kgdb: add kgdb internal test suite

This patch adds regression tests for testing the kgdb core and arch
specific implementation.

The kgdb test suite is designed to be built into the kernel and not as
a module because it uses a number of low level kernel and kgdb
primitives which should not be exported externally.

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

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

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/misc/Makefile

@@ -22,3 +22,4 @@ obj-$(CONFIG_FUJITSU_LAPTOP)	+= fujitsu-laptop.o
 obj-$(CONFIG_EEPROM_93CX6)	+= eeprom_93cx6.o
 obj-$(CONFIG_INTEL_MENLOW)	+= intel_menlow.o
 obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o
+obj-$(CONFIG_KGDB_TESTS)	+= kgdbts.o

drivers/misc/kgdbts.c

@@ -0,0 +1,1083 @@
+/*
+ * 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.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+/* 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
+ *
+ * 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/delay.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 MAX_CONFIG_LEN		40
+
+static const char hexchars[] = "0123456789abcdef";
+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 hw_break_val;
+static int hw_break_val2;
+#if defined(CONFIG_ARM) || defined(CONFIG_MIPS)
+static int arch_needs_sstep_emulation = 1;
+#else
+static int arch_needs_sstep_emulation;
+#endif
+static unsigned long sstep_addr;
+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;
+
+static char config[MAX_CONFIG_LEN];
+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);
+
+	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\n");
+}
+
+/* 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)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;
+	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("Z0", arg, 0);
+}
+
+static void sw_rem_break(char *arg)
+{
+	break_helper("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 check_and_rewind_pc(char *put_str, char *arg)
+{
+	unsigned long addr = lookup_addr(arg);
+	int offset = 0;
+
+	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\n", instruction_pointer(&kgdbts_regs));
+#ifdef CONFIG_X86
+	/* On x86 a breakpoint stop requires it to be decremented */
+	if (addr + 1 == kgdbts_regs.ip)
+		offset = -1;
+#endif
+	if (strcmp(arg, "silent") &&
+		instruction_pointer(&kgdbts_regs) + offset != addr) {
+		printk(KERN_ERR "kgdbts: BP mismatch %lx expected %lx\n",
+			   instruction_pointer(&kgdbts_regs) + offset, addr);
+		return 1;
+	}
+#ifdef CONFIG_X86
+	/* On x86 adjust the instruction pointer if needed */
+	kgdbts_regs.ip += offset;
+#endif
+	return 0;
+}
+
+static int check_single_step(char *put_str, char *arg)
+{
+	unsigned long addr = lookup_addr(arg);
+	/*
+	 * 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\n",
+		   instruction_pointer(&kgdbts_regs));
+	if (instruction_pointer(&kgdbts_regs) == addr) {
+		printk(KERN_ERR "kgdbts: SingleStep failed at %lx\n",
+			   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
+		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 emul_sstep_get(char *arg)
+{
+	if (!arch_needs_sstep_emulation) {
+		fill_get_buf(arg);
+		return;
+	}
+	switch (sstep_state) {
+	case 0:
+		v2printk("Emulate single step\n");
+		/* Start by looking at the current PC */
+		fill_get_buf("g");
+		break;
+	case 1:
+		/* set breakpoint */
+		break_helper("Z0", 0, sstep_addr);
+		break;
+	case 2:
+		/* Continue */
+		fill_get_buf("c");
+		break;
+	case 3:
+		/* Clear breakpoint */
+		break_helper("z0", 0, sstep_addr);
+		break;
+	default:
+		printk(KERN_ERR "kgdbts: ERROR failed sstep get emulation\n");
+	}
