// SPDX-License-Identifier: GPL-2.0-only

  /*
   * kgdbts is a test suite for kgdb for the sole purpose of validating
   * that key pieces of the kgdb internals are working properly such as
   * HW/SW breakpoints, single stepping, and NMI.
   *
   * Created by: Jason Wessel <jason.wessel@windriver.com>
   *
   * Copyright (c) 2008 Wind River Systems, Inc.

   */
  /* Information about the kgdb test suite.
   * -------------------------------------
   *
   * The kgdb test suite is designed as a KGDB I/O module which
   * simulates the communications that a debugger would have with kgdb.
   * The tests are broken up in to a line by line and referenced here as
   * a "get" which is kgdb requesting input and "put" which is kgdb
   * sending a response.
   *
   * The kgdb suite can be invoked from the kernel command line
   * arguments system or executed dynamically at run time.  The test
   * suite uses the variable "kgdbts" to obtain the information about
   * which tests to run and to configure the verbosity level.  The
   * following are the various characters you can use with the kgdbts=
   * line:
   *
   * When using the "kgdbts=" you only choose one of the following core
   * test types:
   * A = Run all the core tests silently
   * V1 = Run all the core tests with minimal output
   * V2 = Run all the core tests in debug mode
   *
   * You can also specify optional tests:
   * N## = Go to sleep with interrupts of for ## seconds
   *       to test the HW NMI watchdog
   * F## = Break at do_fork for ## iterations
   * S## = Break at sys_open for ## iterations

   * I## = Run the single step test ## iterations

   *
   * NOTE: that the do_fork and sys_open tests are mutually exclusive.
   *
   * To invoke the kgdb test suite from boot you use a kernel start
   * argument as follows:
   * 	kgdbts=V1 kgdbwait
   * Or if you wanted to perform the NMI test for 6 seconds and do_fork
   * test for 100 forks, you could use:
   * 	kgdbts=V1N6F100 kgdbwait
   *
   * The test suite can also be invoked at run time with:
   *	echo kgdbts=V1N6F100 > /sys/module/kgdbts/parameters/kgdbts
   * Or as another example:
   *	echo kgdbts=V2 > /sys/module/kgdbts/parameters/kgdbts
   *
   * When developing a new kgdb arch specific implementation or
   * using these tests for the purpose of regression testing,
   * several invocations are required.
   *
   * 1) Boot with the test suite enabled by using the kernel arguments
   *       "kgdbts=V1F100 kgdbwait"
   *    ## If kgdb arch specific implementation has NMI use
   *       "kgdbts=V1N6F100
   *
   * 2) After the system boot run the basic test.
   * echo kgdbts=V1 > /sys/module/kgdbts/parameters/kgdbts
   *
   * 3) Run the concurrency tests.  It is best to use n+1
   *    while loops where n is the number of cpus you have
   *    in your system.  The example below uses only two
   *    loops.
   *
   * ## This tests break points on sys_open
   * while [ 1 ] ; do find / > /dev/null 2>&1 ; done &
   * while [ 1 ] ; do find / > /dev/null 2>&1 ; done &
   * echo kgdbts=V1S10000 > /sys/module/kgdbts/parameters/kgdbts
   * fg # and hit control-c
   * fg # and hit control-c
   * ## This tests break points on do_fork
   * while [ 1 ] ; do date > /dev/null ; done &
   * while [ 1 ] ; do date > /dev/null ; done &
   * echo kgdbts=V1F1000 > /sys/module/kgdbts/parameters/kgdbts
   * fg # and hit control-c
   *
   */
  
  #include <linux/kernel.h>
  #include <linux/kgdb.h>
  #include <linux/ctype.h>
  #include <linux/uaccess.h>
  #include <linux/syscalls.h>
  #include <linux/nmi.h>
  #include <linux/delay.h>
  #include <linux/kthread.h>

  #include <linux/module.h>

  #include <linux/sched/task.h>

  #include <asm/sections.h>

  
  #define v1printk(a...) do { \
  	if (verbose) \
  		printk(KERN_INFO a); \
  	} while (0)
  #define v2printk(a...) do { \
  	if (verbose > 1) \
  		printk(KERN_INFO a); \
  		touch_nmi_watchdog();	\
  	} while (0)

  #define eprintk(a...) do { \
  		printk(KERN_ERR a); \
  		WARN_ON(1); \
  	} while (0)

  #define MAX_CONFIG_LEN		40

  static struct kgdb_io kgdbts_io_ops;
  static char get_buf[BUFMAX];
  static int get_buf_cnt;
  static char put_buf[BUFMAX];
  static int put_buf_cnt;
  static char scratch_buf[BUFMAX];
  static int verbose;
  static int repeat_test;
  static int test_complete;
  static int send_ack;
  static int final_ack;

  static int force_hwbrks;
  static int hwbreaks_ok;

  static int hw_break_val;
  static int hw_break_val2;

  static int cont_instead_of_sstep;
  static unsigned long cont_thread_id;
  static unsigned long sstep_thread_id;

