osfmk/console/i386/serial_console.c

   1 /*
   2  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <i386/mp.h>
  30 #include <i386/cpu_data.h>
  31 #include <i386/machine_cpu.h>
  32 #include <i386/machine_routines.h>
  33 #include <i386/misc_protos.h>
  34 #include <i386/serial_io.h>
  35 #include <vm/vm_kern.h>
  36 #include <console/video_console.h>
  37 #include <console/serial_protos.h>
  38 #include <kern/kalloc.h>
  39
  40 static struct {
  41         char    *buffer;
  42         int     len;
  43         int     used;
  44         char    *write_ptr;
  45         char    *read_ptr;
  46         decl_simple_lock_data(,read_lock);
  47         decl_simple_lock_data(,write_lock);
  48 } console_ring;
  49
  50 hw_lock_data_t cnputc_lock;
  51 static volatile long console_output = 0;
  52
  53 typedef struct console_buf {
  54         char    *buf_base;
  55         char    *buf_end;
  56         char    *buf_ptr;
  57 #define CPU_BUFFER_LEN  (256 - 3*(sizeof(char*)))
  58         char    buf[CPU_BUFFER_LEN];
  59 } console_buf_t;
  60
  61 static void _serial_putc(int, int, int);
  62
  63 struct console_ops cons_ops[] = {
  64         {
  65                 .putc = _serial_putc,
  66                 .getc = _serial_getc,
  67         },
  68         {
  69                 .putc = vcputc,
  70                 .getc = vcgetc,
  71         },
  72 };
  73
  74 uint32_t nconsops = (sizeof cons_ops / sizeof cons_ops[0]);
  75
  76 uint32_t cons_ops_index = VC_CONS_OPS;
  77
  78 /* This macro polls for pending TLB flushes while spinning on a lock
  79  */
  80 #define SIMPLE_LOCK_NO_INTRS(l)                         \
  81 MACRO_BEGIN                                             \
  82         boolean_t istate = ml_get_interrupts_enabled(); \
  83         while (!simple_lock_try((l)))                   \
  84         {                                               \
  85                 if (!istate)                            \
  86                         handle_pending_TLB_flushes();   \
  87                 cpu_pause();                            \
  88         }                                               \
  89 MACRO_END
  90
  91 void
  92 console_init(void)
  93 {
  94         int     ret;
  95
  96         console_ring.len = PAGE_SIZE;
  97         ret = kmem_alloc(kernel_map, (vm_offset_t *) &console_ring.buffer,
  98                          console_ring.len);
  99         if (ret != KERN_SUCCESS)
 100                 panic("console_ring_init() "
 101                       "failed to allocate ring buffer, error %d\n", ret);
 102         console_ring.used = 0;
 103         console_ring.read_ptr = console_ring.buffer;
 104         console_ring.write_ptr = console_ring.buffer;
 105         simple_lock_init(&console_ring.read_lock, 0);
 106         simple_lock_init(&console_ring.write_lock, 0);
 107         hw_lock_init(&cnputc_lock);
 108 }
 109
 110 void *
 111 console_cpu_alloc(__unused boolean_t boot_processor)
 112 {
 113         int             ret;
 114         console_buf_t   *cbp;
 115
 116         ret = kmem_alloc(kernel_map, (vm_offset_t *) &cbp,
 117                                 sizeof(console_buf_t));
 118         if (ret != KERN_SUCCESS) {
 119                 printf("console_cpu_alloc() "
 120                       "failed to allocate cpu buffer, error=%d\n", ret);
 121                 return NULL;
 122         }
 123
 124         cbp->buf_base = (char *) &cbp->buf;
 125         cbp->buf_ptr = cbp->buf_base;
 126         cbp->buf_end = cbp->buf_base + CPU_BUFFER_LEN;
 127
 128         return (void *) cbp;
 129 }
 130
 131 void
 132 console_cpu_free(void *buf)
 133 {
 134         if (buf != NULL)
 135                 kfree((void *) buf, sizeof(console_buf_t));
 136 }
 137
 138 /* So we can re-write the serial device functions at boot-time */
 139 void
 140 console_set_serial_ops( struct console_ops *newops )
 141 {
 142         cons_ops[SERIAL_CONS_OPS] = *newops;