+	sstep_state++;
+}
+
+static int emul_sstep_put(char *put_str, char *arg)
+{
+	if (!arch_needs_sstep_emulation) {
+		if (!strncmp(put_str+1, arg, 2))
+			return 0;
+		return 1;
+	}
+	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\n",
+			 instruction_pointer(&kgdbts_regs));
+		/* Want to stop at IP + break instruction size by default */
+		sstep_addr = instruction_pointer(&kgdbts_regs) +
+			BREAK_INSTR_SIZE;
+		break;
+	case 2:
+		if (strncmp(put_str, "$OK", 3)) {
+			printk(KERN_ERR "kgdbts: failed sstep break set\n");
+			return 1;
+		}
+		break;
+	case 3:
+		if (strncmp(put_str, "$T0", 3)) {
+			printk(KERN_ERR "kgdbts: failed continue sstep\n");
+			return 1;
+		}
+		break;
+	case 4:
+		if (strncmp(put_str, "$OK", 3)) {
+			printk(KERN_ERR "kgdbts: failed sstep break unset\n");
+			return 1;
+		}
+		/* Single step is complete so continue on! */
+		sstep_state = 0;
+		return 0;
+	default:
+		printk(KERN_ERR "kgdbts: ERROR failed sstep put emulation\n");
+	}
+
+	/* 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", 0, check_and_rewind_pc },
+	{ "write", "OK", write_regs },
+	{ "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
+	{ "D", "OK" }, /* Detach */
+	{ "D", "OK", 0,  got_break }, /* If the test worked 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*", }, /* Continue */
+	{ "g", "kgdbts_break_test", 0, check_and_rewind_pc },
+	{ "write", "OK", write_regs }, /* Write registers */
+	{ "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */
+	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
+	{ "g", "kgdbts_break_test", 0, check_single_step },
+	{ "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */
+	{ "c", "T0*", }, /* Continue */
+	{ "g", "kgdbts_break_test", 0, 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*", }, /* Continue */
+	{ "g", "do_fork", 0, check_and_rewind_pc }, /* check location */
+	{ "write", "OK", write_regs }, /* Write registers */
+	{ "do_fork", "OK", sw_rem_break }, /*remove breakpoint */
+	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
+	{ "g", "do_fork", 0, check_single_step },
+	{ "do_fork", "OK", sw_break, }, /* set sw breakpoint */
+	{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
+	{ "D", "OK", 0, final_ack_set }, /* detach and unregister I/O */
+	{ "", "" },
+};
+
+/* 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*", }, /* Continue */
+	{ "g", "sys_open", 0, check_and_rewind_pc }, /* check location */
+	{ "write", "OK", write_regs }, /* Write registers */
+	{ "sys_open", "OK", sw_rem_break }, /*remove breakpoint */
+	{ "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */
+	{ "g", "sys_open", 0, check_single_step },
+	{ "sys_open", "OK", sw_break, }, /* set sw breakpoint */
+	{ "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */
+	{ "D", "OK", 0, final_ack_set }, /* detach and unregister I/O */
+	{ "", "" },
+};
+
+/*
+ * 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", 0, check_and_rewind_pc },
+	{ "write", "OK", write_regs },
+	{ "kgdbts_break_test", "OK", hw_rem_break }, /*remove breakpoint */
+	{ "D", "OK" }, /* Detach */
+	{ "D", "OK", 0,  got_break }, /* If the test worked 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*", 0, got_break }, /* Continue */
+	{ "g", "silent", 0, check_and_rewind_pc },
+	{ "write", "OK", write_regs },
+	{ "hw_break_val", "OK", hw_rem_write_break }, /*remove breakpoint */
+	{ "D", "OK" }, /* Detach */
+	{ "D", "OK", 0,  got_break }, /* If the test worked 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*", 0, got_break }, /* Continue */
+	{ "g", "silent", 0, check_and_rewind_pc },
+	{ "write", "OK", write_regs },
