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-rw-r--r--arch/sh/kernel/kgdb_stub.c1052
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diff --git a/arch/sh/kernel/kgdb_stub.c b/arch/sh/kernel/kgdb_stub.c
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1/*
2 * May be copied or modified under the terms of the GNU General Public
3 * License. See linux/COPYING for more information.
4 *
5 * Contains extracts from code by Glenn Engel, Jim Kingdon,
6 * David Grothe <dave@gcom.com>, Tigran Aivazian <tigran@sco.com>,
7 * Amit S. Kale <akale@veritas.com>, William Gatliff <bgat@open-widgets.com>,
8 * Ben Lee, Steve Chamberlain and Benoit Miller <fulg@iname.com>.
9 *
10 * This version by Henry Bell <henry.bell@st.com>
11 * Minor modifications by Jeremy Siegel <jsiegel@mvista.com>
12 *
13 * Contains low-level support for remote debug using GDB.
14 *
15 * To enable debugger support, two things need to happen. A call to
16 * set_debug_traps() is necessary in order to allow any breakpoints
17 * or error conditions to be properly intercepted and reported to gdb.
18 * A breakpoint also needs to be generated to begin communication. This
19 * is most easily accomplished by a call to breakpoint() which does
20 * a trapa if the initialisation phase has been successfully completed.
21 *
22 * In this case, set_debug_traps() is not used to "take over" exceptions;
23 * other kernel code is modified instead to enter the kgdb functions here
24 * when appropriate (see entry.S for breakpoint traps and NMI interrupts,
25 * see traps.c for kernel error exceptions).
26 *
27 * The following gdb commands are supported:
28 *
29 * Command Function Return value
30 *
31 * g return the value of the CPU registers hex data or ENN
32 * G set the value of the CPU registers OK or ENN
33 *
34 * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN
35 * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN
36 * XAA..AA,LLLL: Same, but data is binary (not hex) OK or ENN
37 *
38 * c Resume at current address SNN ( signal NN)
39 * cAA..AA Continue at address AA..AA SNN
40 * CNN; Resume at current address with signal SNN
41 * CNN;AA..AA Resume at address AA..AA with signal SNN
42 *
43 * s Step one instruction SNN
44 * sAA..AA Step one instruction from AA..AA SNN
45 * SNN; Step one instruction with signal SNN
46 * SNNAA..AA Step one instruction from AA..AA w/NN SNN
47 *
48 * k kill (Detach GDB)
49 *
50 * d Toggle debug flag
51 * D Detach GDB
52 *
53 * Hct Set thread t for operations, OK or ENN
54 * c = 'c' (step, cont), c = 'g' (other
55 * operations)
56 *
57 * qC Query current thread ID QCpid
58 * qfThreadInfo Get list of current threads (first) m<id>
59 * qsThreadInfo " " " " " (subsequent)
60 * qOffsets Get section offsets Text=x;Data=y;Bss=z
61 *
62 * TXX Find if thread XX is alive OK or ENN
63 * ? What was the last sigval ? SNN (signal NN)
64 * O Output to GDB console
65 *
66 * Remote communication protocol.
67 *
68 * A debug packet whose contents are <data> is encapsulated for
69 * transmission in the form:
70 *
71 * $ <data> # CSUM1 CSUM2
72 *
73 * <data> must be ASCII alphanumeric and cannot include characters
74 * '$' or '#'. If <data> starts with two characters followed by
75 * ':', then the existing stubs interpret this as a sequence number.
76 *
77 * CSUM1 and CSUM2 are ascii hex representation of an 8-bit
78 * checksum of <data>, the most significant nibble is sent first.
79 * the hex digits 0-9,a-f are used.
80 *
81 * Receiver responds with:
82 *
83 * + - if CSUM is correct and ready for next packet
84 * - - if CSUM is incorrect
85 *
86 * Responses can be run-length encoded to save space. A '*' means that
87 * the next character is an ASCII encoding giving a repeat count which
88 * stands for that many repetitions of the character preceding the '*'.
89 * The encoding is n+29, yielding a printable character where n >=3
90 * (which is where RLE starts to win). Don't use an n > 126.
91 *
92 * So "0* " means the same as "0000".