 143 }
 144
 145 static inline int
 146 console_ring_space(void)
 147 {
 148         return console_ring.len - console_ring.used;
 149 }
 150
 151 static boolean_t
 152 console_ring_put(char ch)
 153 {
 154         if (console_ring.used < console_ring.len) {
 155                 console_ring.used++;;
 156                 *console_ring.write_ptr++ = ch;
 157                 if (console_ring.write_ptr - console_ring.buffer
 158                     == console_ring.len)
 159                         console_ring.write_ptr = console_ring.buffer;
 160                 return TRUE;
 161         } else {
 162                 return FALSE;
 163         }
 164 }
 165
 166 static int
 167 console_ring_get(void)
 168 {
 169         char    ch = 0;
 170
 171         if (console_ring.used > 0) {
 172                 console_ring.used--;
 173                 ch = *console_ring.read_ptr++;
 174                 if (console_ring.read_ptr - console_ring.buffer
 175                     == console_ring.len)
 176                         console_ring.read_ptr = console_ring.buffer;
 177         }
 178         return (int) ch;
 179 }
 180
 181 static inline void
 182 cpu_buffer_put(console_buf_t *cbp, char ch)
 183 {
 184         if (ch != '\0' && cbp->buf_ptr < cbp->buf_end)
 185                 *(cbp->buf_ptr++) = ch;
 186 }
 187
 188 static inline void
 189 _cnputc(char c)
 190 {
 191         /* The console device output routines are assumed to be
 192          * non-reentrant.
 193          */
 194         mp_disable_preemption();
 195         if (!hw_lock_to(&cnputc_lock, LockTimeOutTSC)) {
 196         /* If we timed out on the lock, and we're in the debugger,
 197          * break the lock.
 198          */
 199                 if (debug_mode) {
 200                         /* Since hw_lock_to takes a pre-emption count...*/
 201                         mp_enable_preemption();
 202                         hw_lock_init(&cnputc_lock);
 203                         hw_lock_lock(&cnputc_lock);
 204                 }
 205                 else
 206                         panic("Lock acquire timeout in _cnputc()");
 207         }
 208         cons_ops[cons_ops_index].putc(0, 0, c);
 209         if (c == '\n')
 210             cons_ops[cons_ops_index].putc(0, 0, '\r');
 211         hw_lock_unlock(&cnputc_lock);
 212         mp_enable_preemption();
 213 }
 214
 215 void cnputc_unbuffered(char c) {
 216         _cnputc(c);
 217 }
 218
 219 void
 220 cnputcusr(char c)
 221 {
 222         /* Spin (with pre-emption enabled) waiting for console_ring_try_empty()
 223          * to complete output. There is a small window here where we could
 224          * end up with a stale value of console_output, but it's unlikely,
 225          * and _cnputc(), which outputs to the console device, is internally
 226          * synchronized. There's something of a conflict between the
 227          * character-at-a-time (with pre-emption enabled) unbuffered
 228          * output model here, and the buffered output from cnputc(),
 229          * whose consumers include printf() ( which outputs a sequence
 230          * with pre-emption disabled, and should be safe to call with
 231          * interrupts off); we don't want to disable pre-emption indefinitely
 232          * here, and spinlocks and mutexes are inappropriate.
 233          */
 234         while (console_output != 0);
 235
 236         _cnputc(c);
 237 }
 238
 239 static void
 240 console_ring_try_empty(void)
 241 {
 242         boolean_t state = ml_get_interrupts_enabled();
 243         /*
 244          * Try to get the read lock on the ring buffer to empty it.
 245          * If this fails someone else is already emptying...
 246          */
 247         if (!simple_lock_try(&console_ring.read_lock))
 248                 return;
 249         /* Indicate that we're in the process of writing a block of data
 250          * to the console.