  #if defined(CONFIG_ARM) || defined(CONFIG_MIPS) || defined(CONFIG_SPARC)

  static int arch_needs_sstep_emulation = 1;
  #else
  static int arch_needs_sstep_emulation;
  #endif

  static unsigned long cont_addr;

  static unsigned long sstep_addr;

  static int restart_from_top_after_write;

  static int sstep_state;
  
  /* Storage for the registers, in GDB format. */
  static unsigned long kgdbts_gdb_regs[(NUMREGBYTES +
  					sizeof(unsigned long) - 1) /
  					sizeof(unsigned long)];
  static struct pt_regs kgdbts_regs;
  
  /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
  static int configured		= -1;

  #ifdef CONFIG_KGDB_TESTS_BOOT_STRING
  static char config[MAX_CONFIG_LEN] = CONFIG_KGDB_TESTS_BOOT_STRING;
  #else

  static char config[MAX_CONFIG_LEN];

  #endif

  static struct kparam_string kps = {
  	.string			= config,
  	.maxlen			= MAX_CONFIG_LEN,
  };
  
  static void fill_get_buf(char *buf);
  
  struct test_struct {
  	char *get;
  	char *put;
  	void (*get_handler)(char *);
  	int (*put_handler)(char *, char *);
  };
  
  struct test_state {
  	char *name;
  	struct test_struct *tst;
  	int idx;
  	int (*run_test) (int, int);
  	int (*validate_put) (char *);
  };
  
  static struct test_state ts;
  
  static int kgdbts_unreg_thread(void *ptr)
  {
  	/* Wait until the tests are complete and then ungresiter the I/O
  	 * driver.
  	 */
  	while (!final_ack)
  		msleep_interruptible(1500);

  	/* Pause for any other threads to exit after final ack. */
  	msleep_interruptible(1000);

  	if (configured)
  		kgdb_unregister_io_module(&kgdbts_io_ops);
  	configured = 0;
  
  	return 0;
  }
  
  /* This is noinline such that it can be used for a single location to
   * place a breakpoint
   */
  static noinline void kgdbts_break_test(void)
  {
  	v2printk("kgdbts: breakpoint complete
  ");
  }
  
  /* Lookup symbol info in the kernel */
  static unsigned long lookup_addr(char *arg)
  {
  	unsigned long addr = 0;
  
  	if (!strcmp(arg, "kgdbts_break_test"))
  		addr = (unsigned long)kgdbts_break_test;
  	else if (!strcmp(arg, "sys_open"))

  		addr = (unsigned long)do_sys_open;

  	else if (!strcmp(arg, "do_fork"))

  		addr = (unsigned long)_do_fork;

  	else if (!strcmp(arg, "hw_break_val"))
  		addr = (unsigned long)&hw_break_val;

  	addr = (unsigned long) dereference_function_descriptor((void *)addr);

  	return addr;
  }
  
  static void break_helper(char *bp_type, char *arg, unsigned long vaddr)
  {
  	unsigned long addr;
  
  	if (arg)
  		addr = lookup_addr(arg);
  	else
  		addr = vaddr;
  
  	sprintf(scratch_buf, "%s,%lx,%i", bp_type, addr,
  		BREAK_INSTR_SIZE);
  	fill_get_buf(scratch_buf);
  }
  
  static void sw_break(char *arg)
  {

  	break_helper(force_hwbrks ? "Z1" : "Z0", arg, 0);

  }
  
  static void sw_rem_break(char *arg)
  {

  	break_helper(force_hwbrks ? "z1" : "z0", arg, 0);

  }
  
  static void hw_break(char *arg)
  {
  	break_helper("Z1", arg, 0);
  }
  
  static void hw_rem_break(char *arg)
  {
  	break_helper("z1", arg, 0);
  }
  
  static void hw_write_break(char *arg)
  {
  	break_helper("Z2", arg, 0);
  }
  
  static void hw_rem_write_break(char *arg)
  {
  	break_helper("z2", arg, 0);
  }
  
  static void hw_access_break(char *arg)
  {
  	break_helper("Z4", arg, 0);
  }
  
  static void hw_rem_access_break(char *arg)
  {
  	break_helper("z4", arg, 0);
  }
  
  static void hw_break_val_access(void)
  {
  	hw_break_val2 = hw_break_val;
  }
  
  static void hw_break_val_write(void)
  {
  	hw_break_val++;
  }

  static int get_thread_id_continue(char *put_str, char *arg)
  {
  	char *ptr = &put_str[11];
  
  	if (put_str[1] != 'T' || put_str[2] != '0')
  		return 1;
  	kgdb_hex2long(&ptr, &cont_thread_id);
  	return 0;
  }

  static int check_and_rewind_pc(char *put_str, char *arg)
  {
  	unsigned long addr = lookup_addr(arg);

  	unsigned long ip;

  	int offset = 0;
  
  	kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs,
  		 NUMREGBYTES);
  	gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);

  	ip = instruction_pointer(&kgdbts_regs);
  	v2printk("Stopped at IP: %lx
  ", ip);
  #ifdef GDB_ADJUSTS_BREAK_OFFSET
  	/* On some arches, a breakpoint stop requires it to be decremented */
  	if (addr + BREAK_INSTR_SIZE == ip)
  		offset = -BREAK_INSTR_SIZE;

