1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * kgdbts is a test suite for kgdb for the sole purpose of validating
4  * that key pieces of the kgdb internals are working properly such as
5  * HW/SW breakpoints, single stepping, and NMI.
6  *
7  * Created by: Jason Wessel <jason.wessel@windriver.com>
8  *
9  * Copyright (c) 2008 Wind River Systems, Inc.
10  */
11 /* Information about the kgdb test suite.
12  * -------------------------------------
13  *
14  * The kgdb test suite is designed as a KGDB I/O module which
15  * simulates the communications that a debugger would have with kgdb.
16  * The tests are broken up in to a line by line and referenced here as
17  * a "get" which is kgdb requesting input and "put" which is kgdb
18  * sending a response.
19  *
20  * The kgdb suite can be invoked from the kernel command line
21  * arguments system or executed dynamically at run time.  The test
22  * suite uses the variable "kgdbts" to obtain the information about
23  * which tests to run and to configure the verbosity level.  The
24  * following are the various characters you can use with the kgdbts=
25  * line:
26  *
27  * When using the "kgdbts=" you only choose one of the following core
28  * test types:
29  * A = Run all the core tests silently
30  * V1 = Run all the core tests with minimal output
31  * V2 = Run all the core tests in debug mode
32  *
33  * You can also specify optional tests:
34  * N## = Go to sleep with interrupts of for ## seconds
35  *       to test the HW NMI watchdog
36  * F## = Break at kernel_clone for ## iterations
37  * S## = Break at sys_open for ## iterations
38  * I## = Run the single step test ## iterations
39  *
40  * NOTE: that the kernel_clone and sys_open tests are mutually exclusive.
41  *
42  * To invoke the kgdb test suite from boot you use a kernel start
43  * argument as follows:
44  * 	kgdbts=V1 kgdbwait
45  * Or if you wanted to perform the NMI test for 6 seconds and kernel_clone
46  * test for 100 forks, you could use:
47  * 	kgdbts=V1N6F100 kgdbwait
48  *
49  * The test suite can also be invoked at run time with:
50  *	echo kgdbts=V1N6F100 > /sys/module/kgdbts/parameters/kgdbts
51  * Or as another example:
52  *	echo kgdbts=V2 > /sys/module/kgdbts/parameters/kgdbts
53  *
54  * When developing a new kgdb arch specific implementation or
55  * using these tests for the purpose of regression testing,
56  * several invocations are required.
57  *
58  * 1) Boot with the test suite enabled by using the kernel arguments
59  *       "kgdbts=V1F100 kgdbwait"
60  *    ## If kgdb arch specific implementation has NMI use
61  *       "kgdbts=V1N6F100
62  *
63  * 2) After the system boot run the basic test.
64  * echo kgdbts=V1 > /sys/module/kgdbts/parameters/kgdbts
65  *
66  * 3) Run the concurrency tests.  It is best to use n+1
67  *    while loops where n is the number of cpus you have
68  *    in your system.  The example below uses only two
69  *    loops.
70  *
71  * ## This tests break points on sys_open
72  * while [ 1 ] ; do find / > /dev/null 2>&1 ; done &
73  * while [ 1 ] ; do find / > /dev/null 2>&1 ; done &
74  * echo kgdbts=V1S10000 > /sys/module/kgdbts/parameters/kgdbts
75  * fg # and hit control-c
76  * fg # and hit control-c
77  * ## This tests break points on kernel_clone
78  * while [ 1 ] ; do date > /dev/null ; done &
79  * while [ 1 ] ; do date > /dev/null ; done &
80  * echo kgdbts=V1F1000 > /sys/module/kgdbts/parameters/kgdbts
81  * fg # and hit control-c
82  *
83  */
84 
85 #include <linux/kernel.h>
86 #include <linux/kgdb.h>
87 #include <linux/ctype.h>
88 #include <linux/uaccess.h>
89 #include <linux/syscalls.h>
90 #include <linux/nmi.h>
91 #include <linux/delay.h>
92 #include <linux/kthread.h>
93 #include <linux/module.h>
94 #include <linux/sched/task.h>
95 #include <linux/kallsyms.h>
96 
97 #include <asm/sections.h>
98 
99 #define v1printk(a...) do {		\
100 	if (verbose)			\
101 		printk(KERN_INFO a);	\
102 } while (0)
103 #define v2printk(a...) do {		\
104 	if (verbose > 1) {		\
105 		printk(KERN_INFO a);	\
106 	}				\
107 	touch_nmi_watchdog();		\
108 } while (0)
109 #define eprintk(a...) do {		\
110 	printk(KERN_ERR a);		\
111 	WARN_ON(1);			\
112 } while (0)
113 #define MAX_CONFIG_LEN		40
114 
115 static struct kgdb_io kgdbts_io_ops;
116 static char get_buf[BUFMAX];
117 static int get_buf_cnt;
118 static char put_buf[BUFMAX];
119 static int put_buf_cnt;
120 static char scratch_buf[BUFMAX];
121 static int verbose;
122 static int repeat_test;
123 static int test_complete;
124 static int send_ack;
125 static int final_ack;
126 static int force_hwbrks;
127 static int hwbreaks_ok;
128 static int hw_break_val;
129 static int hw_break_val2;
130 static int cont_instead_of_sstep;
131 static unsigned long cont_thread_id;
132 static unsigned long sstep_thread_id;
133 #if defined(CONFIG_ARM) || defined(CONFIG_MIPS) || defined(CONFIG_SPARC)
134 static int arch_needs_sstep_emulation = 1;
135 #else
136 static int arch_needs_sstep_emulation;
137 #endif
138 static unsigned long cont_addr;
139 static unsigned long sstep_addr;
140 static int restart_from_top_after_write;
141 static int sstep_state;
142 
143 /* Storage for the registers, in GDB format. */
144 static unsigned long kgdbts_gdb_regs[(NUMREGBYTES +
145 					sizeof(unsigned long) - 1) /
146 					sizeof(unsigned long)];
147 static struct pt_regs kgdbts_regs;
148 
149 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
150 static int configured		= -1;
151 
152 #ifdef CONFIG_KGDB_TESTS_BOOT_STRING
153 static char config[MAX_CONFIG_LEN] = CONFIG_KGDB_TESTS_BOOT_STRING;
154 #else
155 static char config[MAX_CONFIG_LEN];
156 #endif
157 static struct kparam_string kps = {
158 	.string			= config,
159 	.maxlen			= MAX_CONFIG_LEN,
160 };
161 
162 static void fill_get_buf(char *buf);
163 
164 struct test_struct {
165 	char *get;
166 	char *put;
167 	void (*get_handler)(char *);
168 	int (*put_handler)(char *, char *);
169 };
170 
171 struct test_state {
172 	char *name;
173 	struct test_struct *tst;
174 	int idx;
175 	int (*run_test) (int, int);
176 	int (*validate_put) (char *);
177 };
178 
179 static struct test_state ts;
180 
kgdbts_unreg_thread(void * ptr)181 static int kgdbts_unreg_thread(void *ptr)
182 {
183 	/* Wait until the tests are complete and then ungresiter the I/O
184 	 * driver.