93 */
94
95#include <linux/string.h>
96#include <linux/kernel.h>
97#include <linux/sched.h>
98#include <linux/smp.h>
99#include <linux/spinlock.h>
100#include <linux/delay.h>
101#include <linux/linkage.h>
102#include <linux/init.h>
103#include <linux/console.h>
104#include <linux/sysrq.h>
105#include <linux/module.h>
106#include <asm/system.h>
107#include <asm/cacheflush.h>
108#include <asm/current.h>
109#include <asm/signal.h>
110#include <asm/pgtable.h>
111#include <asm/ptrace.h>
112#include <asm/kgdb.h>
113#include <asm/io.h>
114
115/* Function pointers for linkage */
116kgdb_debug_hook_t *kgdb_debug_hook;
117kgdb_bus_error_hook_t *kgdb_bus_err_hook;
118
119int (*kgdb_getchar)(void);
120EXPORT_SYMBOL_GPL(kgdb_getchar);
121void (*kgdb_putchar)(int);
122EXPORT_SYMBOL_GPL(kgdb_putchar);
123
124static void put_debug_char(int c)
125{
126 if (!kgdb_putchar)
127 return;
128 (*kgdb_putchar)(c);
129}
130static int get_debug_char(void)
131{
132 if (!kgdb_getchar)
133 return -1;
134 return (*kgdb_getchar)();
135}
136
137/* Num chars in in/out bound buffers, register packets need NUMREGBYTES * 2 */
138#define BUFMAX 1024
139#define NUMREGBYTES (MAXREG*4)
140#define OUTBUFMAX (NUMREGBYTES*2+512)
141
142enum {
143 R0 = 0, R1, R2, R3, R4, R5, R6, R7,
144 R8, R9, R10, R11, R12, R13, R14, R15,
145 PC, PR, GBR, VBR, MACH, MACL, SR,
146 /* */
147 MAXREG
148};
149
150static unsigned int registers[MAXREG];
151struct kgdb_regs trap_registers;
152
153char kgdb_in_gdb_mode;
154char in_nmi; /* Set during NMI to prevent reentry */
155int kgdb_nofault; /* Boolean to ignore bus errs (i.e. in GDB) */
156
157/* Default values for SCI (can override via kernel args in setup.c) */
158#ifndef CONFIG_KGDB_DEFPORT
159#define CONFIG_KGDB_DEFPORT 1
160#endif
161
162#ifndef CONFIG_KGDB_DEFBAUD
163#define CONFIG_KGDB_DEFBAUD 115200
164#endif
165
166#if defined(CONFIG_KGDB_DEFPARITY_E)
167#define CONFIG_KGDB_DEFPARITY 'E'
168#elif defined(CONFIG_KGDB_DEFPARITY_O)
169#define CONFIG_KGDB_DEFPARITY 'O'
170#else /* CONFIG_KGDB_DEFPARITY_N */
171#define CONFIG_KGDB_DEFPARITY 'N'
172#endif
173
174#ifdef CONFIG_KGDB_DEFBITS_7
175#define CONFIG_KGDB_DEFBITS '7'
176#else /* CONFIG_KGDB_DEFBITS_8 */
177#define CONFIG_KGDB_DEFBITS '8'
178#endif
179
180/* SCI/UART settings, used in kgdb_console_setup() */
181int kgdb_portnum = CONFIG_KGDB_DEFPORT;
182EXPORT_SYMBOL_GPL(kgdb_portnum);
183int kgdb_baud = CONFIG_KGDB_DEFBAUD;
184EXPORT_SYMBOL_GPL(kgdb_baud);
185char kgdb_parity = CONFIG_KGDB_DEFPARITY;
186EXPORT_SYMBOL_GPL(kgdb_parity);
187char kgdb_bits = CONFIG_KGDB_DEFBITS;
188EXPORT_SYMBOL_GPL(kgdb_bits);
189
190/* Jump buffer for setjmp/longjmp */
191static jmp_buf rem_com_env;
192
193/* TRA differs sh3/4 */
194#if defined(CONFIG_CPU_SH3)
195#define TRA 0xffffffd0
196#elif defined(CONFIG_CPU_SH4)
197#define TRA 0xff000020
198#endif
199
200/* Macros for single step instruction identification */
201#define OPCODE_BT(op) (((op) & 0xff00) == 0x8900)
202#define OPCODE_BF(op) (((op) & 0xff00) == 0x8b00)
203#define OPCODE_BTF_DISP(op) (((op) & 0x80) ? (((op) | 0xffffff80) << 1) : \
204 (((op) & 0x7f ) << 1))
205#define OPCODE_BFS(op) (((op) & 0xff00) == 0x8f00)
206#define OPCODE_BTS(op) (((op) & 0xff00) == 0x8d00)
207#define OPCODE_BRA(op) (((op) & 0xf000) == 0xa000)
208#define OPCODE_BRA_DISP(op) (((op) & 0x800) ? (((op) | 0xfffff800) << 1) : \
209 (((op) & 0x7ff) << 1))
210#define OPCODE_BRAF(op) (((op) & 0xf0ff) == 0x0023)
211#define OPCODE_BRAF_REG(op) (((op) & 0x0f00) >> 8)
212#define OPCODE_BSR(op) (((op) & 0xf000) == 0xb000)
213#define OPCODE_BSR_DISP(op) (((op) & 0x800) ? (((op) | 0xfffff800) << 1) : \
214 (((op) & 0x7ff) << 1))
215#define OPCODE_BSRF(op) (((op) & 0xf0ff) == 0x0003)
216#define OPCODE_BSRF_REG(op) (((op) >> 8) & 0xf)