  #endif

  
  	if (arch_needs_sstep_emulation && sstep_addr &&
  	    ip + offset == sstep_addr &&
  	    ((!strcmp(arg, "sys_open") || !strcmp(arg, "do_fork")))) {
  		/* This is special case for emulated single step */
  		v2printk("Emul: rewind hit single step bp
  ");
  		restart_from_top_after_write = 1;
  	} else if (strcmp(arg, "silent") && ip + offset != addr) {

  		eprintk("kgdbts: BP mismatch %lx expected %lx
  ",

  			   ip + offset, addr);

  		return 1;
  	}

  	/* Readjust the instruction pointer if needed */

  	ip += offset;

  	cont_addr = ip;

  #ifdef GDB_ADJUSTS_BREAK_OFFSET
  	instruction_pointer_set(&kgdbts_regs, ip);
  #endif

  	return 0;
  }
  
  static int check_single_step(char *put_str, char *arg)
  {
  	unsigned long addr = lookup_addr(arg);

  	static int matched_id;

  	/*
  	 * From an arch indepent point of view the instruction pointer
  	 * should be on a different instruction
  	 */
  	kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs,
  		 NUMREGBYTES);
  	gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
  	v2printk("Singlestep stopped at IP: %lx
  ",
  		   instruction_pointer(&kgdbts_regs));

  	if (sstep_thread_id != cont_thread_id) {

  		/*
  		 * Ensure we stopped in the same thread id as before, else the
  		 * debugger should continue until the original thread that was
  		 * single stepped is scheduled again, emulating gdb's behavior.
  		 */
  		v2printk("ThrID does not match: %lx
  ", cont_thread_id);

  		if (arch_needs_sstep_emulation) {
  			if (matched_id &&
  			    instruction_pointer(&kgdbts_regs) != addr)
  				goto continue_test;
  			matched_id++;
  			ts.idx -= 2;
  			sstep_state = 0;
  			return 0;
  		}

  		cont_instead_of_sstep = 1;
  		ts.idx -= 4;
  		return 0;
  	}

  continue_test:
  	matched_id = 0;

  	if (instruction_pointer(&kgdbts_regs) == addr) {

  		eprintk("kgdbts: SingleStep failed at %lx
  ",

  			   instruction_pointer(&kgdbts_regs));
  		return 1;
  	}
  
  	return 0;
  }
  
  static void write_regs(char *arg)
  {
  	memset(scratch_buf, 0, sizeof(scratch_buf));
  	scratch_buf[0] = 'G';
  	pt_regs_to_gdb_regs(kgdbts_gdb_regs, &kgdbts_regs);
  	kgdb_mem2hex((char *)kgdbts_gdb_regs, &scratch_buf[1], NUMREGBYTES);
  	fill_get_buf(scratch_buf);
  }
  
  static void skip_back_repeat_test(char *arg)
  {
  	int go_back = simple_strtol(arg, NULL, 10);
  
  	repeat_test--;

  	if (repeat_test <= 0) {

  		ts.idx++;

  	} else {
  		if (repeat_test % 100 == 0)
  			v1printk("kgdbts:RUN ... %d remaining
  ", repeat_test);

  		ts.idx -= go_back;

  	}

  	fill_get_buf(ts.tst[ts.idx].get);
  }
  
  static int got_break(char *put_str, char *arg)
  {
  	test_complete = 1;
  	if (!strncmp(put_str+1, arg, 2)) {
  		if (!strncmp(arg, "T0", 2))
  			test_complete = 2;
  		return 0;
  	}
  	return 1;
  }

  static void get_cont_catch(char *arg)
  {
  	/* Always send detach because the test is completed at this point */
  	fill_get_buf("D");
  }
  
  static int put_cont_catch(char *put_str, char *arg)
  {
  	/* This is at the end of the test and we catch any and all input */
  	v2printk("kgdbts: cleanup task: %lx
  ", sstep_thread_id);
  	ts.idx--;
  	return 0;
  }
  
  static int emul_reset(char *put_str, char *arg)
  {
  	if (strncmp(put_str, "$OK", 3))
  		return 1;
  	if (restart_from_top_after_write) {
  		restart_from_top_after_write = 0;
  		ts.idx = -1;
  	}
  	return 0;
  }