185 	 */
186 	while (!final_ack)
187 		msleep_interruptible(1500);
188 	/* Pause for any other threads to exit after final ack. */
189 	msleep_interruptible(1000);
190 	if (configured)
191 		kgdb_unregister_io_module(&kgdbts_io_ops);
192 	configured = 0;
193 
194 	return 0;
195 }
196 
197 /* This is noinline such that it can be used for a single location to
198  * place a breakpoint
199  */
kgdbts_break_test(void)200 static noinline void kgdbts_break_test(void)
201 {
202 	v2printk("kgdbts: breakpoint complete\n");
203 }
204 
205 /*
206  * This is a cached wrapper for kallsyms_lookup_name().
207  *
208  * The cache is a big win for several tests. For example it more the doubles
209  * the cycles per second during the sys_open test. This is not theoretic,
210  * the performance improvement shows up at human scale, especially when
211  * testing using emulators.
212  *
213  * Obviously neither re-entrant nor thread-safe but that is OK since it
214  * can only be called from the debug trap (and therefore all other CPUs
215  * are halted).
216  */
lookup_addr(char * arg)217 static unsigned long lookup_addr(char *arg)
218 {
219 	static char cached_arg[KSYM_NAME_LEN];
220 	static unsigned long cached_addr;
221 
222 	if (strcmp(arg, cached_arg)) {
223 		strscpy(cached_arg, arg, KSYM_NAME_LEN);
224 		cached_addr = kallsyms_lookup_name(arg);
225 	}
226 
227 	return (unsigned long)dereference_function_descriptor(
228 			(void *)cached_addr);
229 }
230 
break_helper(char * bp_type,char * arg,unsigned long vaddr)231 static void break_helper(char *bp_type, char *arg, unsigned long vaddr)
232 {
233 	unsigned long addr;
234 
235 	if (arg)
236 		addr = lookup_addr(arg);
237 	else
238 		addr = vaddr;
239 
240 	sprintf(scratch_buf, "%s,%lx,%i", bp_type, addr,
241 		BREAK_INSTR_SIZE);
242 	fill_get_buf(scratch_buf);
243 }
244 
sw_break(char * arg)245 static void sw_break(char *arg)
246 {
247 	break_helper(force_hwbrks ? "Z1" : "Z0", arg, 0);
248 }
249 
sw_rem_break(char * arg)250 static void sw_rem_break(char *arg)
251 {
252 	break_helper(force_hwbrks ? "z1" : "z0", arg, 0);
253 }
254 
hw_break(char * arg)255 static void hw_break(char *arg)
256 {
257 	break_helper("Z1", arg, 0);
258 }
259 
hw_rem_break(char * arg)260 static void hw_rem_break(char *arg)
261 {
262 	break_helper("z1", arg, 0);
263 }
264 
hw_write_break(char * arg)265 static void hw_write_break(char *arg)
266 {
267 	break_helper("Z2", arg, 0);
268 }
269 
hw_rem_write_break(char * arg)270 static void hw_rem_write_break(char *arg)
271 {
272 	break_helper("z2", arg, 0);
273 }
274 
hw_access_break(char * arg)275 static void hw_access_break(char *arg)
276 {
277 	break_helper("Z4", arg, 0);
278 }
279 
hw_rem_access_break(char * arg)280 static void hw_rem_access_break(char *arg)
281 {
282 	break_helper("z4", arg, 0);
283 }
284 
hw_break_val_access(void)285 static void hw_break_val_access(void)
286 {
287 	hw_break_val2 = hw_break_val;
288 }
289 
hw_break_val_write(void)290 static void hw_break_val_write(void)
291 {
292 	hw_break_val++;
293 }
294 
get_thread_id_continue(char * put_str,char * arg)295 static int get_thread_id_continue(char *put_str, char *arg)
296 {
297 	char *ptr = &put_str[11];
298 
299 	if (put_str[1] != 'T' || put_str[2] != '0')
300 		return 1;
301 	kgdb_hex2long(&ptr, &cont_thread_id);
302 	return 0;
303 }
304 
check_and_rewind_pc(char * put_str,char * arg)305 static int check_and_rewind_pc(char *put_str, char *arg)
306 {
307 	unsigned long addr = lookup_addr(arg);
308 	unsigned long ip;
309 	int offset = 0;
310 
311 	kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs,
312 		 NUMREGBYTES);
313 	gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
314 	ip = instruction_pointer(&kgdbts_regs);
315 	v2printk("Stopped at IP: %lx\n", ip);
316 #ifdef GDB_ADJUSTS_BREAK_OFFSET
317 	/* On some arches, a breakpoint stop requires it to be decremented */
318 	if (addr + BREAK_INSTR_SIZE == ip)
319 		offset = -BREAK_INSTR_SIZE;
320 #endif
321 
322 	if (arch_needs_sstep_emulation && sstep_addr &&
323 	    ip + offset == sstep_addr &&
324 	    ((!strcmp(arg, "do_sys_openat2") || !strcmp(arg, "kernel_clone")))) {
325 		/* This is special case for emulated single step */
326 		v2printk("Emul: rewind hit single step bp\n");
327 		restart_from_top_after_write = 1;
328 	} else if (strcmp(arg, "silent") && ip + offset != addr) {
329 		eprintk("kgdbts: BP mismatch %lx expected %lx\n",
330 			   ip + offset, addr);
