MIPS: Yosemite, Emma: Fix off-by-two in arcs_cmdline buffer size check
[linux-2.6/linux-mips.git] / drivers / tty / hvc / hvc_xen.c
blob52fdf60bdbe2db44a7457a1392de002d3f79d79d
1 /*
2 * xen console driver interface to hvc_console.c
4 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/console.h>
22 #include <linux/delay.h>
23 #include <linux/err.h>
24 #include <linux/init.h>
25 #include <linux/types.h>
27 #include <asm/xen/hypervisor.h>
29 #include <xen/xen.h>
30 #include <xen/page.h>
31 #include <xen/events.h>
32 #include <xen/interface/io/console.h>
33 #include <xen/hvc-console.h>
35 #include "hvc_console.h"
37 #define HVC_COOKIE 0x58656e /* "Xen" in hex */
39 static struct hvc_struct *hvc;
40 static int xencons_irq;
42 /* ------------------------------------------------------------------ */
44 static unsigned long console_pfn = ~0ul;
46 static inline struct xencons_interface *xencons_interface(void)
48 if (console_pfn == ~0ul)
49 return mfn_to_virt(xen_start_info->console.domU.mfn);
50 else
51 return __va(console_pfn << PAGE_SHIFT);
54 static inline void notify_daemon(void)
56 /* Use evtchn: this is called early, before irq is set up. */
57 notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
60 static int __write_console(const char *data, int len)
62 struct xencons_interface *intf = xencons_interface();
63 XENCONS_RING_IDX cons, prod;
64 int sent = 0;
66 cons = intf->out_cons;
67 prod = intf->out_prod;
68 mb(); /* update queue values before going on */
69 BUG_ON((prod - cons) > sizeof(intf->out));
71 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
72 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
74 wmb(); /* write ring before updating pointer */
75 intf->out_prod = prod;
77 if (sent)
78 notify_daemon();
79 return sent;
82 static int domU_write_console(uint32_t vtermno, const char *data, int len)
84 int ret = len;
87 * Make sure the whole buffer is emitted, polling if
88 * necessary. We don't ever want to rely on the hvc daemon
89 * because the most interesting console output is when the
90 * kernel is crippled.
92 while (len) {
93 int sent = __write_console(data, len);
95 data += sent;
96 len -= sent;
98 if (unlikely(len))
99 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
102 return ret;
105 static int domU_read_console(uint32_t vtermno, char *buf, int len)
107 struct xencons_interface *intf = xencons_interface();
108 XENCONS_RING_IDX cons, prod;
109 int recv = 0;
111 cons = intf->in_cons;
112 prod = intf->in_prod;
113 mb(); /* get pointers before reading ring */
114 BUG_ON((prod - cons) > sizeof(intf->in));
116 while (cons != prod && recv < len)
117 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
119 mb(); /* read ring before consuming */
120 intf->in_cons = cons;
122 notify_daemon();
123 return recv;
126 static struct hv_ops domU_hvc_ops = {
127 .get_chars = domU_read_console,
128 .put_chars = domU_write_console,
129 .notifier_add = notifier_add_irq,
130 .notifier_del = notifier_del_irq,
131 .notifier_hangup = notifier_hangup_irq,
134 static int dom0_read_console(uint32_t vtermno, char *buf, int len)
136 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
140 * Either for a dom0 to write to the system console, or a domU with a
141 * debug version of Xen
143 static int dom0_write_console(uint32_t vtermno, const char *str, int len)
145 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
146 if (rc < 0)
147 return 0;
149 return len;
152 static struct hv_ops dom0_hvc_ops = {
153 .get_chars = dom0_read_console,
154 .put_chars = dom0_write_console,
155 .notifier_add = notifier_add_irq,
156 .notifier_del = notifier_del_irq,
157 .notifier_hangup = notifier_hangup_irq,
160 static int __init xen_hvc_init(void)
162 struct hvc_struct *hp;
163 struct hv_ops *ops;
165 if (!xen_pv_domain())
166 return -ENODEV;
168 if (xen_initial_domain()) {
169 ops = &dom0_hvc_ops;
170 xencons_irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
171 } else {
172 if (!xen_start_info->console.domU.evtchn)
173 return -ENODEV;
175 ops = &domU_hvc_ops;
176 xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
178 if (xencons_irq < 0)
179 xencons_irq = 0; /* NO_IRQ */
180 else
181 irq_set_noprobe(xencons_irq);
183 hp = hvc_alloc(HVC_COOKIE, xencons_irq, ops, 256);
184 if (IS_ERR(hp))
185 return PTR_ERR(hp);
187 hvc = hp;
189 console_pfn = mfn_to_pfn(xen_start_info->console.domU.mfn);
191 return 0;
194 void xen_console_resume(void)
196 if (xencons_irq)
197 rebind_evtchn_irq(xen_start_info->console.domU.evtchn, xencons_irq);
200 static void __exit xen_hvc_fini(void)
202 if (hvc)
203 hvc_remove(hvc);
206 static int xen_cons_init(void)
208 struct hv_ops *ops;
210 if (!xen_pv_domain())
211 return 0;
213 if (xen_initial_domain())
214 ops = &dom0_hvc_ops;
215 else
216 ops = &domU_hvc_ops;
218 hvc_instantiate(HVC_COOKIE, 0, ops);
219 return 0;
222 module_init(xen_hvc_init);
223 module_exit(xen_hvc_fini);
224 console_initcall(xen_cons_init);
226 #ifdef CONFIG_EARLY_PRINTK
227 static void xenboot_write_console(struct console *console, const char *string,
228 unsigned len)
230 unsigned int linelen, off = 0;
231 const char *pos;
233 dom0_write_console(0, string, len);
235 if (xen_initial_domain())
236 return;
238 domU_write_console(0, "(early) ", 8);
239 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
240 linelen = pos-string+off;
241 if (off + linelen > len)
242 break;
243 domU_write_console(0, string+off, linelen);
244 domU_write_console(0, "\r\n", 2);
245 off += linelen + 1;
247 if (off < len)
248 domU_write_console(0, string+off, len-off);
251 struct console xenboot_console = {
252 .name = "xenboot",
253 .write = xenboot_write_console,
254 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
256 #endif /* CONFIG_EARLY_PRINTK */
258 void xen_raw_console_write(const char *str)
260 dom0_write_console(0, str, strlen(str));
263 void xen_raw_printk(const char *fmt, ...)
265 static char buf[512];
266 va_list ap;
268 va_start(ap, fmt);
269 vsnprintf(buf, sizeof(buf), fmt, ap);
270 va_end(ap);
272 xen_raw_console_write(buf);