+	{ "hw_break_val", "OK", hw_rem_access_break }, /*remove breakpoint */
+	{ "D", "OK" }, /* Detach */
+	{ "D", "OK", 0,  got_break }, /* If the test worked we made it here */
+	{ "", "" },
+};
+
+/*
+ * Test for hitting a hw access breakpoint
+ */
+static struct test_struct nmi_sleep_test[] = {
+	{ "?", "S0*" }, /* Clear break points */
+	{ "c", "T0*", 0, got_break }, /* Continue */
+	{ "D", "OK" }, /* Detach */
+	{ "D", "OK", 0,  got_break }, /* If the test worked 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] = hexchars[checksum >> 4];
+	get_buf[count + 3] = hexchars[checksum & 0xf];
+	get_buf[count + 4] = '\0';
+	v2printk("get%i: %s\n", 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 == '$')
+		put_str++;
+
+	while (*chk_str != '\0' && *put_str != '\0') {
+		/* If someone does a * to match the rest of the string, allow
+		 * it, or stop if the recieved string is complete.
+		 */
+		if (*put_str == '#' || *chk_str == '*')
+			return 0;
+		if (*put_str != *chk_str)
+			return 1;
+
+		chk_str++;
+		put_str++;
+	}
+	if (*chk_str == '\0' && (*put_str == '\0' || *put_str == '#'))
+		return 0;
+
+	return 1;
+}
+
+static int run_simple_test(int is_get_char, int chr)
+{
+	int ret = 0;
+	if (is_get_char) {
+		/* Send an ACK on the get if a prior put completed and set the
+		 * send ack variable
+		 */
+		if (send_ack) {
+			send_ack = 0;
+			return '+';
+		}
+		/* On the first get char, fill the transmit buffer and then
+		 * take from the get_string.
+		 */
+		if (get_buf_cnt == 0) {
+			if (ts.tst[ts.idx].get_handler)
+				ts.tst[ts.idx].get_handler(ts.tst[ts.idx].get);
+			else
+				fill_get_buf(ts.tst[ts.idx].get);
+		}
+
+		if (get_buf[get_buf_cnt] == '\0') {
+			printk(KERN_ERR
+			   "kgdbts: ERROR GET: end of buffer on '%s' at %i\n",
+			   ts.name, ts.idx);
+			get_buf_cnt = 0;
+			fill_get_buf("D");
+		}
+		ret = get_buf[get_buf_cnt];
+		get_buf_cnt++;
+		return ret;
+	}
+
+	/* This callback is a put char which is when kgdb sends data to
+	 * this I/O module.
+	 */
+	if (ts.tst[ts.idx].get[0] == '\0' &&
+		ts.tst[ts.idx].put[0] == '\0') {
+		printk(KERN_ERR "kgdbts: ERROR: beyond end of test on"
+			   " '%s' line %i\n", ts.name, ts.idx);
+		return 0;
+	}
+
+	if (put_buf_cnt >= BUFMAX) {
+		printk(KERN_ERR "kgdbts: ERROR: put buffer overflow on"
+			   " '%s' line %i\n", ts.name, ts.idx);
+		put_buf_cnt = 0;
+		return 0;
+	}
+	/* Ignore everything until the first valid packet start '$' */
+	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] == '#') {
+		put_buf[put_buf_cnt] = '\0';
+		v2printk("put%i: %s\n", ts.idx, put_buf);
+		/* Trigger check here */
+		if (ts.validate_put && ts.validate_put(put_buf)) {
+			printk(KERN_ERR "kgdbts: ERROR PUT: end of test "
+			   "buffer on '%s' line %i expected %s got %s\n",
+			   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\n");
+		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;
+
+	printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name);
+}
+
+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)
+			printk(KERN_ERR "kgdbts: ERROR %s broke on access\n",
+				ts.name);
+		hw_break_val_write();
+	}
+	kgdb_breakpoint();
+
+	if (test_complete == 1)
+		return;
+
+	printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name);
+}
+
+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)
+		printk(KERN_ERR "kgdbts: ERROR nmi_test did not hit nmi\n");
+	kgdb_breakpoint();
+	if (test_complete == 1)
+		return;
+
+	printk(KERN_ERR "kgdbts: ERROR %s test failed\n", 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 sys_open_test = 0;
+	int nmi_sleep = 0;
+
+	ptr = strstr(config, "F");
+	if (ptr)
+		fork_test = simple_strtol(ptr+1, NULL, 10);