  static void emul_sstep_get(char *arg)
  {
  	if (!arch_needs_sstep_emulation) {

  		if (cont_instead_of_sstep) {
  			cont_instead_of_sstep = 0;
  			fill_get_buf("c");
  		} else {
  			fill_get_buf(arg);
  		}

  		return;
  	}
  	switch (sstep_state) {
  	case 0:
  		v2printk("Emulate single step
  ");
  		/* Start by looking at the current PC */
  		fill_get_buf("g");
  		break;
  	case 1:
  		/* set breakpoint */

  		break_helper("Z0", NULL, sstep_addr);

  		break;
  	case 2:
  		/* Continue */
  		fill_get_buf("c");
  		break;
  	case 3:
  		/* Clear breakpoint */

  		break_helper("z0", NULL, sstep_addr);

  		break;
  	default:

  		eprintk("kgdbts: ERROR failed sstep get emulation
  ");

  	}
  	sstep_state++;
  }
  
  static int emul_sstep_put(char *put_str, char *arg)
  {
  	if (!arch_needs_sstep_emulation) {

  		char *ptr = &put_str[11];
  		if (put_str[1] != 'T' || put_str[2] != '0')
  			return 1;
  		kgdb_hex2long(&ptr, &sstep_thread_id);
  		return 0;

  	}
  	switch (sstep_state) {
  	case 1:
  		/* validate the "g" packet to get the IP */
  		kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs,
  			 NUMREGBYTES);
  		gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
  		v2printk("Stopped at IP: %lx
  ",
  			 instruction_pointer(&kgdbts_regs));
  		/* Want to stop at IP + break instruction size by default */

  		sstep_addr = cont_addr + BREAK_INSTR_SIZE;

  		break;
  	case 2:
  		if (strncmp(put_str, "$OK", 3)) {

  			eprintk("kgdbts: failed sstep break set
  ");

  			return 1;
  		}
  		break;
  	case 3:
  		if (strncmp(put_str, "$T0", 3)) {

  			eprintk("kgdbts: failed continue sstep
  ");

  			return 1;

  		} else {
  			char *ptr = &put_str[11];
  			kgdb_hex2long(&ptr, &sstep_thread_id);

  		}
  		break;
  	case 4:
  		if (strncmp(put_str, "$OK", 3)) {

  			eprintk("kgdbts: failed sstep break unset
  ");

  			return 1;
  		}
  		/* Single step is complete so continue on! */
  		sstep_state = 0;
  		return 0;
  	default:

  		eprintk("kgdbts: ERROR failed sstep put emulation
  ");

  	}
  
  	/* Continue on the same test line until emulation is complete */
  	ts.idx--;
  	return 0;
  }
  
  static int final_ack_set(char *put_str, char *arg)
  {
  	if (strncmp(put_str+1, arg, 2))
  		return 1;
  	final_ack = 1;
  	return 0;
  }
  /*
   * Test to plant a breakpoint and detach, which should clear out the
   * breakpoint and restore the original instruction.
   */
  static struct test_struct plant_and_detach_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
  	{ "D", "OK" }, /* Detach */
  	{ "", "" },
  };
  
  /*
   * Simple test to write in a software breakpoint, check for the
   * correct stop location and detach.
   */
  static struct test_struct sw_breakpoint_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
  	{ "c", "T0*", }, /* Continue */

  	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },

  	{ "write", "OK", write_regs },
  	{ "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
  	{ "D", "OK" }, /* Detach */

  	{ "D", "OK", NULL,  got_break }, /* On success we made it here */

  	{ "", "" },
  };
  
  /*
   * Test a known bad memory read location to test the fault handler and
   * read bytes 1-8 at the bad address
   */
  static struct test_struct bad_read_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "m0,1", "E*" }, /* read 1 byte at address 1 */
  	{ "m0,2", "E*" }, /* read 1 byte at address 2 */
  	{ "m0,3", "E*" }, /* read 1 byte at address 3 */
  	{ "m0,4", "E*" }, /* read 1 byte at address 4 */
  	{ "m0,5", "E*" }, /* read 1 byte at address 5 */
  	{ "m0,6", "E*" }, /* read 1 byte at address 6 */
  	{ "m0,7", "E*" }, /* read 1 byte at address 7 */
  	{ "m0,8", "E*" }, /* read 1 byte at address 8 */
  	{ "D", "OK" }, /* Detach which removes all breakpoints and continues */
  	{ "", "" },
  };
  
  /*
   * Test for hitting a breakpoint, remove it, single step, plant it
   * again and detach.
   */
  static struct test_struct singlestep_break_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */

  	{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
  	{ "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */

  	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },

  	{ "write", "OK", write_regs }, /* Write registers */

  	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */

  	{ "g", "kgdbts_break_test", NULL, check_single_step },

  	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
  	{ "c", "T0*", }, /* Continue */