217#define OPCODE_JMP(op) (((op) & 0xf0ff) == 0x402b)
218#define OPCODE_JMP_REG(op) (((op) >> 8) & 0xf)
219#define OPCODE_JSR(op) (((op) & 0xf0ff) == 0x400b)
220#define OPCODE_JSR_REG(op) (((op) >> 8) & 0xf)
221#define OPCODE_RTS(op) ((op) == 0xb)
222#define OPCODE_RTE(op) ((op) == 0x2b)
223
224#define SR_T_BIT_MASK 0x1
225#define STEP_OPCODE 0xc320
226#define BIOS_CALL_TRAP 0x3f
227
228/* Exception codes as per SH-4 core manual */
229#define ADDRESS_ERROR_LOAD_VEC 7
230#define ADDRESS_ERROR_STORE_VEC 8
231#define TRAP_VEC 11
232#define INVALID_INSN_VEC 12
233#define INVALID_SLOT_VEC 13
234#define NMI_VEC 14
235#define USER_BREAK_VEC 15
236#define SERIAL_BREAK_VEC 58
237
238/* Misc static */
239static int stepped_address;
240static short stepped_opcode;
241static char in_buffer[BUFMAX];
242static char out_buffer[OUTBUFMAX];
243
244static void kgdb_to_gdb(const char *s);
245
246/* Convert ch to hex */
247static int hex(const char ch)
248{
249 if ((ch >= 'a') && (ch <= 'f'))
250 return (ch - 'a' + 10);
251 if ((ch >= '0') && (ch <= '9'))
252 return (ch - '0');
253 if ((ch >= 'A') && (ch <= 'F'))
254 return (ch - 'A' + 10);
255 return (-1);
256}
257
258/* Convert the memory pointed to by mem into hex, placing result in buf.
259 Returns a pointer to the last char put in buf (null) */
260static char *mem_to_hex(const char *mem, char *buf, const int count)
261{
262 int i;
263 int ch;
264 unsigned short s_val;
265 unsigned long l_val;
266
267 /* Check for 16 or 32 */
268 if (count == 2 && ((long) mem & 1) == 0) {
269 s_val = *(unsigned short *) mem;
270 mem = (char *) &s_val;
271 } else if (count == 4 && ((long) mem & 3) == 0) {
272 l_val = *(unsigned long *) mem;
273 mem = (char *) &l_val;
274 }
275 for (i = 0; i < count; i++) {
276 ch = *mem++;
277 buf = pack_hex_byte(buf, ch);
278 }
279 *buf = 0;
280 return (buf);
281}
282
283/* Convert the hex array pointed to by buf into binary, to be placed in mem.
284 Return a pointer to the character after the last byte written */
285static char *hex_to_mem(const char *buf, char *mem, const int count)
286{
287 int i;
288 unsigned char ch;
289
290 for (i = 0; i < count; i++) {
291 ch = hex(*buf++) << 4;
292 ch = ch + hex(*buf++);
293 *mem++ = ch;
294 }
295 return (mem);
296}
297
298/* While finding valid hex chars, convert to an integer, then return it */
299static int hex_to_int(char **ptr, int *int_value)
300{
301 int num_chars = 0;
302 int hex_value;
303
304 *int_value = 0;
305
306 while (**ptr) {
307 hex_value = hex(**ptr);
308 if (hex_value >= 0) {
309 *int_value = (*int_value << 4) | hex_value;
310 num_chars++;
311 } else
312 break;
313 (*ptr)++;
314 }
315 return num_chars;
316}
317
318/* Copy the binary array pointed to by buf into mem. Fix $, #,
319 and 0x7d escaped with 0x7d. Return a pointer to the character
320 after the last byte written. */
321static char *ebin_to_mem(const char *buf, char *mem, int count)
322{
323 for (; count > 0; count--, buf++) {
324 if (*buf == 0x7d)
325 *mem++ = *(++buf) ^ 0x20;
326 else
327 *mem++ = *buf;
328 }
329 return mem;
330}
331
332/* Scan for the start char '$', read the packet and check the checksum */
333static void get_packet(char *buffer, int buflen)
334{
335 unsigned char checksum;
336 unsigned char xmitcsum;
337 int i;
338 int count;
339 char ch;
340
341 do {
342 /* Ignore everything until the start character */
343 while ((ch = get_debug_char()) != '$');
344
345 checksum = 0;
346 xmitcsum = -1;
347 count = 0;
348
349 /* Now, read until a # or end of buffer is found */
350 while (count < (buflen - 1)) {
351 ch = get_debug_char();
352
353 if (ch == '#')
354 break;
355
356 checksum = checksum + ch;
357 buffer[count] = ch;
358 count = count + 1;
359 }
360
361 buffer[count] = 0;
362
363 /* Continue to read checksum following # */
364 if (ch == '#') {
