*
+ * called once for each present cpu
+ * apparently starts up the CPU and then
+ * maintains control until "cpu_online(cpu)" is set.
+ */
+
+int __cpu_up(unsigned int cpu, struct task_struct *idle)
+{
+ struct thread_info *thread = (struct thread_info *)idle->stack;
+ void *stack_start;
+
+ thread->cpu = cpu;
+
+ /* Boot to the head. */
+ stack_start = ((void *) thread) + THREAD_SIZE;
+ __vmstart(start_secondary, stack_start);
+
+ while (!cpu_online(cpu))
+ barrier();
+
+ return 0;
+}
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+ int i;
+
+ /*
+ * should eventually have some sort of machine
+ * descriptor that has this stuff
+ */
+
+ /* Right now, let's just fake it. */
+ for (i = 0; i < max_cpus; i++)
+ set_cpu_present(i, true);
+
+ /* Also need to register the interrupts for IPI */
+ if (max_cpus > 1)
+ setup_irq(BASE_IPI_IRQ, &ipi_intdesc);
+}
+
+void smp_send_reschedule(int cpu)
+{
+ send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
+}
+
+void smp_send_stop(void)
+{
+ struct cpumask targets;
+ cpumask_copy(&targets, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), &targets);
+ send_ipi(&targets, IPI_CPU_STOP);
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+ send_ipi(cpumask_of(cpu), IPI_CALL_FUNC);
+}
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+ send_ipi(mask, IPI_CALL_FUNC);
+}
+
+int setup_profiling_timer(unsigned int multiplier)
+{
+ return -EINVAL;
+}
+
+void smp_start_cpus(void)
+{
+ int i;
+
+ for (i = 0; i < NR_CPUS; i++)
+ set_cpu_possible(i, true);
+}