1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 *   This program is free software; you can redistribute it and/or
5 *   modify it under the terms of the GNU General Public License
6 *   as published by the Free Software Foundation, version 2.
7 *
8 *   This program is distributed in the hope that it will be useful, but
9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 *   NON INFRINGEMENT.  See the GNU General Public License for
12 *   more details.
13 */
14
15#include <linux/percpu.h>
16#include <linux/smp.h>
17#include <linux/hardirq.h>
18#include <linux/ptrace.h>
19#include <asm/hv_driver.h>
20#include <asm/irq_regs.h>
21#include <asm/traps.h>
22#include <hv/hypervisor.h>
23#include <arch/interrupts.h>
24
25/* All messages are stored here */
26static DEFINE_PER_CPU(HV_MsgState, msg_state);
27
28void __cpuinit init_messaging(void)
29{
30	/* Allocate storage for messages in kernel space */
31	HV_MsgState *state = &__get_cpu_var(msg_state);
32	int rc = hv_register_message_state(state);
33	if (rc != HV_OK)
34		panic("hv_register_message_state: error %d", rc);
35
36	/* Make sure downcall interrupts will be enabled. */
37	arch_local_irq_unmask(INT_INTCTRL_K);
38}
39
40void hv_message_intr(struct pt_regs *regs, int intnum)
41{
42	/*
43	 * We enter with interrupts disabled and leave them disabled,
44	 * to match expectations of called functions (e.g.
45	 * do_ccupdate_local() in mm/slab.c).  This is also consistent
46	 * with normal call entry for device interrupts.
47	 */
48
49	int message[HV_MAX_MESSAGE_SIZE/sizeof(int)];
50	HV_RcvMsgInfo rmi;
51	int nmsgs = 0;
52
53	/* Track time spent here in an interrupt context */
54	struct pt_regs *old_regs = set_irq_regs(regs);
55	irq_enter();
56
57#ifdef CONFIG_DEBUG_STACKOVERFLOW
58	/* Debugging check for stack overflow: less than 1/8th stack free? */
59	{
60		long sp = stack_pointer - (long) current_thread_info();
61		if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
62			pr_emerg("hv_message_intr: "
63			       "stack overflow: %ld\n",
64			       sp - sizeof(struct thread_info));
65			dump_stack();
66		}
67	}
68#endif
69
70	while (1) {
71		rmi = hv_receive_message(__get_cpu_var(msg_state),
72					 (HV_VirtAddr) message,
73					 sizeof(message));
74		if (rmi.msglen == 0)
75			break;
76
77		if (rmi.msglen < 0)
78			panic("hv_receive_message failed: %d", rmi.msglen);
79
80		++nmsgs;
81
82		if (rmi.source == HV_MSG_TILE) {
83			int tag;
84
85			/* we just send tags for now */
86			BUG_ON(rmi.msglen != sizeof(int));
87
88			tag = message[0];
89#ifdef CONFIG_SMP
90			evaluate_message(message[0]);
91#else
92			panic("Received IPI message %d in UP mode", tag);
93#endif
94		} else if (rmi.source == HV_MSG_INTR) {
95			HV_IntrMsg *him = (HV_IntrMsg *)message;
96			struct hv_driver_cb *cb =
97				(struct hv_driver_cb *)him->intarg;
98			cb->callback(cb, him->intdata);
99			__get_cpu_var(irq_stat).irq_hv_msg_count++;
100		}
101	}
102
103	/*
104	 * We shouldn't have gotten a message downcall with no
105	 * messages available.
106	 */
107	if (nmsgs == 0)
108		panic("Message downcall invoked with no messages!");
109
110	/*
111	 * Track time spent against the current process again and
112	 * process any softirqs if they are waiting.
113	 */
114	irq_exit();
115	set_irq_regs(old_regs);
116}
117