365 xmitcsum = hex(get_debug_char()) << 4;
366 xmitcsum += hex(get_debug_char());
367
368 /* Checksum */
369 if (checksum != xmitcsum)
370 put_debug_char('-'); /* Failed checksum */
371 else {
372 /* Ack successful transfer */
373 put_debug_char('+');
374
375 /* If a sequence char is present, reply
376 the sequence ID */
377 if (buffer[2] == ':') {
378 put_debug_char(buffer[0]);
379 put_debug_char(buffer[1]);
380
381 /* Remove sequence chars from buffer */
382 count = strlen(buffer);
383 for (i = 3; i <= count; i++)
384 buffer[i - 3] = buffer[i];
385 }
386 }
387 }
388 }
389 while (checksum != xmitcsum); /* Keep trying while we fail */
390}
391
392/* Send the packet in the buffer with run-length encoding */
393static void put_packet(char *buffer)
394{
395 int checksum;
396 char *src;
397 int runlen;
398 int encode;
399
400 do {
401 src = buffer;
402 put_debug_char('$');
403 checksum = 0;
404
405 /* Continue while we still have chars left */
406 while (*src) {
407 /* Check for runs up to 99 chars long */
408 for (runlen = 1; runlen < 99; runlen++) {
409 if (src[0] != src[runlen])
410 break;
411 }
412
413 if (runlen > 3) {
414 /* Got a useful amount, send encoding */
415 encode = runlen + ' ' - 4;
416 put_debug_char(*src); checksum += *src;
417 put_debug_char('*'); checksum += '*';
418 put_debug_char(encode); checksum += encode;
419 src += runlen;
420 } else {
421 /* Otherwise just send the current char */
422 put_debug_char(*src); checksum += *src;
423 src += 1;
424 }
425 }
426
427 /* '#' Separator, put high and low components of checksum */
428 put_debug_char('#');
429 put_debug_char(hex_asc_hi(checksum));
430 put_debug_char(hex_asc_lo(checksum));
431 }
432 while ((get_debug_char()) != '+'); /* While no ack */
433}
434
435/* A bus error has occurred - perform a longjmp to return execution and
436 allow handling of the error */
437static void kgdb_handle_bus_error(void)
438{
439 longjmp(rem_com_env, 1);
440}
441
442/* Translate SH-3/4 exception numbers to unix-like signal values */
443static int compute_signal(const int excep_code)
444{
445 int sigval;
446
447 switch (excep_code) {
448
449 case INVALID_INSN_VEC:
450 case INVALID_SLOT_VEC:
451 sigval = SIGILL;
452 break;
453 case ADDRESS_ERROR_LOAD_VEC:
454 case ADDRESS_ERROR_STORE_VEC:
455 sigval = SIGSEGV;
456 break;
457
458 case SERIAL_BREAK_VEC:
459 case NMI_VEC:
460 sigval = SIGINT;
461 break;
462
463 case USER_BREAK_VEC:
464 case TRAP_VEC:
465 sigval = SIGTRAP;
466 break;
467
468 default:
469 sigval = SIGBUS; /* "software generated" */
470 break;
471 }
472
473 return (sigval);
474}
475
476/* Make a local copy of the registers passed into the handler (bletch) */
477static void kgdb_regs_to_gdb_regs(const struct kgdb_regs *regs,
478 int *gdb_regs)
479{
480 gdb_regs[R0] = regs->regs[R0];
481 gdb_regs[R1] = regs->regs[R1];
482 gdb_regs[R2] = regs->regs[R2];
483 gdb_regs[R3] = regs->regs[R3];
484 gdb_regs[R4] = regs->regs[R4];
485 gdb_regs[R5] = regs->regs[R5];
486 gdb_regs[R6] = regs->regs[R6];
487 gdb_regs[R7] = regs->regs[R7];
488 gdb_regs[R8] = regs->regs[R8];
489 gdb_regs[R9] = regs->regs[R9];
490 gdb_regs[R10] = regs->regs[R10];
491 gdb_regs[R11] = regs->regs[R11];
492 gdb_regs[R12] = regs->regs[R12];
493 gdb_regs[R13] = regs->regs[R13];
494 gdb_regs[R14] = regs->regs[R14];
495 gdb_regs[R15] = regs->regs[R15];
496 gdb_regs[PC] = regs->pc;
497 gdb_regs[PR] = regs->pr;
498 gdb_regs[GBR] = regs->gbr;
499 gdb_regs[MACH] = regs->mach;
500 gdb_regs[MACL] = regs->macl;
501 gdb_regs[SR] = regs->sr;
502 gdb_regs[VBR] = regs->vbr;
503}
504
505/* Copy local gdb registers back to kgdb regs, for later copy to kernel */
506static void gdb_regs_to_kgdb_regs(const int *gdb_regs,
507 struct kgdb_regs *regs)
508{
509 regs->regs[R0] = gdb_regs[R0];