+	ptr = strstr(config, "S");
+	if (ptr)
+		sys_open_test = simple_strtol(ptr+1, NULL, 10);
+	ptr = strstr(config, "N");
+	if (ptr)
+		nmi_sleep = simple_strtol(ptr+1, NULL, 10);
+
+	/* required internal KGDB tests */
+	v1printk("kgdbts:RUN plant and detach test\n");
+	run_plant_and_detach_test(0);
+	v1printk("kgdbts:RUN sw breakpoint test\n");
+	run_breakpoint_test(0);
+	v1printk("kgdbts:RUN bad memory access test\n");
+	run_bad_read_test();
+	v1printk("kgdbts:RUN singlestep breakpoint test\n");
+	run_singlestep_break_test();
+
+	/* ===Optional tests=== */
+
+	/* All HW break point tests */
+	if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) {
+		v1printk("kgdbts:RUN hw breakpoint test\n");
+		run_breakpoint_test(1);
+		v1printk("kgdbts:RUN hw write breakpoint test\n");
+		run_hw_break_test(1);
+		v1printk("kgdbts:RUN access write breakpoint test\n");
+		run_hw_break_test(0);
+	}
+
+	if (nmi_sleep) {
+		v1printk("kgdbts:RUN NMI sleep %i seconds test\n", 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\n",
+			repeat_test);
+		kthread_run(kgdbts_unreg_thread, 0, "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 (sys_open_test) {
+		repeat_test = sys_open_test;
+		printk(KERN_INFO "kgdbts:RUN sys_open for %i breakpoints\n",
+			repeat_test);
+		kthread_run(kgdbts_unreg_thread, 0, "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\n");
+		return -ENOSPC;
+	}
+	strcpy(config, opt);
+
+	verbose = 0;
+	if (strstr(config, "V1"))
+		verbose = 1;
+	if (strstr(config, "V2"))
+		verbose = 2;
+
+	return 0;
+}
+
+__setup("kgdbts=", kgdbts_option_setup);
+
+static int configure_kgdbts(void)
+{
+	int err = 0;
+
+	if (!strlen(config) || isspace(config[0]))
+		goto noconfig;
+	err = kgdbts_option_setup(config);
+	if (err)
+		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();
+}
+
+static void cleanup_kgdbts(void)
+{
+	if (configured == 1)
+		kgdb_unregister_io_module(&kgdbts_io_ops);
+}
+
+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, struct kernel_param *kp)
+{
+	int len = strlen(kmessage);
+
+	if (len >= MAX_CONFIG_LEN) {
+		printk(KERN_ERR "kgdbts: config string too long\n");
+		return -ENOSPC;
+	}
+
+	/* Only copy in the string if the init function has not run yet */
+	if (configured < 0) {
+		strcpy(config, kmessage);
+		return 0;
+	}
+
+	if (kgdb_connected) {
+		printk(KERN_ERR
+	       "kgdbts: Cannot reconfigure while KGDB is connected.\n");
+
+		return -EBUSY;
+	}
+
+	strcpy(config, kmessage);
+	/* Chop out \n char as a result of echo */
+	if (config[len - 1] == '\n')
+		config[len - 1] = '\0';
+
+	if (configured == 1)
+		cleanup_kgdbts();
+
+	/* 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,
+};
+
+module_init(init_kgdbts);
+module_exit(cleanup_kgdbts);
+module_param_call(kgdbts, param_set_kgdbts_var, param_get_string, &kps, 0644);
+MODULE_PARM_DESC(kgdbts, "<A|V1|V2>[F#|S#][N#]");
+MODULE_DESCRIPTION("KGDB Test Suite");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Wind River Systems, Inc.");
+

lib/Kconfig.kgdb

@@ -25,3 +25,16 @@ config KGDB_SERIAL_CONSOLE
 	help
 	  Share a serial console with kgdb. Sysrq-g must be used
 	  to break in initially.
+
+config KGDB_TESTS
+	bool "KGDB: internal test suite"
+	depends on KGDB
+	default n
+	help
+	  This is a kgdb I/O module specifically designed to test
+	  kgdb's internal functions.  This kgdb I/O module is
+	  intended to for the development of new kgdb stubs
+	  as well as regression testing the kgdb internals.
+	  See the drivers/misc/kgdbts.c for the details about
+	  the tests.  The most basic of this I/O module is to boot
+	  a kernel boot arguments "kgdbwait kgdbts=V1F100"