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 */
26 static DEFINE_PER_CPU(HV_MsgState, msg_state);
27
init_messaging(void)28 void __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
hv_message_intr(struct pt_regs * regs,int intnum)40 void 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