510 regs->regs[R1] = gdb_regs[R1];
511 regs->regs[R2] = gdb_regs[R2];
512 regs->regs[R3] = gdb_regs[R3];
513 regs->regs[R4] = gdb_regs[R4];
514 regs->regs[R5] = gdb_regs[R5];
515 regs->regs[R6] = gdb_regs[R6];
516 regs->regs[R7] = gdb_regs[R7];
517 regs->regs[R8] = gdb_regs[R8];
518 regs->regs[R9] = gdb_regs[R9];
519 regs->regs[R10] = gdb_regs[R10];
520 regs->regs[R11] = gdb_regs[R11];
521 regs->regs[R12] = gdb_regs[R12];
522 regs->regs[R13] = gdb_regs[R13];
523 regs->regs[R14] = gdb_regs[R14];
524 regs->regs[R15] = gdb_regs[R15];
525 regs->pc = gdb_regs[PC];
526 regs->pr = gdb_regs[PR];
527 regs->gbr = gdb_regs[GBR];
528 regs->mach = gdb_regs[MACH];
529 regs->macl = gdb_regs[MACL];
530 regs->sr = gdb_regs[SR];
531 regs->vbr = gdb_regs[VBR];
532}
533
534/* Calculate the new address for after a step */
535static short *get_step_address(void)
536{
537 short op = *(short *) trap_registers.pc;
538 long addr;
539
540 /* BT */
541 if (OPCODE_BT(op)) {
542 if (trap_registers.sr & SR_T_BIT_MASK)
543 addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op);
544 else
545 addr = trap_registers.pc + 2;
546 }
547
548 /* BTS */
549 else if (OPCODE_BTS(op)) {
550 if (trap_registers.sr & SR_T_BIT_MASK)
551 addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op);
552 else
553 addr = trap_registers.pc + 4; /* Not in delay slot */
554 }
555
556 /* BF */
557 else if (OPCODE_BF(op)) {
558 if (!(trap_registers.sr & SR_T_BIT_MASK))
559 addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op);
560 else
561 addr = trap_registers.pc + 2;
562 }
563
564 /* BFS */
565 else if (OPCODE_BFS(op)) {
566 if (!(trap_registers.sr & SR_T_BIT_MASK))
567 addr = trap_registers.pc + 4 + OPCODE_BTF_DISP(op);
568 else
569 addr = trap_registers.pc + 4; /* Not in delay slot */
570 }
571
572 /* BRA */
573 else if (OPCODE_BRA(op))
574 addr = trap_registers.pc + 4 + OPCODE_BRA_DISP(op);
575
576 /* BRAF */
577 else if (OPCODE_BRAF(op))
578 addr = trap_registers.pc + 4
579 + trap_registers.regs[OPCODE_BRAF_REG(op)];
580
581 /* BSR */
582 else if (OPCODE_BSR(op))
583 addr = trap_registers.pc + 4 + OPCODE_BSR_DISP(op);
584
585 /* BSRF */
586 else if (OPCODE_BSRF(op))
587 addr = trap_registers.pc + 4
588 + trap_registers.regs[OPCODE_BSRF_REG(op)];
589
590 /* JMP */
591 else if (OPCODE_JMP(op))
592 addr = trap_registers.regs[OPCODE_JMP_REG(op)];
593
594 /* JSR */
595 else if (OPCODE_JSR(op))
596 addr = trap_registers.regs[OPCODE_JSR_REG(op)];
597
598 /* RTS */
599 else if (OPCODE_RTS(op))
600 addr = trap_registers.pr;
601
602 /* RTE */
603 else if (OPCODE_RTE(op))
604 addr = trap_registers.regs[15];
605
606 /* Other */
607 else
608 addr = trap_registers.pc + 2;
609
610 flush_icache_range(addr, addr + 2);
611 return (short *) addr;
612}
613
614/* Set up a single-step. Replace the instruction immediately after the
615 current instruction (i.e. next in the expected flow of control) with a
616 trap instruction, so that returning will cause only a single instruction
617 to be executed. Note that this model is slightly broken for instructions
618 with delay slots (e.g. B[TF]S, BSR, BRA etc), where both the branch
619 and the instruction in the delay slot will be executed. */
620static void do_single_step(void)
621{
622 unsigned short *addr = 0;
623
624 /* Determine where the target instruction will send us to */
625 addr = get_step_address();
626 stepped_address = (int)addr;
627
628 /* Replace it */
629 stepped_opcode = *(short *)addr;
630 *addr = STEP_OPCODE;
631
632 /* Flush and return */
633 flush_icache_range((long) addr, (long) addr + 2);
634}
635
636/* Undo a single step */
637static void undo_single_step(void)
638{
639 /* If we have stepped, put back the old instruction */
640 /* Use stepped_address in case we stopped elsewhere */
641 if (stepped_opcode != 0) {
