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 } 228