331 		return 1;
332 	}
333 	/* Readjust the instruction pointer if needed */
334 	ip += offset;
335 	cont_addr = ip;
336 #ifdef GDB_ADJUSTS_BREAK_OFFSET
337 	instruction_pointer_set(&kgdbts_regs, ip);
338 #endif
339 	return 0;
340 }
341 
check_single_step(char * put_str,char * arg)342 static int check_single_step(char *put_str, char *arg)
343 {
344 	unsigned long addr = lookup_addr(arg);
345 	static int matched_id;
346 
347 	/*
348 	 * From an arch indepent point of view the instruction pointer
349 	 * should be on a different instruction
350 	 */
351 	kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs,
352 		 NUMREGBYTES);
353 	gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
354 	v2printk("Singlestep stopped at IP: %lx\n",
355 		   instruction_pointer(&kgdbts_regs));
356 
357 	if (sstep_thread_id != cont_thread_id) {
358 		/*
359 		 * Ensure we stopped in the same thread id as before, else the
360 		 * debugger should continue until the original thread that was
361 		 * single stepped is scheduled again, emulating gdb's behavior.
362 		 */
363 		v2printk("ThrID does not match: %lx\n", cont_thread_id);
364 		if (arch_needs_sstep_emulation) {
365 			if (matched_id &&
366 			    instruction_pointer(&kgdbts_regs) != addr)
367 				goto continue_test;
368 			matched_id++;
369 			ts.idx -= 2;
370 			sstep_state = 0;
371 			return 0;
372 		}
373 		cont_instead_of_sstep = 1;
374 		ts.idx -= 4;
375 		return 0;
376 	}
377 continue_test:
378 	matched_id = 0;
379 	if (instruction_pointer(&kgdbts_regs) == addr) {
380 		eprintk("kgdbts: SingleStep failed at %lx\n",
381 			   instruction_pointer(&kgdbts_regs));
382 		return 1;
383 	}
384 
385 	return 0;
386 }
387 
write_regs(char * arg)388 static void write_regs(char *arg)
389 {
390 	memset(scratch_buf, 0, sizeof(scratch_buf));
391 	scratch_buf[0] = 'G';
392 	pt_regs_to_gdb_regs(kgdbts_gdb_regs, &kgdbts_regs);
393 	kgdb_mem2hex((char *)kgdbts_gdb_regs, &scratch_buf[1], NUMREGBYTES);
394 	fill_get_buf(scratch_buf);
395 }
396 
skip_back_repeat_test(char * arg)397 static void skip_back_repeat_test(char *arg)
398 {
399 	int go_back = simple_strtol(arg, NULL, 10);
400 
401 	repeat_test--;
402 	if (repeat_test <= 0) {
403 		ts.idx++;
404 	} else {
405 		if (repeat_test % 100 == 0)
406 			v1printk("kgdbts:RUN ... %d remaining\n", repeat_test);
407 
408 		ts.idx -= go_back;
409 	}
410 	fill_get_buf(ts.tst[ts.idx].get);
411 }
412 
got_break(char * put_str,char * arg)413 static int got_break(char *put_str, char *arg)
414 {
415 	test_complete = 1;
416 	if (!strncmp(put_str+1, arg, 2)) {
417 		if (!strncmp(arg, "T0", 2))
418 			test_complete = 2;
419 		return 0;
420 	}
421 	return 1;
422 }
423 
get_cont_catch(char * arg)424 static void get_cont_catch(char *arg)
425 {
426 	/* Always send detach because the test is completed at this point */
427 	fill_get_buf("D");
428 }
429 
put_cont_catch(char * put_str,char * arg)430 static int put_cont_catch(char *put_str, char *arg)
431 {
432 	/* This is at the end of the test and we catch any and all input */
433 	v2printk("kgdbts: cleanup task: %lx\n", sstep_thread_id);
434 	ts.idx--;
435 	return 0;
436 }
437 
emul_reset(char * put_str,char * arg)438 static int emul_reset(char *put_str, char *arg)
439 {
440 	if (strncmp(put_str, "$OK", 3))
441 		return 1;
442 	if (restart_from_top_after_write) {
443 		restart_from_top_after_write = 0;
444 		ts.idx = -1;
445 	}
446 	return 0;
447 }
448 
emul_sstep_get(char * arg)449 static void emul_sstep_get(char *arg)
450 {
451 	if (!arch_needs_sstep_emulation) {
452 		if (cont_instead_of_sstep) {
453 			cont_instead_of_sstep = 0;
454 			fill_get_buf("c");
455 		} else {
456 			fill_get_buf(arg);
457 		}
458 		return;
459 	}
460 	switch (sstep_state) {
461 	case 0:
462 		v2printk("Emulate single step\n");
463 		/* Start by looking at the current PC */
464 		fill_get_buf("g");
465 		break;
466 	case 1:
467 		/* set breakpoint */
468 		break_helper("Z0", NULL, sstep_addr);
469 		break;
470 	case 2:
471 		/* Continue */
472 		fill_get_buf("c");
473 		break;
474 	case 3:
475 		/* Clear breakpoint */
476 		break_helper("z0", NULL, sstep_addr);
477 		break;
478 	default:
479 		eprintk("kgdbts: ERROR failed sstep get emulation\n");
480 	}
481 	sstep_state++;
482 }
483 
emul_sstep_put(char * put_str,char * arg)484 static int emul_sstep_put(char *put_str, char *arg)
485 {
486 	if (!arch_needs_sstep_emulation) {
487 		char *ptr = &put_str[11];