642 *(short*)stepped_address = stepped_opcode;
643 flush_icache_range(stepped_address, stepped_address + 2);
644 }
645 stepped_opcode = 0;
646}
647
648/* Send a signal message */
649static void send_signal_msg(const int signum)
650{
651 out_buffer[0] = 'S';
652 out_buffer[1] = hex_asc_hi(signum);
653 out_buffer[2] = hex_asc_lo(signum);
654 out_buffer[3] = 0;
655 put_packet(out_buffer);
656}
657
658/* Reply that all was well */
659static void send_ok_msg(void)
660{
661 strcpy(out_buffer, "OK");
662 put_packet(out_buffer);
663}
664
665/* Reply that an error occurred */
666static void send_err_msg(void)
667{
668 strcpy(out_buffer, "E01");
669 put_packet(out_buffer);
670}
671
672/* Empty message indicates unrecognised command */
673static void send_empty_msg(void)
674{
675 put_packet("");
676}
677
678/* Read memory due to 'm' message */
679static void read_mem_msg(void)
680{
681 char *ptr;
682 int addr;
683 int length;
684
685 /* Jmp, disable bus error handler */
686 if (setjmp(rem_com_env) == 0) {
687
688 kgdb_nofault = 1;
689
690 /* Walk through, have m<addr>,<length> */
691 ptr = &in_buffer[1];
692 if (hex_to_int(&ptr, &addr) && (*ptr++ == ','))
693 if (hex_to_int(&ptr, &length)) {
694 ptr = 0;
695 if (length * 2 > OUTBUFMAX)
696 length = OUTBUFMAX / 2;
697 mem_to_hex((char *) addr, out_buffer, length);
698 }
699 if (ptr)
700 send_err_msg();
701 else
702 put_packet(out_buffer);
703 } else
704 send_err_msg();
705
706 /* Restore bus error handler */
707 kgdb_nofault = 0;
708}
709
710/* Write memory due to 'M' or 'X' message */
711static void write_mem_msg(int binary)
712{
713 char *ptr;
714 int addr;
715 int length;
716
717 if (setjmp(rem_com_env) == 0) {
718
719 kgdb_nofault = 1;
720
721 /* Walk through, have M<addr>,<length>:<data> */
722 ptr = &in_buffer[1];
723 if (hex_to_int(&ptr, &addr) && (*ptr++ == ','))
724 if (hex_to_int(&ptr, &length) && (*ptr++ == ':')) {
725 if (binary)
726 ebin_to_mem(ptr, (char*)addr, length);
727 else
728 hex_to_mem(ptr, (char*)addr, length);
729 flush_icache_range(addr, addr + length);
730 ptr = 0;
731 send_ok_msg();
732 }
733 if (ptr)
734 send_err_msg();
735 } else
736 send_err_msg();
737
738 /* Restore bus error handler */
739 kgdb_nofault = 0;
740}
741
742/* Continue message */
743static void continue_msg(void)
744{
745 /* Try to read optional parameter, PC unchanged if none */
746 char *ptr = &in_buffer[1];
747 int addr;
748
749 if (hex_to_int(&ptr, &addr))
750 trap_registers.pc = addr;
751}
752
753/* Continue message with signal */
754static void continue_with_sig_msg(void)
755{
756 int signal;
757 char *ptr = &in_buffer[1];
758 int addr;
759
760 /* Report limitation */
761 kgdb_to_gdb("Cannot force signal in kgdb, continuing anyway.\n");
762
763 /* Signal */
764 hex_to_int(&ptr, &signal);
765 if (*ptr == ';')
766 ptr++;
767
768 /* Optional address */
769 if (hex_to_int(&ptr, &addr))
770 trap_registers.pc = addr;
771}
772
773/* Step message */
774static void step_msg(void)
775{
776 continue_msg();
777 do_single_step();
778}
779
780/* Step message with signal */
781static void step_with_sig_msg(void)
782{
783 continue_with_sig_msg();
784 do_single_step();
785}
786
787/* Send register contents */
788static void send_regs_msg(void)
789{
790 kgdb_regs_to_gdb_regs(&trap_registers, registers);
791 mem_to_hex((char *) registers, out_buffer, NUMREGBYTES);
792 put_packet(out_buffer);
793}
794
795/* Set register contents - currently can't set other thread's registers */
796static void set_regs_msg(void)
797{
798 kgdb_regs_to_gdb_regs(&trap_registers, registers);
799 hex_to_mem(&in_buffer[1], (char *) registers, NUMREGBYTES);
800 gdb_regs_to_kgdb_regs(registers, &trap_registers);
801 send_ok_msg();
802}
803
804#ifdef CONFIG_SH_KGDB_CONSOLE
805/*
806 * Bring up the ports..
