path: root/drivers/misc/kgdbts.c

/*
 * 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
 * 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>

#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