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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/tile/kernel/messaging.c
Initial import
Diffstat (limited to 'arch/tile/kernel/messaging.c')
-rw-r--r--arch/tile/kernel/messaging.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/arch/tile/kernel/messaging.c b/arch/tile/kernel/messaging.c
new file mode 100644
index 000000000..7475af3aa
--- /dev/null
+++ b/arch/tile/kernel/messaging.c
@@ -0,0 +1,115 @@
+/*
+ * 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.
+ */
+
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/hardirq.h>
+#include <linux/ptrace.h>
+#include <asm/hv_driver.h>
+#include <asm/irq_regs.h>
+#include <asm/traps.h>
+#include <hv/hypervisor.h>
+#include <arch/interrupts.h>
+
+/* All messages are stored here */
+static DEFINE_PER_CPU(HV_MsgState, msg_state);
+
+void init_messaging(void)
+{
+ /* Allocate storage for messages in kernel space */
+ HV_MsgState *state = this_cpu_ptr(&msg_state);
+ int rc = hv_register_message_state(state);
+ if (rc != HV_OK)
+ panic("hv_register_message_state: error %d", rc);
+
+ /* Make sure downcall interrupts will be enabled. */
+ arch_local_irq_unmask(INT_INTCTRL_K);
+}
+
+void hv_message_intr(struct pt_regs *regs, int intnum)
+{
+ /*
+ * We enter with interrupts disabled and leave them disabled,
+ * to match expectations of called functions (e.g.
+ * do_ccupdate_local() in mm/slab.c). This is also consistent
+ * with normal call entry for device interrupts.
+ */
+
+ int message[HV_MAX_MESSAGE_SIZE/sizeof(int)];
+ HV_RcvMsgInfo rmi;
+ int nmsgs = 0;
+
+ /* Track time spent here in an interrupt context */
+ struct pt_regs *old_regs = set_irq_regs(regs);
+ irq_enter();
+
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+ /* Debugging check for stack overflow: less than 1/8th stack free? */
+ {
+ long sp = stack_pointer - (long) current_thread_info();
+ if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
+ pr_emerg("%s: stack overflow: %ld\n",
+ __func__, sp - sizeof(struct thread_info));
+ dump_stack();
+ }
+ }
+#endif
+
+ while (1) {
+ HV_MsgState *state = this_cpu_ptr(&msg_state);
+ rmi = hv_receive_message(*state, (HV_VirtAddr) message,
+ sizeof(message));
+ if (rmi.msglen == 0)
+ break;
+
+ if (rmi.msglen < 0)
+ panic("hv_receive_message failed: %d", rmi.msglen);
+
+ ++nmsgs;
+
+ if (rmi.source == HV_MSG_TILE) {
+ int tag;
+
+ /* we just send tags for now */
+ BUG_ON(rmi.msglen != sizeof(int));
+
+ tag = message[0];
+#ifdef CONFIG_SMP
+ evaluate_message(message[0]);
+#else
+ panic("Received IPI message %d in UP mode", tag);
+#endif
+ } else if (rmi.source == HV_MSG_INTR) {
+ HV_IntrMsg *him = (HV_IntrMsg *)message;
+ struct hv_driver_cb *cb =
+ (struct hv_driver_cb *)him->intarg;
+ cb->callback(cb, him->intdata);
+ __this_cpu_inc(irq_stat.irq_hv_msg_count);
+ }
+ }
+
+ /*
+ * We shouldn't have gotten a message downcall with no
+ * messages available.
+ */
+ if (nmsgs == 0)
+ panic("Message downcall invoked with no messages!");
+
+ /*
+ * Track time spent against the current process again and
+ * process any softirqs if they are waiting.
+ */
+ irq_exit();
+ set_irq_regs(old_regs);
+}