  	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },

  	{ "write", "OK", write_regs }, /* Write registers */
  	{ "D", "OK" }, /* Remove all breakpoints and continues */
  	{ "", "" },
  };
  
  /*
   * Test for hitting a breakpoint at do_fork for what ever the number
   * of iterations required by the variable repeat_test.
   */
  static struct test_struct do_fork_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "do_fork", "OK", sw_break, }, /* set sw breakpoint */

  	{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
  	{ "do_fork", "OK", sw_rem_break }, /*remove breakpoint */

  	{ "g", "do_fork", NULL, check_and_rewind_pc }, /* check location */

  	{ "write", "OK", write_regs, emul_reset }, /* Write registers */

  	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */

  	{ "g", "do_fork", NULL, check_single_step },

  	{ "do_fork", "OK", sw_break, }, /* set sw breakpoint */
  	{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */

  	{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */

  	{ "", "", get_cont_catch, put_cont_catch },

  };
  
  /* Test for hitting a breakpoint at sys_open for what ever the number
   * of iterations required by the variable repeat_test.
   */
  static struct test_struct sys_open_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */

  	{ "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
  	{ "sys_open", "OK", sw_rem_break }, /*remove breakpoint */

  	{ "g", "sys_open", NULL, check_and_rewind_pc }, /* check location */

  	{ "write", "OK", write_regs, emul_reset }, /* Write registers */

  	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */

  	{ "g", "sys_open", NULL, check_single_step },

  	{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */
  	{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */

  	{ "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */

  	{ "", "", get_cont_catch, put_cont_catch },

  };
  
  /*
   * Test for hitting a simple hw breakpoint
   */
  static struct test_struct hw_breakpoint_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "kgdbts_break_test", "OK", hw_break, }, /* set hw breakpoint */
  	{ "c", "T0*", }, /* Continue */

  	{ "g", "kgdbts_break_test", NULL, check_and_rewind_pc },

  	{ "write", "OK", write_regs },
  	{ "kgdbts_break_test", "OK", hw_rem_break }, /*remove breakpoint */
  	{ "D", "OK" }, /* Detach */

  	{ "D", "OK", NULL,  got_break }, /* On success we made it here */

  	{ "", "" },
  };
  
  /*
   * Test for hitting a hw write breakpoint
   */
  static struct test_struct hw_write_break_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "hw_break_val", "OK", hw_write_break, }, /* set hw breakpoint */

  	{ "c", "T0*", NULL, got_break }, /* Continue */
  	{ "g", "silent", NULL, check_and_rewind_pc },

  	{ "write", "OK", write_regs },
  	{ "hw_break_val", "OK", hw_rem_write_break }, /*remove breakpoint */
  	{ "D", "OK" }, /* Detach */

  	{ "D", "OK", NULL,  got_break }, /* On success we made it here */

  	{ "", "" },
  };
  
  /*
   * Test for hitting a hw access breakpoint
   */
  static struct test_struct hw_access_break_test[] = {
  	{ "?", "S0*" }, /* Clear break points */
  	{ "hw_break_val", "OK", hw_access_break, }, /* set hw breakpoint */

  	{ "c", "T0*", NULL, got_break }, /* Continue */
  	{ "g", "silent", NULL, check_and_rewind_pc },

  	{ "write", "OK", write_regs },
  	{ "hw_break_val", "OK", hw_rem_access_break }, /*remove breakpoint */
  	{ "D", "OK" }, /* Detach */

  	{ "D", "OK", NULL,  got_break }, /* On success we made it here */

  	{ "", "" },
  };
  
  /*
   * Test for hitting a hw access breakpoint
   */
  static struct test_struct nmi_sleep_test[] = {
  	{ "?", "S0*" }, /* Clear break points */

  	{ "c", "T0*", NULL, got_break }, /* Continue */

  	{ "D", "OK" }, /* Detach */

  	{ "D", "OK", NULL,  got_break }, /* On success we made it here */

  	{ "", "" },
  };
  
  static void fill_get_buf(char *buf)
  {
  	unsigned char checksum = 0;
  	int count = 0;
  	char ch;
  
  	strcpy(get_buf, "$");
  	strcat(get_buf, buf);
  	while ((ch = buf[count])) {
  		checksum += ch;
  		count++;
  	}
  	strcat(get_buf, "#");

  	get_buf[count + 2] = hex_asc_hi(checksum);
  	get_buf[count + 3] = hex_asc_lo(checksum);

  	get_buf[count + 4] = '\0';
  	v2printk("get%i: %s
  ", ts.idx, get_buf);
  }
  
  static int validate_simple_test(char *put_str)
  {
  	char *chk_str;
  
  	if (ts.tst[ts.idx].put_handler)
  		return ts.tst[ts.idx].put_handler(put_str,
  			ts.tst[ts.idx].put);
  
  	chk_str = ts.tst[ts.idx].put;
  	if (*put_str == '$')
  		put_str++;
  
  	while (*chk_str != '\0' && *put_str != '\0') {
  		/* If someone does a * to match the rest of the string, allow

  		 * it, or stop if the received string is complete.

