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-rw-r--r--arch/tile/kernel/smp.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c
new file mode 100644
index 0000000..782c1bf
--- /dev/null
+++ b/arch/tile/kernel/smp.c
@@ -0,0 +1,202 @@
+/*
+ * Copyright 2010 Tilera Corporation. 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
+ * as published by the Free Software Foundation, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ *
+ * TILE SMP support routines.
+ */
+
+#include <linux/smp.h>
+#include <linux/irq.h>
+#include <asm/cacheflush.h>
+
+HV_Topology smp_topology __write_once;
+
+
+/*
+ * Top-level send_IPI*() functions to send messages to other cpus.
+ */
+
+/* Set by smp_send_stop() to avoid recursive panics. */
+static int stopping_cpus;
+
+void send_IPI_single(int cpu, int tag)
+{
+ HV_Recipient recip = {
+ .y = cpu / smp_width,
+ .x = cpu % smp_width,
+ .state = HV_TO_BE_SENT
+ };
+ int rc = hv_send_message(&recip, 1, (HV_VirtAddr)&tag, sizeof(tag));
+ BUG_ON(rc <= 0);
+}
+
+void send_IPI_many(const struct cpumask *mask, int tag)
+{
+ HV_Recipient recip[NR_CPUS];
+ int cpu, sent;
+ int nrecip = 0;
+ int my_cpu = smp_processor_id();
+ for_each_cpu(cpu, mask) {
+ HV_Recipient *r;
+ BUG_ON(cpu == my_cpu);
+ r = &recip[nrecip++];
+ r->y = cpu / smp_width;
+ r->x = cpu % smp_width;
+ r->state = HV_TO_BE_SENT;
+ }
+ sent = 0;
+ while (sent < nrecip) {
+ int rc = hv_send_message(recip, nrecip,
+ (HV_VirtAddr)&tag, sizeof(tag));
+ if (rc <= 0) {
+ if (!stopping_cpus) /* avoid recursive panic */
+ panic("hv_send_message returned %d", rc);
+ break;
+ }
+ sent += rc;
+ }
+}
+
+void send_IPI_allbutself(int tag)
+{
+ struct cpumask mask;
+ cpumask_copy(&mask, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), &mask);
+ send_IPI_many(&mask, tag);
+}
+
+
+/*
+ * Provide smp_call_function_mask, but also run function locally
+ * if specified in the mask.
+ */
+void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *),
+ void *info, bool wait)
+{
+ int cpu = get_cpu();
+ smp_call_function_many(mask, func, info, wait);
+ if (cpumask_test_cpu(cpu, mask)) {
+ local_irq_disable();
+ func(info);
+ local_irq_enable();
+ }
+ put_cpu();
+}
+
+
+/*
+ * Functions related to starting/stopping cpus.
+ */
+
+/* Handler to start the current cpu. */
+static void smp_start_cpu_interrupt(void)
+{
+ extern unsigned long start_cpu_function_addr;
+ get_irq_regs()->pc = start_cpu_function_addr;
+}
+
+/* Handler to stop the current cpu. */
+static void smp_stop_cpu_interrupt(void)
+{
+ set_cpu_online(smp_processor_id(), 0);
+ raw_local_irq_disable_all();
+ for (;;)
+ asm("nap");
+}
+
+/* This function calls the 'stop' function on all other CPUs in the system. */
+void smp_send_stop(void)
+{
+ stopping_cpus = 1;
+ send_IPI_allbutself(MSG_TAG_STOP_CPU);
+}
+
+
+/*
+ * Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages.
+ */
+void evaluate_message(int tag)
+{
+ switch (tag) {
+ case MSG_TAG_START_CPU: /* Start up a cpu */
+ smp_start_cpu_interrupt();
+ break;
+
+ case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */
+ smp_stop_cpu_interrupt();
+ break;
+
+ case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */
+ generic_smp_call_function_interrupt();
+ break;
+
+ case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */
+ generic_smp_call_function_single_interrupt();
+ break;
+
+ default:
+ panic("Unknown IPI message tag %d", tag);
+ break;
+ }
+}
+
+
+/*
+ * flush_icache_range() code uses smp_call_function().
+ */
+
+struct ipi_flush {
+ unsigned long start;
+ unsigned long end;
+};
+
+static void ipi_flush_icache_range(void *info)
+{
+ struct ipi_flush *flush = (struct ipi_flush *) info;
+ __flush_icache_range(flush->start, flush->end);
+}
+
+void flush_icache_range(unsigned long start, unsigned long end)
+{
+ struct ipi_flush flush = { start, end };
+ preempt_disable();
+ on_each_cpu(ipi_flush_icache_range, &flush, 1);
+ preempt_enable();
+}
+
+
+/*
+ * The smp_send_reschedule() path does not use the hv_message_intr()
+ * path but instead the faster tile_dev_intr() path for interrupts.
+ */
+
+irqreturn_t handle_reschedule_ipi(int irq, void *token)
+{
+ /*
+ * Nothing to do here; when we return from interrupt, the
+ * rescheduling will occur there. But do bump the interrupt
+ * profiler count in the meantime.
+ */
+ __get_cpu_var(irq_stat).irq_resched_count++;
+
+ return IRQ_HANDLED;
+}
+
+void smp_send_reschedule(int cpu)
+{
+ HV_Coord coord;
+
+ WARN_ON(cpu_is_offline(cpu));
+ coord.y = cpu / smp_width;
+ coord.x = cpu % smp_width;
+ hv_trigger_ipi(coord, IRQ_RESCHEDULE);
+}
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