488 		if (put_str[1] != 'T' || put_str[2] != '0')
489 			return 1;
490 		kgdb_hex2long(&ptr, &sstep_thread_id);
491 		return 0;
492 	}
493 	switch (sstep_state) {
494 	case 1:
495 		/* validate the "g" packet to get the IP */
496 		kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs,
497 			 NUMREGBYTES);
498 		gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
499 		v2printk("Stopped at IP: %lx\n",
500 			 instruction_pointer(&kgdbts_regs));
501 		/* Want to stop at IP + break instruction size by default */
502 		sstep_addr = cont_addr + BREAK_INSTR_SIZE;
503 		break;
504 	case 2:
505 		if (strncmp(put_str, "$OK", 3)) {
506 			eprintk("kgdbts: failed sstep break set\n");
507 			return 1;
508 		}
509 		break;
510 	case 3:
511 		if (strncmp(put_str, "$T0", 3)) {
512 			eprintk("kgdbts: failed continue sstep\n");
513 			return 1;
514 		} else {
515 			char *ptr = &put_str[11];
516 			kgdb_hex2long(&ptr, &sstep_thread_id);
517 		}
518 		break;
519 	case 4:
520 		if (strncmp(put_str, "$OK", 3)) {
521 			eprintk("kgdbts: failed sstep break unset\n");
522 			return 1;
523 		}
524 		/* Single step is complete so continue on! */
525 		sstep_state = 0;
526 		return 0;
527 	default:
528 		eprintk("kgdbts: ERROR failed sstep put emulation\n");
529 	}
530 
531 	/* Continue on the same test line until emulation is complete */
532 	ts.idx--;
533 	return 0;
534 }
535 
final_ack_set(char * put_str,char * arg)536 static int final_ack_set(char *put_str, char *arg)
537 {
538 	if (strncmp(put_str+1, arg, 2))
539 		return 1;
540 	final_ack = 1;
541 	return 0;
542 }
543 /*
544  * Test to plant a breakpoint and detach, which should clear out the
545  * breakpoint and restore the original instruction.
546  */
547 static struct test_struct plant_and_detach_test[] = {
548 	{ "?", "S0*" }, /* Clear break points */
549 	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
550 	{ "D", "OK" }, /* Detach */
551 	{ "", "" },
552 };
553 
554 /*
555  * Simple test to write in a software breakpoint, check for the
556  * correct stop location and detach.
557  */
558 static struct test_struct sw_breakpoint_test[] = {
559 	{ "?", "S0*" }, /* Clear break points */
560 	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
561 	{ "c", "T0*", }, /* Continue */
562 	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },
563 	{ "write", "OK", write_regs },
564 	{ "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
565 	{ "D", "OK" }, /* Detach */
566 	{ "D", "OK", NULL,  got_break }, /* On success we made it here */
567 	{ "", "" },
568 };
569 
570 /*
571  * Test a known bad memory read location to test the fault handler and
572  * read bytes 1-8 at the bad address
573  */
574 static struct test_struct bad_read_test[] = {
575 	{ "?", "S0*" }, /* Clear break points */
576 	{ "m0,1", "E*" }, /* read 1 byte at address 1 */
577 	{ "m0,2", "E*" }, /* read 1 byte at address 2 */
578 	{ "m0,3", "E*" }, /* read 1 byte at address 3 */
579 	{ "m0,4", "E*" }, /* read 1 byte at address 4 */
580 	{ "m0,5", "E*" }, /* read 1 byte at address 5 */
581 	{ "m0,6", "E*" }, /* read 1 byte at address 6 */
582 	{ "m0,7", "E*" }, /* read 1 byte at address 7 */
583 	{ "m0,8", "E*" }, /* read 1 byte at address 8 */
584 	{ "D", "OK" }, /* Detach which removes all breakpoints and continues */
585 	{ "", "" },
586 };
587 
588 /*
589  * Test for hitting a breakpoint, remove it, single step, plant it
590  * again and detach.
591  */
592 static struct test_struct singlestep_break_test[] = {
593 	{ "?", "S0*" }, /* Clear break points */
594 	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
595 	{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
596 	{ "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
597 	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },
598 	{ "write", "OK", write_regs }, /* Write registers */
599 	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
600 	{ "g", "kgdbts_break_test", NULL, check_single_step },
601 	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
602 	{ "c", "T0*", }, /* Continue */
603 	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },
604 	{ "write", "OK", write_regs }, /* Write registers */
605 	{ "D", "OK" }, /* Remove all breakpoints and continues */
606 	{ "", "" },
607 };
608 
609 /*
610  * Test for hitting a breakpoint at kernel_clone for what ever the number
611  * of iterations required by the variable repeat_test.
