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 // 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 kernel_clone for ## iterations
  * S## = Break at sys_open for ## iterations
  * I## = Run the single step test ## iterations
  *
  * NOTE: that the kernel_clone 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 kernel_clone
  * 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 kernel_clone
  * 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 <linux/kallsyms.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\n");
 }
 
 /*
  * This is a cached wrapper for kallsyms_lookup_name().
  *
  * The cache is a big win for several tests. For example it more the doubles
  * the cycles per second during the sys_open test. This is not theoretic,
  * the performance improvement shows up at human scale, especially when
  * testing using emulators.
  *
  * Obviously neither re-entrant nor thread-safe but that is OK since it
  * can only be called from the debug trap (and therefore all other CPUs
  * are halted).
  */
 static unsigned long lookup_addr(char *arg)
 {
     static char cached_arg[KSYM_NAME_LEN];
     static unsigned long cached_addr;
 
     if (strcmp(arg, cached_arg)) {
         strscpy(cached_arg, arg, KSYM_NAME_LEN);
         cached_addr = kallsyms_lookup_name(arg);
     }
 
     return (unsigned long)dereference_function_descriptor(
             (void *)cached_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\n", 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, "do_sys_openat2") || !strcmp(arg, "kernel_clone")))) {
         /* This is special case for emulated single step */
         v2printk("Emul: rewind hit single step bp\n");
         restart_from_top_after_write = 1;
     } else if (strcmp(arg, "silent") && ip + offset != addr) {
         eprintk("kgdbts: BP mismatch %lx expected %lx\n",
                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\n",
            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\n", 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\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 {
         if (repeat_test % 100 == 0)
             v1printk("kgdbts:RUN ... %d remaining\n", 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\n", 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\n");
         /* 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\n");
     }
     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\n",
              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, "$OK", 3)) {
             eprintk("kgdbts: failed sstep break set\n");
             return 1;
         }
         break;
     case 3:
         if (strncmp(put_str, "$T0", 3)) {
             eprintk("kgdbts: failed continue sstep\n");
             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\n");
             return 1;
         }
         /* Single step is complete so continue on! */
         sstep_state = 0;
         return 0;
     default:
         eprintk("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", 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 kernel_clone for what ever the number
  * of iterations required by the variable repeat_test.
  */
 static struct test_struct do_kernel_clone_test[] = {
     { "?", "S0*" }, /* Clear break points */
     { "kernel_clone", "OK", sw_break, }, /* set sw breakpoint */
     { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
     { "kernel_clone", "OK", sw_rem_break }, /*remove breakpoint */
     { "g", "kernel_clone", 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", "kernel_clone", NULL, check_single_step },
     { "kernel_clone", "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 */
     { "do_sys_openat2", "OK", sw_break, }, /* set sw breakpoint */
     { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */
     { "do_sys_openat2", "OK", sw_rem_break }, /*remove breakpoint */
     { "g", "do_sys_openat2", 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_sys_openat2", NULL, check_single_step },
     { "do_sys_openat2", "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\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 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\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' &&
         !ts.tst[ts.idx].get_handler) {
         eprintk("kgdbts: ERROR: beyond end of test on"
                " '%s' line %i\n", ts.name, ts.idx);
         return 0;
     }
 
     if (put_buf_cnt >= BUFMAX) {
         eprintk("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] == '#') {
         if (put_buf_cnt >= BUFMAX) {
             eprintk("kgdbts: ERROR: put buffer overflow on"
                 " '%s' line %i\n", ts.name, ts.idx);
             put_buf_cnt = 0;
             return 0;
         }
         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)) {
             eprintk("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];
 
     copy_from_kernel_nofault(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();
     copy_from_kernel_nofault(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;
 
     eprintk("kgdbts: ERROR %s test failed\n", 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\n",
                 ts.name);
             hwbreaks_ok = 0;
         }
         hw_break_val_write();
     }
     kgdb_breakpoint();
 
     if (test_complete == 1)
         return;
 
     eprintk("kgdbts: ERROR %s test failed\n", 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\n");
     kgdb_breakpoint();
     if (test_complete == 1)
         return;
 
     eprintk("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_kernel_clone_test(void)
 {
     init_simple_test();
     ts.tst = do_kernel_clone_test;
     ts.name = "do_kernel_clone_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 clone_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)
         clone_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\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);
     }
 
     /* 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 test %i iterations\n", sstep_test);
     for (i = 0; i < sstep_test; i++) {
         run_singlestep_break_test();
         if (i % 100 == 0)
             v1printk("kgdbts:RUN singlestep [%i/%i]\n",
                  i, sstep_test);
     }
 
     /* ===Optional tests=== */
 
     if (nmi_sleep) {
         v1printk("kgdbts:RUN NMI sleep %i seconds test\n", nmi_sleep);
         run_nmi_sleep_test(nmi_sleep);
     }
 
     /* If the kernel_clone 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 (clone_test) {
         repeat_test = clone_test;
         printk(KERN_INFO "kgdbts:RUN kernel_clone for %i breakpoints\n",
             repeat_test);
         kthread_run(kgdbts_unreg_thread, NULL, "kgdbts_unreg");
         run_kernel_clone_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\n",
             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\n");
         return 1;
     }
     strcpy(config, opt);
     return 1;
 }
 
 __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\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 (configured == 1) {
         printk(KERN_ERR "kgdbts: ERROR: Already configured and running.\n");
         return -EBUSY;
     }
 
     strcpy(config, kmessage);
     /* Chop out \n char as a result of echo */
     if (len && config[len - 1] == '\n')
         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#]");

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