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 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 #ifdef CONFIG_SMP
 119
 120 /**
 121  * kgdb_roundup_cpus - Get other CPUs into a holding pattern
 122  * @flags: Current IRQ state
 123  *
 124  * On SMP systems, we need to get the attention of the other CPUs
 125  * and get them be in a known state.  This should do what is needed
 126  * to get the other CPUs to call kgdb_wait(). Note that on some arches,
 127  * the NMI approach is not used for rounding up all the CPUs. For example,
 128  * in case of MIPS, smp_call_function() is used to roundup CPUs. In
 129  * this case, we have to make sure that interrupts are enabled before
 130  * calling smp_call_function(). The argument to this function is
 131  * the flags that will be used when restoring the interrupts. There is
 132  * local_irq_save() call before kgdb_roundup_cpus().
 133  *
 134  * On non-SMP systems, this is not called.
 135  */
 136
 137 static void hexagon_kgdb_nmi_hook(void *ignored)
 138 {
 139         kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 140 }
 141
 142 void kgdb_roundup_cpus(unsigned long flags)
 143 {
 144         local_irq_enable();
 145         smp_call_function(hexagon_kgdb_nmi_hook, NULL, 0);
 146         local_irq_disable();
 147 }
 148 #endif
 149
 150
 151 /*  Not yet working  */
 152 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
 153                                  struct task_struct *task)
 154 {
 155         struct pt_regs *thread_regs;
 156
 157         if (task == NULL)
 158                 return;
 159
 160         /* Initialize to zero */
 161         memset(gdb_regs, 0, NUMREGBYTES);
 162
 163         /* Otherwise, we have only some registers from switch_to() */
 164         thread_regs = task_pt_regs(task);
 165         gdb_regs[0] = thread_regs->r00;
 166 }
 167
 168 /**
 169  * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
 170  * @vector: The error vector of the exception that happened.
 171  * @signo: The signal number of the exception that happened.
 172  * @err_code: The error code of the exception that happened.
 173  * @remcom_in_buffer: The buffer of the packet we have read.
 174  * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
 175  * @regs: The &struct pt_regs of the current process.
 176  *
 177  * This function MUST handle the 'c' and 's' command packets,
 178  * as well packets to set / remove a hardware breakpoint, if used.
 179  * If there are additional packets which the hardware needs to handle,
 180  * they are handled here.  The code should return -1 if it wants to
 181  * process more packets, and a %0 or %1 if it wants to exit from the
 182  * kgdb callback.
 183  *
 184  * Not yet working.
 185  */
 186 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 187                                char *remcom_in_buffer, char *remcom_out_buffer,
 188                                struct pt_regs *linux_regs)
 189 {
 190         switch (remcom_in_buffer[0]) {
 191         case 's':
 192         case 'c':
 193                 return 0;
 194         }
 195         /* Stay in the debugger. */
 196         return -1;
 197 }
 198
 199 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 200 {
 201         /* cpu roundup */
 202         if (atomic_read(&kgdb_active) != -1) {
 203                 kgdb_nmicallback(smp_processor_id(), args->regs);
 204                 return NOTIFY_STOP;
 205         }
 206
 207         if (user_mode(args->regs))
 208                 return NOTIFY_DONE;
 209
 210         if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err,
 211                                     args->regs))
 212                 return NOTIFY_DONE;
 213
 214         return NOTIFY_STOP;
 215 }
 216
 217 static int
 218 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
 219 {
 220         unsigned long flags;
 221         int ret;
 222
 223         local_irq_save(flags);
 224         ret = __kgdb_notify(ptr, cmd);
 225         local_irq_restore(flags);
 226
 227         return ret;
 228 }
 229
 230 static struct notifier_block kgdb_notifier = {
 231         .notifier_call = kgdb_notify,
 232
 233         /*
 234          * Lowest-prio notifier priority, we want to be notified last:
 235          */
 236         .priority = -INT_MAX,
 237 };
 238
 239 /**
 240  * kgdb_arch_init - Perform any architecture specific initialization.
 241  *
 242  * This function will handle the initialization of any architecture
 243  * specific callbacks.
 244  */
 245 int kgdb_arch_init(void)
 246 {
 247         return register_die_notifier(&kgdb_notifier);
 248 }
 249
 250 /**
 251  * kgdb_arch_exit - Perform any architecture specific uninitalization.
 252  *
 253  * This function will handle the uninitalization of any architecture
 254  * specific callbacks, for dynamic registration and unregistration.
 255  */
 256 void kgdb_arch_exit(void)
 257 {
 258         unregister_die_notifier(&kgdb_notifier);
 259 }