  		 */
  		if (*put_str == '#' || *chk_str == '*')
  			return 0;
  		if (*put_str != *chk_str)
  			return 1;
  
  		chk_str++;
  		put_str++;
  	}
  	if (*chk_str == '\0' && (*put_str == '\0' || *put_str == '#'))
  		return 0;
  
  	return 1;
  }
  
  static int run_simple_test(int is_get_char, int chr)
  {
  	int ret = 0;
  	if (is_get_char) {
  		/* Send an ACK on the get if a prior put completed and set the
  		 * send ack variable
  		 */
  		if (send_ack) {
  			send_ack = 0;
  			return '+';
  		}
  		/* On the first get char, fill the transmit buffer and then
  		 * take from the get_string.
  		 */
  		if (get_buf_cnt == 0) {
  			if (ts.tst[ts.idx].get_handler)
  				ts.tst[ts.idx].get_handler(ts.tst[ts.idx].get);
  			else
  				fill_get_buf(ts.tst[ts.idx].get);
  		}
  
  		if (get_buf[get_buf_cnt] == '\0') {

  			eprintk("kgdbts: ERROR GET: EOB on '%s' at %i
  ",

  			   ts.name, ts.idx);
  			get_buf_cnt = 0;
  			fill_get_buf("D");
  		}
  		ret = get_buf[get_buf_cnt];
  		get_buf_cnt++;
  		return ret;
  	}
  
  	/* This callback is a put char which is when kgdb sends data to
  	 * this I/O module.
  	 */

  	if (ts.tst[ts.idx].get[0] == '\0' && ts.tst[ts.idx].put[0] == '\0' &&
  	    !ts.tst[ts.idx].get_handler) {

  		eprintk("kgdbts: ERROR: beyond end of test on"

  			   " '%s' line %i
  ", ts.name, ts.idx);
  		return 0;
  	}
  
  	if (put_buf_cnt >= BUFMAX) {

  		eprintk("kgdbts: ERROR: put buffer overflow on"

  			   " '%s' line %i
  ", ts.name, ts.idx);
  		put_buf_cnt = 0;
  		return 0;
  	}
  	/* Ignore everything until the first valid packet start '$' */
  	if (put_buf_cnt == 0 && chr != '$')
  		return 0;
  
  	put_buf[put_buf_cnt] = chr;
  	put_buf_cnt++;
  
  	/* End of packet == #XX so look for the '#' */
  	if (put_buf_cnt > 3 && put_buf[put_buf_cnt - 3] == '#') {

  		if (put_buf_cnt >= BUFMAX) {
  			eprintk("kgdbts: ERROR: put buffer overflow on"
  				" '%s' line %i
  ", ts.name, ts.idx);
  			put_buf_cnt = 0;
  			return 0;
  		}

  		put_buf[put_buf_cnt] = '\0';
  		v2printk("put%i: %s
  ", ts.idx, put_buf);
  		/* Trigger check here */
  		if (ts.validate_put && ts.validate_put(put_buf)) {

  			eprintk("kgdbts: ERROR PUT: end of test "

  			   "buffer on '%s' line %i expected %s got %s
  ",
  			   ts.name, ts.idx, ts.tst[ts.idx].put, put_buf);
  		}
  		ts.idx++;
  		put_buf_cnt = 0;
  		get_buf_cnt = 0;
  		send_ack = 1;
  	}
  	return 0;
  }
  
  static void init_simple_test(void)
  {
  	memset(&ts, 0, sizeof(ts));
  	ts.run_test = run_simple_test;
  	ts.validate_put = validate_simple_test;
  }
  
  static void run_plant_and_detach_test(int is_early)
  {
  	char before[BREAK_INSTR_SIZE];
  	char after[BREAK_INSTR_SIZE];
  
  	probe_kernel_read(before, (char *)kgdbts_break_test,
  	  BREAK_INSTR_SIZE);
  	init_simple_test();
  	ts.tst = plant_and_detach_test;
  	ts.name = "plant_and_detach_test";
  	/* Activate test with initial breakpoint */
  	if (!is_early)
  		kgdb_breakpoint();
  	probe_kernel_read(after, (char *)kgdbts_break_test,
  	  BREAK_INSTR_SIZE);
  	if (memcmp(before, after, BREAK_INSTR_SIZE)) {
  		printk(KERN_CRIT "kgdbts: ERROR kgdb corrupted memory
  ");
  		panic("kgdb memory corruption");
  	}
  