612  */
613 static struct test_struct do_kernel_clone_test[] = {
614 	{ "?", "S0*" }, /* Clear break points */
615 	{ "kernel_clone", "OK", sw_break, }, /* set sw breakpoint */
616 	{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
617 	{ "kernel_clone", "OK", sw_rem_break }, /*remove breakpoint */
618 	{ "g", "kernel_clone", NULL, check_and_rewind_pc }, /* check location */
619 	{ "write", "OK", write_regs, emul_reset }, /* Write registers */
620 	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
621 	{ "g", "kernel_clone", NULL, check_single_step },
622 	{ "kernel_clone", "OK", sw_break, }, /* set sw breakpoint */
623 	{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
624 	{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */
625 	{ "", "", get_cont_catch, put_cont_catch },
626 };
627 
628 /* Test for hitting a breakpoint at sys_open for what ever the number
629  * of iterations required by the variable repeat_test.
630  */
631 static struct test_struct sys_open_test[] = {
632 	{ "?", "S0*" }, /* Clear break points */
633 	{ "do_sys_openat2", "OK", sw_break, }, /* set sw breakpoint */
634 	{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
635 	{ "do_sys_openat2", "OK", sw_rem_break }, /*remove breakpoint */
636 	{ "g", "do_sys_openat2", NULL, check_and_rewind_pc }, /* check location */
637 	{ "write", "OK", write_regs, emul_reset }, /* Write registers */
638 	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
639 	{ "g", "do_sys_openat2", NULL, check_single_step },
640 	{ "do_sys_openat2", "OK", sw_break, }, /* set sw breakpoint */
641 	{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
642 	{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */
643 	{ "", "", get_cont_catch, put_cont_catch },
644 };
645 
646 /*
647  * Test for hitting a simple hw breakpoint
648  */
649 static struct test_struct hw_breakpoint_test[] = {
650 	{ "?", "S0*" }, /* Clear break points */
651 	{ "kgdbts_break_test", "OK", hw_break, }, /* set hw breakpoint */
652 	{ "c", "T0*", }, /* Continue */
653 	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },
654 	{ "write", "OK", write_regs },
655 	{ "kgdbts_break_test", "OK", hw_rem_break }, /*remove breakpoint */
656 	{ "D", "OK" }, /* Detach */
657 	{ "D", "OK", NULL,  got_break }, /* On success we made it here */
658 	{ "", "" },
659 };
660 
661 /*
662  * Test for hitting a hw write breakpoint
663  */
664 static struct test_struct hw_write_break_test[] = {
665 	{ "?", "S0*" }, /* Clear break points */
666 	{ "hw_break_val", "OK", hw_write_break, }, /* set hw breakpoint */
667 	{ "c", "T0*", NULL, got_break }, /* Continue */
668 	{ "g", "silent", NULL, check_and_rewind_pc },
669 	{ "write", "OK", write_regs },
670 	{ "hw_break_val", "OK", hw_rem_write_break }, /*remove breakpoint */
671 	{ "D", "OK" }, /* Detach */
672 	{ "D", "OK", NULL,  got_break }, /* On success we made it here */
673 	{ "", "" },
674 };
675 
676 /*
677  * Test for hitting a hw access breakpoint
678  */
679 static struct test_struct hw_access_break_test[] = {
680 	{ "?", "S0*" }, /* Clear break points */
681 	{ "hw_break_val", "OK", hw_access_break, }, /* set hw breakpoint */
682 	{ "c", "T0*", NULL, got_break }, /* Continue */
683 	{ "g", "silent", NULL, check_and_rewind_pc },
684 	{ "write", "OK", write_regs },
685 	{ "hw_break_val", "OK", hw_rem_access_break }, /*remove breakpoint */
686 	{ "D", "OK" }, /* Detach */
687 	{ "D", "OK", NULL,  got_break }, /* On success we made it here */
688 	{ "", "" },
689 };
690 
691 /*
692  * Test for hitting a hw access breakpoint
693  */
694 static struct test_struct nmi_sleep_test[] = {
695 	{ "?", "S0*" }, /* Clear break points */
696 	{ "c", "T0*", NULL, got_break }, /* Continue */
697 	{ "D", "OK" }, /* Detach */
698 	{ "D", "OK", NULL,  got_break }, /* On success we made it here */
699 	{ "", "" },
700 };
701 
fill_get_buf(char * buf)702 static void fill_get_buf(char *buf)
703 {
704 	unsigned char checksum = 0;
705 	int count = 0;
706 	char ch;
707 
708 	strcpy(get_buf, "$");
709 	strcat(get_buf, buf);
710 	while ((ch = buf[count])) {
711 		checksum += ch;
712 		count++;
713 	}
714 	strcat(get_buf, "#");
715 	get_buf[count + 2] = hex_asc_hi(checksum);
716 	get_buf[count + 3] = hex_asc_lo(checksum);
717 	get_buf[count + 4] = '\0';
718 	v2printk("get%i: %s\n", ts.idx, get_buf);
719 }
720 
validate_simple_test(char * put_str)721 static int validate_simple_test(char *put_str)
722 {
723 	char *chk_str;
724 
725 	if (ts.tst[ts.idx].put_handler)
726 		return ts.tst[ts.idx].put_handler(put_str,
727 			ts.tst[ts.idx].put);
728 
729 	chk_str = ts.tst[ts.idx].put;
730 	if (*put_str == '$')
731 		put_str++;
732 
733 	while (*chk_str != '\0' && *put_str != '\0') {
734 		/* If someone does a * to match the rest of the string, allow
735 		 * it, or stop if the received string is complete.
