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 init_messaging(void)
29 {
30 /* Allocate storage for messages in kernel space */
31 HV_MsgState *state = this_cpu_ptr(&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("%s: stack overflow: %ld\n",
63 __func__, sp - sizeof(struct thread_info));
64 dump_stack();
65 }
66 }
67 #endif
68
69 while (1) {
70 HV_MsgState *state = this_cpu_ptr(&msg_state);
71 rmi = hv_receive_message(*state, (HV_VirtAddr) message,
72 sizeof(message));
73 if (rmi.msglen == 0)
74 break;
75
76 if (rmi.msglen < 0)
77 panic("hv_receive_message failed: %d", rmi.msglen);
78
79 ++nmsgs;
80
81 if (rmi.source == HV_MSG_TILE) {
82 int tag;
83
84 /* we just send tags for now */
85 BUG_ON(rmi.msglen != sizeof(int));
86
87 tag = message[0];
88 #ifdef CONFIG_SMP
89 evaluate_message(message[0]);
90 #else
91 panic("Received IPI message %d in UP mode", tag);
92 #endif
93 } else if (rmi.source == HV_MSG_INTR) {
94 HV_IntrMsg *him = (HV_IntrMsg *)message;
95 struct hv_driver_cb *cb =
96 (struct hv_driver_cb *)him->intarg;
97 cb->callback(cb, him->intdata);
98 __this_cpu_inc(irq_stat.irq_hv_msg_count);
99 }
100 }
101
102 /*
103 * We shouldn't have gotten a message downcall with no
104 * messages available.
105 */
106 if (nmsgs == 0)
107 panic("Message downcall invoked with no messages!");
108
109 /*
110 * Track time spent against the current process again and
111 * process any softirqs if they are waiting.
112 */
113 irq_exit();
114 set_irq_regs(old_regs);
115 }
116