807 */
808static int __init kgdb_serial_setup(void)
809{
810 struct console dummy;
811 return kgdb_console_setup(&dummy, 0);
812}
813#else
814#define kgdb_serial_setup() 0
815#endif
816
817/* The command loop, read and act on requests */
818static void kgdb_command_loop(const int excep_code, const int trapa_value)
819{
820 int sigval;
821
822 /* Enter GDB mode (e.g. after detach) */
823 if (!kgdb_in_gdb_mode) {
824 /* Do serial setup, notify user, issue preemptive ack */
825 printk(KERN_NOTICE "KGDB: Waiting for GDB\n");
826 kgdb_in_gdb_mode = 1;
827 put_debug_char('+');
828 }
829
830 /* Reply to host that an exception has occurred */
831 sigval = compute_signal(excep_code);
832 send_signal_msg(sigval);
833
834 /* TRAP_VEC exception indicates a software trap inserted in place of
835 code by GDB so back up PC by one instruction, as this instruction
836 will later be replaced by its original one. Do NOT do this for
837 trap 0xff, since that indicates a compiled-in breakpoint which
838 will not be replaced (and we would retake the trap forever) */
839 if ((excep_code == TRAP_VEC) && (trapa_value != (0x3c << 2)))
840 trap_registers.pc -= 2;
841
842 /* Undo any stepping we may have done */
843 undo_single_step();
844
845 while (1) {
846 out_buffer[0] = 0;
847 get_packet(in_buffer, BUFMAX);
848
849 /* Examine first char of buffer to see what we need to do */
850 switch (in_buffer[0]) {
851 case '?': /* Send which signal we've received */
852 send_signal_msg(sigval);
853 break;
854
855 case 'g': /* Return the values of the CPU registers */
856 send_regs_msg();
857 break;
858
859 case 'G': /* Set the value of the CPU registers */
860 set_regs_msg();
861 break;
862
863 case 'm': /* Read LLLL bytes address AA..AA */
864 read_mem_msg();
865 break;
866
867 case 'M': /* Write LLLL bytes address AA..AA, ret OK */
868 write_mem_msg(0); /* 0 = data in hex */
869 break;
870
871 case 'X': /* Write LLLL bytes esc bin address AA..AA */
872 if (kgdb_bits == '8')
873 write_mem_msg(1); /* 1 = data in binary */
874 else
875 send_empty_msg();
876 break;
877
878 case 'C': /* Continue, signum included, we ignore it */
879 continue_with_sig_msg();
880 return;
881
882 case 'c': /* Continue at address AA..AA (optional) */
883 continue_msg();
884 return;
885
886 case 'S': /* Step, signum included, we ignore it */
887 step_with_sig_msg();
888 return;
889
890 case 's': /* Step one instruction from AA..AA */
891 step_msg();
892 return;
893
894 case 'k': /* 'Kill the program' with a kernel ? */
895 break;
896
897 case 'D': /* Detach from program, send reply OK */
898 kgdb_in_gdb_mode = 0;
899 send_ok_msg();
900 get_debug_char();
901 return;
902
903 default:
904 send_empty_msg();
905 break;
906 }
907 }
908}
909
910/* There has been an exception, most likely a breakpoint. */
911static void handle_exception(struct pt_regs *regs)
912{
913 int excep_code, vbr_val;
914 int count;
915 int trapa_value = ctrl_inl(TRA);
916
917 /* Copy kernel regs (from stack) */
918 for (count = 0; count < 16; count++)
919 trap_registers.regs[count] = regs->regs[count];
920 trap_registers.pc = regs->pc;
921 trap_registers.pr = regs->pr;
922 trap_registers.sr = regs->sr;
923 trap_registers.gbr = regs->gbr;
924 trap_registers.mach = regs->mach;