736 		 */
737 		if (*put_str == '#' || *chk_str == '*')
738 			return 0;
739 		if (*put_str != *chk_str)
740 			return 1;
741 
742 		chk_str++;
743 		put_str++;
744 	}
745 	if (*chk_str == '\0' && (*put_str == '\0' || *put_str == '#'))
746 		return 0;
747 
748 	return 1;
749 }
750 
run_simple_test(int is_get_char,int chr)751 static int run_simple_test(int is_get_char, int chr)
752 {
753 	int ret = 0;
754 	if (is_get_char) {
755 		/* Send an ACK on the get if a prior put completed and set the
756 		 * send ack variable
757 		 */
758 		if (send_ack) {
759 			send_ack = 0;
760 			return '+';
761 		}
762 		/* On the first get char, fill the transmit buffer and then
763 		 * take from the get_string.
764 		 */
765 		if (get_buf_cnt == 0) {
766 			if (ts.tst[ts.idx].get_handler)
767 				ts.tst[ts.idx].get_handler(ts.tst[ts.idx].get);
768 			else
769 				fill_get_buf(ts.tst[ts.idx].get);
770 		}
771 
772 		if (get_buf[get_buf_cnt] == '\0') {
773 			eprintk("kgdbts: ERROR GET: EOB on '%s' at %i\n",
774 			   ts.name, ts.idx);
775 			get_buf_cnt = 0;
776 			fill_get_buf("D");
777 		}
778 		ret = get_buf[get_buf_cnt];
779 		get_buf_cnt++;
780 		return ret;
781 	}
782 
783 	/* This callback is a put char which is when kgdb sends data to
784 	 * this I/O module.
785 	 */
786 	if (ts.tst[ts.idx].get[0] == '\0' && ts.tst[ts.idx].put[0] == '\0' &&
787 	    !ts.tst[ts.idx].get_handler) {
788 		eprintk("kgdbts: ERROR: beyond end of test on"
789 			   " '%s' line %i\n", ts.name, ts.idx);
790 		return 0;
791 	}
792 
793 	if (put_buf_cnt >= BUFMAX) {
794 		eprintk("kgdbts: ERROR: put buffer overflow on"
795 			   " '%s' line %i\n", ts.name, ts.idx);
796 		put_buf_cnt = 0;
797 		return 0;
798 	}
799 	/* Ignore everything until the first valid packet start '$' */
800 	if (put_buf_cnt == 0 && chr != '$')
801 		return 0;
802 
803 	put_buf[put_buf_cnt] = chr;
804 	put_buf_cnt++;
805 
806 	/* End of packet == #XX so look for the '#' */
807 	if (put_buf_cnt > 3 && put_buf[put_buf_cnt - 3] == '#') {
808 		if (put_buf_cnt >= BUFMAX) {
809 			eprintk("kgdbts: ERROR: put buffer overflow on"
810 				" '%s' line %i\n", ts.name, ts.idx);
811 			put_buf_cnt = 0;
812 			return 0;
813 		}
814 		put_buf[put_buf_cnt] = '\0';
815 		v2printk("put%i: %s\n", ts.idx, put_buf);
816 		/* Trigger check here */
817 		if (ts.validate_put && ts.validate_put(put_buf)) {
818 			eprintk("kgdbts: ERROR PUT: end of test "
819 			   "buffer on '%s' line %i expected %s got %s\n",
820 			   ts.name, ts.idx, ts.tst[ts.idx].put, put_buf);
821 		}
822 		ts.idx++;
823 		put_buf_cnt = 0;
824 		get_buf_cnt = 0;
825 		send_ack = 1;
826 	}
827 	return 0;
828 }
829 
init_simple_test(void)830 static void init_simple_test(void)
831 {
832 	memset(&ts, 0, sizeof(ts));
833 	ts.run_test = run_simple_test;
834 	ts.validate_put = validate_simple_test;
835 }
836 
run_plant_and_detach_test(int is_early)837 static void run_plant_and_detach_test(int is_early)
838 {
839 	char before[BREAK_INSTR_SIZE];
840 	char after[BREAK_INSTR_SIZE];
841 
842 	copy_from_kernel_nofault(before, (char *)kgdbts_break_test,
843 	  BREAK_INSTR_SIZE);
844 	init_simple_test();
845 	ts.tst = plant_and_detach_test;
846 	ts.name = "plant_and_detach_test";
847 	/* Activate test with initial breakpoint */
848 	if (!is_early)
849 		kgdb_breakpoint();
850 	copy_from_kernel_nofault(after, (char *)kgdbts_break_test,
851 			BREAK_INSTR_SIZE);
852 	if (memcmp(before, after, BREAK_INSTR_SIZE)) {
853 		printk(KERN_CRIT "kgdbts: ERROR kgdb corrupted memory\n");
854 		panic("kgdb memory corruption");
855 	}
856 
857 	/* complete the detach test */
858 	if (!is_early)
859 		kgdbts_break_test();
860 }
861 
run_breakpoint_test(int is_hw_breakpoint)862 static void run_breakpoint_test(int is_hw_breakpoint)
863 {
864 	test_complete = 0;
865 	init_simple_test();
866 	if (is_hw_breakpoint) {
867 		ts.tst = hw_breakpoint_test;
868 		ts.name = "hw_breakpoint_test";
869 	} else {
870 		ts.tst = sw_breakpoint_test;
871 		ts.name = "sw_breakpoint_test";
872 	}
873 	/* Activate test with initial breakpoint */
874 	kgdb_breakpoint();
875 	/* run code with the break point in it */
876 	kgdbts_break_test();
877 	kgdb_breakpoint();
878 
879 	if (test_complete)
880 		return;
881 
882 	eprintk("kgdbts: ERROR %s test failed\n", ts.name);
883 	if (is_hw_breakpoint)
884 		hwbreaks_ok = 0;
885 }
886 
run_hw_break_test(int is_write_test)887 static void run_hw_break_test(int is_write_test)
888 {
889 	test_complete = 0;