 251          */
 252         atomic_incl(&console_output, 1);
 253         for (;;) {
 254                 char    ch;
 255                 if (!state)
 256                         handle_pending_TLB_flushes();
 257                 SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
 258                 ch = console_ring_get();
 259                 simple_unlock(&console_ring.write_lock);
 260                 if (ch == 0)
 261                         break;
 262                 _cnputc(ch);
 263         }
 264         atomic_decl(&console_output, 1);
 265         simple_unlock(&console_ring.read_lock);
 266 }
 267
 268 void
 269 cnputc(char c)
 270 {
 271         console_buf_t   *cbp;
 272 #if MACH_KDB
 273         /* Bypass locking/buffering if in debugger */
 274         if (kdb_cpu == cpu_number()) {
 275                 _cnputc(c);
 276                 return;
 277         }
 278 #endif /* MACH_KDB */
 279         mp_disable_preemption();
 280         cbp = (console_buf_t *) current_cpu_datap()->cpu_console_buf;
 281         if (cbp == NULL) {
 282                 mp_enable_preemption();
 283                 /* Put directly if console ring is not initialized */
 284                 _cnputc(c);
 285                 return;
 286         }
 287
 288         /* add to stack buf */
 289         if (c != '\n') {
 290                 /* XXX - cpu_buffer_put() can fail silently if the buffer
 291                  * is exhausted, as can happen if there's a long sequence
 292                  * of data with no newlines. We should, instead, attempt
 293                  * a flush.
 294                  */
 295                 cpu_buffer_put(cbp, c);
 296         } else {
 297                 boolean_t       state;
 298                 char            *cp;
 299
 300                 /* Here at end of printf -- time to try to output */
 301
 302                 /* copy this buffer into the shared ring buffer */
 303                 state = ml_set_interrupts_enabled(FALSE);
 304                 SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
 305
 306                 /*
 307                  * Is there enough space in the shared ring buffer?
 308                  * Try to empty if not.
 309                  * Note, we want the entire local buffer to fit to
 310                  * avoid another cpu interjecting.
 311                  */
 312                 while (cbp->buf_ptr-cbp->buf_base + 1 > console_ring_space()) {
 313                         simple_unlock(&console_ring.write_lock);
 314                         ml_set_interrupts_enabled(state);
 315                         console_ring_try_empty();
 316                         state = ml_set_interrupts_enabled(FALSE);
 317                         SIMPLE_LOCK_NO_INTRS(&console_ring.write_lock);
 318                 }
 319                 for (cp = cbp->buf_base; cp < cbp->buf_ptr; cp++)
 320                         console_ring_put(*cp);
 321                 console_ring_put('\n');
 322                 cbp->buf_ptr = cbp->buf_base;
 323                 simple_unlock(&console_ring.write_lock);
 324                 ml_set_interrupts_enabled(state);
 325         }
 326         console_ring_try_empty();
 327         mp_enable_preemption();
 328 }
 329
 330 int _serial_getc(__unused int a, __unused int b, boolean_t wait, __unused boolean_t raw)
 331 {
 332     int c;
 333     do {
 334         c = serial_getc();
 335     } while (wait && c < 0);
 336
 337     return c;
 338 }
 339
 340 static void _serial_putc(__unused int a, __unused int b, int c)
 341 {
 342     serial_putc(c);
 343 }
 344
 345
 346 int
 347 cngetc(void)
 348 {
 349         return cons_ops[cons_ops_index].getc(0, 0,
 350                                              TRUE, FALSE);
 351 }
 352
 353 int
 354 cnmaygetc(void)
 355 {
 356         return cons_ops[cons_ops_index].getc(0, 0,
 357                                              FALSE, FALSE);
 358 }
 359
 360 int
 361 vcgetc(__unused int l,
 362        __unused int u,
 363        __unused boolean_t wait,
 364        __unused boolean_t raw)
 365 {
 366         char c;
 367
 368         if( 0 == (*PE_poll_input)( 0, &c))
 369                 return( c);
 370         else
 371                 return( 0);
 372 }