925 trap_registers.macl = regs->macl;
926
927 asm("stc vbr, %0":"=r"(vbr_val));
928 trap_registers.vbr = vbr_val;
929
930 /* Get excode for command loop call, user access */
931 asm("stc r2_bank, %0":"=r"(excep_code));
932
933 /* Act on the exception */
934 kgdb_command_loop(excep_code, trapa_value);
935
936 /* Copy back the (maybe modified) registers */
937 for (count = 0; count < 16; count++)
938 regs->regs[count] = trap_registers.regs[count];
939 regs->pc = trap_registers.pc;
940 regs->pr = trap_registers.pr;
941 regs->sr = trap_registers.sr;
942 regs->gbr = trap_registers.gbr;
943 regs->mach = trap_registers.mach;
944 regs->macl = trap_registers.macl;
945
946 vbr_val = trap_registers.vbr;
947 asm("ldc %0, vbr": :"r"(vbr_val));
948}
949
950asmlinkage void kgdb_handle_exception(unsigned long r4, unsigned long r5,
951 unsigned long r6, unsigned long r7,
952 struct pt_regs __regs)
953{
954 struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
955 handle_exception(regs);
956}
957
958/* Initialise the KGDB data structures and serial configuration */
959int __init kgdb_init(void)
960{
961 in_nmi = 0;
962 kgdb_nofault = 0;
963 stepped_opcode = 0;
964 kgdb_in_gdb_mode = 0;
965
966 if (kgdb_serial_setup() != 0) {
967 printk(KERN_NOTICE "KGDB: serial setup error\n");
968 return -1;
969 }
970
971 /* Init ptr to exception handler */
972 kgdb_debug_hook = handle_exception;
973 kgdb_bus_err_hook = kgdb_handle_bus_error;
974
975 /* Enter kgdb now if requested, or just report init done */
976 printk(KERN_NOTICE "KGDB: stub is initialized.\n");
977
978 return 0;
979}
980
981/* Make function available for "user messages"; console will use it too. */
982
983char gdbmsgbuf[BUFMAX];
984#define MAXOUT ((BUFMAX-2)/2)
985
986static void kgdb_msg_write(const char *s, unsigned count)
987{
988 int i;
989 int wcount;
990 char *bufptr;
991
992 /* 'O'utput */
993 gdbmsgbuf[0] = 'O';
994
995 /* Fill and send buffers... */
996 while (count > 0) {
997 bufptr = gdbmsgbuf + 1;
998
999 /* Calculate how many this time */
1000 wcount = (count > MAXOUT) ? MAXOUT : count;
1001
1002 /* Pack in hex chars */
1003 for (i = 0; i < wcount; i++)
1004 bufptr = pack_hex_byte(bufptr, s[i]);
1005 *bufptr = '\0';
1006
1007 /* Move up */
1008 s += wcount;
1009 count -= wcount;
1010
1011 /* Write packet */
1012 put_packet(gdbmsgbuf);
1013 }
1014}
1015
1016static void kgdb_to_gdb(const char *s)
1017{
1018 kgdb_msg_write(s, strlen(s));
1019}
1020
1021#ifdef CONFIG_SH_KGDB_CONSOLE
1022void kgdb_console_write(struct console *co, const char *s, unsigned count)
1023{
1024 /* Bail if we're not talking to GDB */
1025 if (!kgdb_in_gdb_mode)
1026 return;
1027
1028 kgdb_msg_write(s, count);
1029}
1030#endif
1031
1032#ifdef CONFIG_KGDB_SYSRQ
1033static void sysrq_handle_gdb(int key, struct tty_struct *tty)
1034{
1035 printk("Entering GDB stub\n");
1036 breakpoint();
1037}
1038
1039static struct sysrq_key_op sysrq_gdb_op = {
1040 .handler = sysrq_handle_gdb,
1041 .help_msg = "Gdb",
1042 .action_msg = "GDB",
1043};
1044
1045static int gdb_register_sysrq(void)
1046{
1047 printk("Registering GDB sysrq handler\n");
1048 register_sysrq_key('g', &sysrq_gdb_op);
1049 return 0;
1050}
1051module_init(gdb_register_sysrq);
1052#endif
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