890 	init_simple_test();
891 	if (is_write_test) {
892 		ts.tst = hw_write_break_test;
893 		ts.name = "hw_write_break_test";
894 	} else {
895 		ts.tst = hw_access_break_test;
896 		ts.name = "hw_access_break_test";
897 	}
898 	/* Activate test with initial breakpoint */
899 	kgdb_breakpoint();
900 	hw_break_val_access();
901 	if (is_write_test) {
902 		if (test_complete == 2) {
903 			eprintk("kgdbts: ERROR %s broke on access\n",
904 				ts.name);
905 			hwbreaks_ok = 0;
906 		}
907 		hw_break_val_write();
908 	}
909 	kgdb_breakpoint();
910 
911 	if (test_complete == 1)
912 		return;
913 
914 	eprintk("kgdbts: ERROR %s test failed\n", ts.name);
915 	hwbreaks_ok = 0;
916 }
917 
run_nmi_sleep_test(int nmi_sleep)918 static void run_nmi_sleep_test(int nmi_sleep)
919 {
920 	unsigned long flags;
921 
922 	init_simple_test();
923 	ts.tst = nmi_sleep_test;
924 	ts.name = "nmi_sleep_test";
925 	/* Activate test with initial breakpoint */
926 	kgdb_breakpoint();
927 	local_irq_save(flags);
928 	mdelay(nmi_sleep*1000);
929 	touch_nmi_watchdog();
930 	local_irq_restore(flags);
931 	if (test_complete != 2)
932 		eprintk("kgdbts: ERROR nmi_test did not hit nmi\n");
933 	kgdb_breakpoint();
934 	if (test_complete == 1)
935 		return;
936 
937 	eprintk("kgdbts: ERROR %s test failed\n", ts.name);
938 }
939 
run_bad_read_test(void)940 static void run_bad_read_test(void)
941 {
942 	init_simple_test();
943 	ts.tst = bad_read_test;
944 	ts.name = "bad_read_test";
945 	/* Activate test with initial breakpoint */
946 	kgdb_breakpoint();
947 }
948 
run_kernel_clone_test(void)949 static void run_kernel_clone_test(void)
950 {
951 	init_simple_test();
952 	ts.tst = do_kernel_clone_test;
953 	ts.name = "do_kernel_clone_test";
954 	/* Activate test with initial breakpoint */
955 	kgdb_breakpoint();
956 }
957 
run_sys_open_test(void)958 static void run_sys_open_test(void)
959 {
960 	init_simple_test();
961 	ts.tst = sys_open_test;
962 	ts.name = "sys_open_test";
963 	/* Activate test with initial breakpoint */
964 	kgdb_breakpoint();
965 }
966 
run_singlestep_break_test(void)967 static void run_singlestep_break_test(void)
968 {
969 	init_simple_test();
970 	ts.tst = singlestep_break_test;
971 	ts.name = "singlestep_breakpoint_test";
972 	/* Activate test with initial breakpoint */
973 	kgdb_breakpoint();
974 	kgdbts_break_test();
975 	kgdbts_break_test();
976 }
977 
kgdbts_run_tests(void)978 static void kgdbts_run_tests(void)
979 {
980 	char *ptr;
981 	int clone_test = 0;
982 	int do_sys_open_test = 0;
983 	int sstep_test = 1000;
984 	int nmi_sleep = 0;
985 	int i;
986 
987 	verbose = 0;
988 	if (strstr(config, "V1"))
989 		verbose = 1;
990 	if (strstr(config, "V2"))
991 		verbose = 2;
992 
993 	ptr = strchr(config, 'F');
994 	if (ptr)
995 		clone_test = simple_strtol(ptr + 1, NULL, 10);
996 	ptr = strchr(config, 'S');
997 	if (ptr)
998 		do_sys_open_test = simple_strtol(ptr + 1, NULL, 10);
999 	ptr = strchr(config, 'N');
1000 	if (ptr)
1001 		nmi_sleep = simple_strtol(ptr+1, NULL, 10);
1002 	ptr = strchr(config, 'I');
1003 	if (ptr)
1004 		sstep_test = simple_strtol(ptr+1, NULL, 10);
1005 
1006 	/* All HW break point tests */
1007 	if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) {
1008 		hwbreaks_ok = 1;
1009 		v1printk("kgdbts:RUN hw breakpoint test\n");
1010 		run_breakpoint_test(1);
1011 		v1printk("kgdbts:RUN hw write breakpoint test\n");
1012 		run_hw_break_test(1);
1013 		v1printk("kgdbts:RUN access write breakpoint test\n");
1014 		run_hw_break_test(0);
1015 	}
1016 
1017 	/* required internal KGDB tests */
1018 	v1printk("kgdbts:RUN plant and detach test\n");
1019 	run_plant_and_detach_test(0);
1020 	v1printk("kgdbts:RUN sw breakpoint test\n");
1021 	run_breakpoint_test(0);
1022 	v1printk("kgdbts:RUN bad memory access test\n");
1023 	run_bad_read_test();
1024 	v1printk("kgdbts:RUN singlestep test %i iterations\n", sstep_test);
1025 	for (i = 0; i < sstep_test; i++) {
1026 		run_singlestep_break_test();
1027 		if (i % 100 == 0)
1028 			v1printk("kgdbts:RUN singlestep [%i/%i]\n",
1029 				 i, sstep_test);
1030 	}
1031 
1032 	/* ===Optional tests=== */
1033 
1034 	if (nmi_sleep) {
1035 		v1printk("kgdbts:RUN NMI sleep %i seconds test\n", nmi_sleep);
1036 		run_nmi_sleep_test(nmi_sleep);
1037 	}
1038 
1039 	/* If the kernel_clone test is run it will be the last test that is
1040 	 * executed because a kernel thread will be spawned at the very
1041 	 * end to unregister the debug hooks.
