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/kdebug.h>
  24 #include <linux/kgdb.h>
  25
  26 /* All registers are 4 bytes, for now */
  27 #define GDB_SIZEOF_REG 4
  28
  29 /* The register names are used during printing of the regs;
  30  * Keep these at three letters to pretty-print. */
  31 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
  32         { " r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, r00)},
  33         { " r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, r01)},
  34         { " r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r02)},
  35         { " r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r03)},
  36         { " r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r04)},
  37         { " r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r05)},
  38         { " r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r06)},
  39         { " r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r07)},
  40         { " r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r08)},
  41         { " r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r09)},
  42         { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10)},
  43         { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11)},
  44         { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12)},
  45         { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13)},
  46         { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14)},
  47         { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15)},
  48         { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, r16)},
  49         { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, r17)},
  50         { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, r18)},
  51         { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, r19)},
  52         { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, r20)},
  53         { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, r21)},
  54         { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, r22)},
  55         { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, r23)},
  56         { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, r24)},
  57         { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, r25)},
  58         { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, r26)},
  59         { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, r27)},
  60         { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, r28)},
  61         { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, r29)},
  62         { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, r30)},
  63         { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, r31)},
  64
  65         { "usr", GDB_SIZEOF_REG, offsetof(struct pt_regs, usr)},
  66         { "preds", GDB_SIZEOF_REG, offsetof(struct pt_regs, preds)},
  67         { " m0", GDB_SIZEOF_REG, offsetof(struct pt_regs, m0)},
  68         { " m1", GDB_SIZEOF_REG, offsetof(struct pt_regs, m1)},
  69         { "sa0", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa0)},
  70         { "sa1", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa1)},
  71         { "lc0", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc0)},
  72         { "lc1", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc1)},
  73         { " gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
  74         { "ugp", GDB_SIZEOF_REG, offsetof(struct pt_regs, ugp)},
  75         { "cs0", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs0)},
  76         { "cs1", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs1)},
  77         { "psp", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmpsp)},
  78         { "elr", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmel)},
  79         { "est", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmest)},
  80         { "badva", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmbadva)},
  81         { "restart_r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, restart_r0)},
  82         { "syscall_nr", GDB_SIZEOF_REG, offsetof(struct pt_regs, syscall_nr)},
  83 };
  84
  85 struct kgdb_arch arch_kgdb_ops = {
  86         /* trap0(#0xDB) 0x0cdb0054 */
  87         .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c},
  88 };
  89
  90 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  91 {
  92         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  93                 return NULL;
  94
  95         *((unsigned long *) mem) = *((unsigned long *) ((void *)regs +
  96                 dbg_reg_def[regno].offset));
  97
  98         return dbg_reg_def[regno].name;
  99 }
 100
 101 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
 102 {
 103         if (regno >= DBG_MAX_REG_NUM || regno < 0)
 104                 return -EINVAL;
 105
 106         *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) =
 107                 *((unsigned long *) mem);
 108
 109         return 0;
 110 }
 111
 112 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 113 {
 114         instruction_pointer(regs) = pc;
 115 }
 116
 117 #ifdef CONFIG_SMP
 118
 119 /**
 120  * kgdb_roundup_cpus - Get other CPUs into a holding pattern
 121  * @flags: Current IRQ state
 122  *
 123  * On SMP systems, we need to get the attention of the other CPUs
 124  * and get them be in a known state.  This should do what is needed
 125  * to get the other CPUs to call kgdb_wait(). Note that on some arches,
 126  * the NMI approach is not used for rounding up all the CPUs. For example,
 127  * in case of MIPS, smp_call_function() is used to roundup CPUs. In
 128  * this case, we have to make sure that interrupts are enabled before
 129  * calling smp_call_function(). The argument to this function is
 130  * the flags that will be used when restoring the interrupts. There is
 131  * local_irq_save() call before kgdb_roundup_cpus().
 132  *
 133  * On non-SMP systems, this is not called.
 134  */
 135
 136 static void hexagon_kgdb_nmi_hook(void *ignored)
 137 {
 138         kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 139 }
 140
 141 void kgdb_roundup_cpus(unsigned long flags)
 142 {
 143         local_irq_enable();
 144         smp_call_function(hexagon_kgdb_nmi_hook, NULL, 0);
 145         local_irq_disable();
 146 }
 147 #endif
 148
 149
 150 /*  Not yet working  */
 151 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
 152                                  struct task_struct *task)
 153 {
 154         struct pt_regs *thread_regs;
 155
 156         if (task == NULL)
 157                 return;
 158
 159         /* Initialize to zero */
 160         memset(gdb_regs, 0, NUMREGBYTES);
 161
 162         /* Otherwise, we have only some registers from switch_to() */
 163         thread_regs = task_pt_regs(task);
 164         gdb_regs[0] = thread_regs->r00;
 165 }
 166
 167 /**
 168  * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
 169  * @vector: The error vector of the exception that happened.
 170  * @signo: The signal number of the exception that happened.
 171  * @err_code: The error code of the exception that happened.
 172  * @remcom_in_buffer: The buffer of the packet we have read.
 173  * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
 174  * @regs: The &struct pt_regs of the current process.
 175  *
 176  * This function MUST handle the 'c' and 's' command packets,
 177  * as well packets to set / remove a hardware breakpoint, if used.
 178  * If there are additional packets which the hardware needs to handle,
 179  * they are handled here.  The code should return -1 if it wants to
 180  * process more packets, and a %0 or %1 if it wants to exit from the
 181  * kgdb callback.
 182  *
 183  * Not yet working.
 184  */
 185 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 186                                char *remcom_in_buffer, char *remcom_out_buffer,
 187                                struct pt_regs *linux_regs)
 188 {
 189         switch (remcom_in_buffer[0]) {
 190         case 's':
 191         case 'c':
 192                 return 0;
 193         }
 194         /* Stay in the debugger. */
 195         return -1;
 196 }
 197
 198 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 199 {
 200         /* cpu roundup */
 201         if (atomic_read(&kgdb_active) != -1) {
 202                 kgdb_nmicallback(smp_processor_id(), args->regs);
 203                 return NOTIFY_STOP;
 204         }
 205
 206         if (user_mode(args->regs))
 207                 return NOTIFY_DONE;
 208
 209         if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err,
 210                                     args->regs))
 211                 return NOTIFY_DONE;
 212
 213         return NOTIFY_STOP;
 214 }
 215
 216 static int
 217 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
 218 {
 219         unsigned long flags;
 220         int ret;
 221
 222         local_irq_save(flags);
 223         ret = __kgdb_notify(ptr, cmd);
 224         local_irq_restore(flags);
 225
 226         return ret;
 227 }
 228
 229 static struct notifier_block kgdb_notifier = {
 230         .notifier_call = kgdb_notify,
 231
 232         /*
 233          * Lowest-prio notifier priority, we want to be notified last:
 234          */
 235         .priority = -INT_MAX,
 236 };
 237
 238 /**
 239  * kgdb_arch_init - Perform any architecture specific initialization.
 240  *
 241  * This function will handle the initialization of any architecture
 242  * specific callbacks.
 243  */
 244 int kgdb_arch_init(void)
 245 {
 246         return register_die_notifier(&kgdb_notifier);
 247 }
 248
 249 /**
 250  * kgdb_arch_exit - Perform any architecture specific uninitalization.
 251  *
 252  * This function will handle the uninitalization of any architecture
 253  * specific callbacks, for dynamic registration and unregistration.
 254  */
 255 void kgdb_arch_exit(void)
 256 {
 257         unregister_die_notifier(&kgdb_notifier);
 258 }