arch/hexagon/kernel/kgdb.c

   1 /*
   2  * arch/hexagon/kernel/kgdb.c - Hexagon KGDB Support
   3  *
   4  * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 and
   8  * only version 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA.
  19  */
  20
  21 #include <linux/irq.h>
  22 #include <linux/sched.h>
  23 #include <linux/sched/task_stack.h>
  24 #include <linux/kdebug.h>
  25 #include <linux/kgdb.h>
  26
  27 /* All registers are 4 bytes, for now */
  28 #define GDB_SIZEOF_REG 4
  29
  30 /* The register names are used during printing of the regs;
  31  * Keep these at three letters to pretty-print. */
  32 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
  33         { " r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, r00)},
  34         { " r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, r01)},
  35         { " r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r02)},
  36         { " r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r03)},
  37         { " r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r04)},
  38         { " r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r05)},
  39         { " r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r06)},
  40         { " r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r07)},
  41         { " r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r08)},
  42         { " r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r09)},
  43         { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10)},
  44         { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11)},
  45         { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12)},
  46         { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13)},
  47         { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14)},
  48         { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15)},
  49         { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, r16)},
  50         { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, r17)},
  51         { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, r18)},
  52         { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, r19)},
  53         { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, r20)},
  54         { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, r21)},
  55         { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, r22)},
  56         { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, r23)},
  57         { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, r24)},
  58         { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, r25)},
  59         { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, r26)},
  60         { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, r27)},
  61         { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, r28)},
  62         { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, r29)},
  63         { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, r30)},
  64         { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, r31)},
  65
  66         { "usr", GDB_SIZEOF_REG, offsetof(struct pt_regs, usr)},
  67         { "preds", GDB_SIZEOF_REG, offsetof(struct pt_regs, preds)},
  68         { " m0", GDB_SIZEOF_REG, offsetof(struct pt_regs, m0)},
  69         { " m1", GDB_SIZEOF_REG, offsetof(struct pt_regs, m1)},
  70         { "sa0", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa0)},
  71         { "sa1", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa1)},
  72         { "lc0", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc0)},
  73         { "lc1", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc1)},
  74         { " gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
  75         { "ugp", GDB_SIZEOF_REG, offsetof(struct pt_regs, ugp)},
  76         { "cs0", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs0)},
  77         { "cs1", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs1)},
  78         { "psp", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmpsp)},
  79         { "elr", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmel)},
  80         { "est", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmest)},
  81         { "badva", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmbadva)},
  82         { "restart_r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, restart_r0)},
  83         { "syscall_nr", GDB_SIZEOF_REG, offsetof(struct pt_regs, syscall_nr)},
  84 };
  85
  86 const struct kgdb_arch arch_kgdb_ops = {
  87         /* trap0(#0xDB) 0x0cdb0054 */
  88         .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c},
  89 };
  90
  91 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  92 {
  93         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  94                 return NULL;
  95
  96         *((unsigned long *) mem) = *((unsigned long *) ((void *)regs +
  97                 dbg_reg_def[regno].offset));
  98
  99         return dbg_reg_def[regno].name;
 100 }
 101
 102 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
 103 {
 104         if (regno >= DBG_MAX_REG_NUM || regno < 0)
 105                 return -EINVAL;
 106
 107         *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) =
 108                 *((unsigned long *) mem);
 109
 110         return 0;
 111 }
 112
 113 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 114 {
 115         instruction_pointer(regs) = pc;
 116 }
 117
 118
 119 /*  Not yet working  */
 120 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
 121                                  struct task_struct *task)
 122 {
 123         struct pt_regs *thread_regs;
 124
 125         if (task == NULL)
 126                 return;
 127
 128         /* Initialize to zero */
 129         memset(gdb_regs, 0, NUMREGBYTES);
 130
 131         /* Otherwise, we have only some registers from switch_to() */
 132         thread_regs = task_pt_regs(task);
 133         gdb_regs[0] = thread_regs->r00;
 134 }
 135
 136 /**
 137  * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
 138  * @vector: The error vector of the exception that happened.
 139  * @signo: The signal number of the exception that happened.
 140  * @err_code: The error code of the exception that happened.
 141  * @remcom_in_buffer: The buffer of the packet we have read.
 142  * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
 143  * @regs: The &struct pt_regs of the current process.
 144  *
 145  * This function MUST handle the 'c' and 's' command packets,
 146  * as well packets to set / remove a hardware breakpoint, if used.
 147  * If there are additional packets which the hardware needs to handle,
 148  * they are handled here.  The code should return -1 if it wants to
 149  * process more packets, and a %0 or %1 if it wants to exit from the
 150  * kgdb callback.
 151  *
 152  * Not yet working.
 153  */
 154 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 155                                char *remcom_in_buffer, char *remcom_out_buffer,
 156                                struct pt_regs *linux_regs)
 157 {
 158         switch (remcom_in_buffer[0]) {
 159         case 's':
 160         case 'c':
 161                 return 0;
 162         }
 163         /* Stay in the debugger. */
 164         return -1;
 165 }
 166
 167 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 168 {
 169         /* cpu roundup */
 170         if (atomic_read(&kgdb_active) != -1) {
 171                 kgdb_nmicallback(smp_processor_id(), args->regs);
 172                 return NOTIFY_STOP;
 173         }
 174
 175         if (user_mode(args->regs))
 176                 return NOTIFY_DONE;
 177
 178         if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err,
 179                                     args->regs))
 180                 return NOTIFY_DONE;
 181
 182         return NOTIFY_STOP;
 183 }
 184
 185 static int
 186 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
 187 {
 188         unsigned long flags;
 189         int ret;
 190
 191         local_irq_save(flags);
 192         ret = __kgdb_notify(ptr, cmd);
 193         local_irq_restore(flags);
 194
 195         return ret;
 196 }
 197
 198 static struct notifier_block kgdb_notifier = {
 199         .notifier_call = kgdb_notify,
 200
 201         /*
 202          * Lowest-prio notifier priority, we want to be notified last:
 203          */
 204         .priority = -INT_MAX,
 205 };
 206
 207 /**
 208  * kgdb_arch_init - Perform any architecture specific initialization.
 209  *
 210  * This function will handle the initialization of any architecture
 211  * specific callbacks.
 212  */
 213 int kgdb_arch_init(void)
 214 {
 215         return register_die_notifier(&kgdb_notifier);
 216 }
 217
 218 /**
 219  * kgdb_arch_exit - Perform any architecture specific uninitalization.
 220  *
 221  * This function will handle the uninitalization of any architecture
 222  * specific callbacks, for dynamic registration and unregistration.
 223  */
 224 void kgdb_arch_exit(void)
 225 {
 226         unregister_die_notifier(&kgdb_notifier);
 227 }