1042 	 */
1043 	if (clone_test) {
1044 		repeat_test = clone_test;
1045 		printk(KERN_INFO "kgdbts:RUN kernel_clone for %i breakpoints\n",
1046 			repeat_test);
1047 		kthread_run(kgdbts_unreg_thread, NULL, "kgdbts_unreg");
1048 		run_kernel_clone_test();
1049 		return;
1050 	}
1051 
1052 	/* If the sys_open test is run it will be the last test that is
1053 	 * executed because a kernel thread will be spawned at the very
1054 	 * end to unregister the debug hooks.
1055 	 */
1056 	if (do_sys_open_test) {
1057 		repeat_test = do_sys_open_test;
1058 		printk(KERN_INFO "kgdbts:RUN sys_open for %i breakpoints\n",
1059 			repeat_test);
1060 		kthread_run(kgdbts_unreg_thread, NULL, "kgdbts_unreg");
1061 		run_sys_open_test();
1062 		return;
1063 	}
1064 	/* Shutdown and unregister */
1065 	kgdb_unregister_io_module(&kgdbts_io_ops);
1066 	configured = 0;
1067 }
1068 
kgdbts_option_setup(char * opt)1069 static int kgdbts_option_setup(char *opt)
1070 {
1071 	if (strlen(opt) >= MAX_CONFIG_LEN) {
1072 		printk(KERN_ERR "kgdbts: config string too long\n");
1073 		return 1;
1074 	}
1075 	strcpy(config, opt);
1076 	return 1;
1077 }
1078 
1079 __setup("kgdbts=", kgdbts_option_setup);
1080 
configure_kgdbts(void)1081 static int configure_kgdbts(void)
1082 {
1083 	int err = 0;
1084 
1085 	if (!strlen(config) || isspace(config[0]))
1086 		goto noconfig;
1087 
1088 	final_ack = 0;
1089 	run_plant_and_detach_test(1);
1090 
1091 	err = kgdb_register_io_module(&kgdbts_io_ops);
1092 	if (err) {
1093 		configured = 0;
1094 		return err;
1095 	}
1096 	configured = 1;
1097 	kgdbts_run_tests();
1098 
1099 	return err;
1100 
1101 noconfig:
1102 	config[0] = 0;
1103 	configured = 0;
1104 
1105 	return err;
1106 }
1107 
init_kgdbts(void)1108 static int __init init_kgdbts(void)
1109 {
1110 	/* Already configured? */
1111 	if (configured == 1)
1112 		return 0;
1113 
1114 	return configure_kgdbts();
1115 }
1116 device_initcall(init_kgdbts);
1117 
kgdbts_get_char(void)1118 static int kgdbts_get_char(void)
1119 {
1120 	int val = 0;
1121 
1122 	if (ts.run_test)
1123 		val = ts.run_test(1, 0);
1124 
1125 	return val;
1126 }
1127 
kgdbts_put_char(u8 chr)1128 static void kgdbts_put_char(u8 chr)
1129 {
1130 	if (ts.run_test)
1131 		ts.run_test(0, chr);
1132 }
1133 
param_set_kgdbts_var(const char * kmessage,const struct kernel_param * kp)1134 static int param_set_kgdbts_var(const char *kmessage,
1135 				const struct kernel_param *kp)
1136 {
1137 	size_t len = strlen(kmessage);
1138 
1139 	if (len >= MAX_CONFIG_LEN) {
1140 		printk(KERN_ERR "kgdbts: config string too long\n");
1141 		return -ENOSPC;
1142 	}
1143 
1144 	/* Only copy in the string if the init function has not run yet */
1145 	if (configured < 0) {
1146 		strcpy(config, kmessage);
1147 		return 0;
1148 	}
1149 
1150 	if (configured == 1) {
1151 		printk(KERN_ERR "kgdbts: ERROR: Already configured and running.\n");
1152 		return -EBUSY;
1153 	}
1154 
1155 	strcpy(config, kmessage);
1156 	/* Chop out \n char as a result of echo */
1157 	if (len && config[len - 1] == '\n')
1158 		config[len - 1] = '\0';
1159 
1160 	/* Go and configure with the new params. */
1161 	return configure_kgdbts();
1162 }
1163 
kgdbts_pre_exp_handler(void)1164 static void kgdbts_pre_exp_handler(void)
1165 {
1166 	/* Increment the module count when the debugger is active */
1167 	if (!kgdb_connected)
1168 		try_module_get(THIS_MODULE);
1169 }
1170 
kgdbts_post_exp_handler(void)1171 static void kgdbts_post_exp_handler(void)
1172 {
1173 	/* decrement the module count when the debugger detaches */
1174 	if (!kgdb_connected)
1175 		module_put(THIS_MODULE);
1176 }
1177 
1178 static struct kgdb_io kgdbts_io_ops = {
1179 	.name			= "kgdbts",
1180 	.read_char		= kgdbts_get_char,
1181 	.write_char		= kgdbts_put_char,
1182 	.pre_exception		= kgdbts_pre_exp_handler,
1183 	.post_exception		= kgdbts_post_exp_handler,
1184 };
1185 
1186 /*
1187  * not really modular, but the easiest way to keep compat with existing
1188  * bootargs behaviour is to continue using module_param here.
1189  */
1190 module_param_call(kgdbts, param_set_kgdbts_var, param_get_string, &kps, 0644);
1191 MODULE_PARM_DESC(kgdbts, "<A|V1|V2>[F#|S#][N#]");
1192