  	/* complete the detach test */
  	if (!is_early)
  		kgdbts_break_test();
  }
  
  static void run_breakpoint_test(int is_hw_breakpoint)
  {
  	test_complete = 0;
  	init_simple_test();
  	if (is_hw_breakpoint) {
  		ts.tst = hw_breakpoint_test;
  		ts.name = "hw_breakpoint_test";
  	} else {
  		ts.tst = sw_breakpoint_test;
  		ts.name = "sw_breakpoint_test";
  	}
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  	/* run code with the break point in it */
  	kgdbts_break_test();
  	kgdb_breakpoint();
  
  	if (test_complete)
  		return;

  	eprintk("kgdbts: ERROR %s test failed
  ", ts.name);

  	if (is_hw_breakpoint)
  		hwbreaks_ok = 0;

  }
  
  static void run_hw_break_test(int is_write_test)
  {
  	test_complete = 0;
  	init_simple_test();
  	if (is_write_test) {
  		ts.tst = hw_write_break_test;
  		ts.name = "hw_write_break_test";
  	} else {
  		ts.tst = hw_access_break_test;
  		ts.name = "hw_access_break_test";
  	}
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  	hw_break_val_access();
  	if (is_write_test) {

  		if (test_complete == 2) {

  			eprintk("kgdbts: ERROR %s broke on access
  ",

  				ts.name);

  			hwbreaks_ok = 0;
  		}

  		hw_break_val_write();
  	}
  	kgdb_breakpoint();
  
  	if (test_complete == 1)
  		return;

  	eprintk("kgdbts: ERROR %s test failed
  ", ts.name);

  	hwbreaks_ok = 0;

  }
  
  static void run_nmi_sleep_test(int nmi_sleep)
  {
  	unsigned long flags;
  
  	init_simple_test();
  	ts.tst = nmi_sleep_test;
  	ts.name = "nmi_sleep_test";
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  	local_irq_save(flags);
  	mdelay(nmi_sleep*1000);
  	touch_nmi_watchdog();
  	local_irq_restore(flags);
  	if (test_complete != 2)

  		eprintk("kgdbts: ERROR nmi_test did not hit nmi
  ");

  	kgdb_breakpoint();
  	if (test_complete == 1)
  		return;

  	eprintk("kgdbts: ERROR %s test failed
  ", ts.name);

  }
  
  static void run_bad_read_test(void)
  {
  	init_simple_test();
  	ts.tst = bad_read_test;
  	ts.name = "bad_read_test";
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  }
  
  static void run_do_fork_test(void)
  {
  	init_simple_test();
  	ts.tst = do_fork_test;
  	ts.name = "do_fork_test";
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  }
  
  static void run_sys_open_test(void)
  {
  	init_simple_test();
  	ts.tst = sys_open_test;
  	ts.name = "sys_open_test";
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  }
  
  static void run_singlestep_break_test(void)
  {
  	init_simple_test();
  	ts.tst = singlestep_break_test;
  	ts.name = "singlestep_breakpoint_test";
  	/* Activate test with initial breakpoint */
  	kgdb_breakpoint();
  	kgdbts_break_test();
  	kgdbts_break_test();
  }
  
  static void kgdbts_run_tests(void)
  {
  	char *ptr;
  	int fork_test = 0;

  	int do_sys_open_test = 0;

  	int sstep_test = 1000;

  	int nmi_sleep = 0;

  	int i;

  	verbose = 0;
  	if (strstr(config, "V1"))
  		verbose = 1;
  	if (strstr(config, "V2"))
  		verbose = 2;

  	ptr = strchr(config, 'F');

  	if (ptr)

  		fork_test = simple_strtol(ptr + 1, NULL, 10);

  	ptr = strchr(config, 'S');

  	if (ptr)

  		do_sys_open_test = simple_strtol(ptr + 1, NULL, 10);

  	ptr = strchr(config, 'N');

  	if (ptr)
  		nmi_sleep = simple_strtol(ptr+1, NULL, 10);

  	ptr = strchr(config, 'I');

  	if (ptr)
  		sstep_test = simple_strtol(ptr+1, NULL, 10);

  	/* All HW break point tests */
  	if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) {
  		hwbreaks_ok = 1;
  		v1printk("kgdbts:RUN hw breakpoint test
  ");
  		run_breakpoint_test(1);
  		v1printk("kgdbts:RUN hw write breakpoint test
  ");
  		run_hw_break_test(1);
  		v1printk("kgdbts:RUN access write breakpoint test
  ");
  		run_hw_break_test(0);
  	}

  	/* required internal KGDB tests */
  	v1printk("kgdbts:RUN plant and detach test
  ");
  	run_plant_and_detach_test(0);
  	v1printk("kgdbts:RUN sw breakpoint test
  ");
  	run_breakpoint_test(0);
  	v1printk("kgdbts:RUN bad memory access test
  ");
  	run_bad_read_test();

  	v1printk("kgdbts:RUN singlestep test %i iterations
  ", sstep_test);
  	for (i = 0; i < sstep_test; i++) {
  		run_singlestep_break_test();
  		if (i % 100 == 0)
  			v1printk("kgdbts:RUN singlestep [%i/%i]
  ",
  				 i, sstep_test);
  	}

  
  	/* ===Optional tests=== */

  	if (nmi_sleep) {
  		v1printk("kgdbts:RUN NMI sleep %i seconds test
  ", nmi_sleep);
  		run_nmi_sleep_test(nmi_sleep);
  	}
  
  	/* If the do_fork test is run it will be the last test that is
  	 * executed because a kernel thread will be spawned at the very
  	 * end to unregister the debug hooks.
  	 */
  	if (fork_test) {
  		repeat_test = fork_test;
  		printk(KERN_INFO "kgdbts:RUN do_fork for %i breakpoints
  ",
  			repeat_test);

  		kthread_run(kgdbts_unreg_thread, NULL, "kgdbts_unreg");

  		run_do_fork_test();
  		return;
  	}
  
  	/* If the sys_open test is run it will be the last test that is
  	 * executed because a kernel thread will be spawned at the very
  	 * end to unregister the debug hooks.
  	 */

  	if (do_sys_open_test) {
  		repeat_test = do_sys_open_test;

  		printk(KERN_INFO "kgdbts:RUN sys_open for %i breakpoints
  ",
  			repeat_test);

  		kthread_run(kgdbts_unreg_thread, NULL, "kgdbts_unreg");

  		run_sys_open_test();
  		return;
  	}
  	/* Shutdown and unregister */
  	kgdb_unregister_io_module(&kgdbts_io_ops);
  	configured = 0;
  }
  
  static int kgdbts_option_setup(char *opt)
  {

  	if (strlen(opt) >= MAX_CONFIG_LEN) {

  		printk(KERN_ERR "kgdbts: config string too long
  ");
  		return -ENOSPC;
  	}
  	strcpy(config, opt);

  	return 0;
  }
  
  __setup("kgdbts=", kgdbts_option_setup);
  
  static int configure_kgdbts(void)
  {
  	int err = 0;
  
  	if (!strlen(config) || isspace(config[0]))
  		goto noconfig;

  
  	final_ack = 0;
  	run_plant_and_detach_test(1);
  
  	err = kgdb_register_io_module(&kgdbts_io_ops);
  	if (err) {
  		configured = 0;
  		return err;
  	}
  	configured = 1;
  	kgdbts_run_tests();
  
  	return err;
  
  noconfig:
  	config[0] = 0;
  	configured = 0;
  
  	return err;
  }
  
  static int __init init_kgdbts(void)
  {
  	/* Already configured? */
  	if (configured == 1)
  		return 0;
  
  	return configure_kgdbts();
  }

  device_initcall(init_kgdbts);

  static int kgdbts_get_char(void)
  {
  	int val = 0;
  
  	if (ts.run_test)
  		val = ts.run_test(1, 0);
  
  	return val;
  }
  
  static void kgdbts_put_char(u8 chr)
  {
  	if (ts.run_test)
  		ts.run_test(0, chr);
  }

  static int param_set_kgdbts_var(const char *kmessage,
  				const struct kernel_param *kp)

  {

  	size_t len = strlen(kmessage);

  
  	if (len >= MAX_CONFIG_LEN) {
  		printk(KERN_ERR "kgdbts: config string too long
  ");
  		return -ENOSPC;
  	}
  
  	/* Only copy in the string if the init function has not run yet */
  	if (configured < 0) {
  		strcpy(config, kmessage);
  		return 0;
  	}

  	if (configured == 1) {
  		printk(KERN_ERR "kgdbts: ERROR: Already configured and running.
  ");

  		return -EBUSY;
  	}
  
  	strcpy(config, kmessage);
  	/* Chop out 
   char as a result of echo */

  	if (len && config[len - 1] == '
  ')

  		config[len - 1] = '\0';

  	/* Go and configure with the new params. */
  	return configure_kgdbts();
  }
  
  static void kgdbts_pre_exp_handler(void)
  {
  	/* Increment the module count when the debugger is active */
  	if (!kgdb_connected)
  		try_module_get(THIS_MODULE);
  }
  
  static void kgdbts_post_exp_handler(void)
  {
  	/* decrement the module count when the debugger detaches */
  	if (!kgdb_connected)
  		module_put(THIS_MODULE);
  }
  
  static struct kgdb_io kgdbts_io_ops = {
  	.name			= "kgdbts",
  	.read_char		= kgdbts_get_char,
  	.write_char		= kgdbts_put_char,
  	.pre_exception		= kgdbts_pre_exp_handler,
  	.post_exception		= kgdbts_post_exp_handler,
  };

  /*
   * not really modular, but the easiest way to keep compat with existing
   * bootargs behaviour is to continue using module_param here.
   */

  module_param_call(kgdbts, param_set_kgdbts_var, param_get_string, &kps, 0644);
  MODULE_PARM_DESC(kgdbts, "<A|V1|V2>[F#|S#][N#]");