1 /* 2 * arch/hexagon/kernel/kgdb.c - Hexagon KGDB Support 3 * 4 * Copyright (c) 2011, 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/kdebug.h> 22 #include <linux/kgdb.h> 23 24 /* All registers are 4 bytes, for now */ 25 #define GDB_SIZEOF_REG 4 26 27 /* The register names are used during printing of the regs; 28 * Keep these at three letters to pretty-print. */ 29 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { 30 { " r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, r00)}, 31 { " r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, r01)}, 32 { " r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r02)}, 33 { " r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r03)}, 34 { " r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r04)}, 35 { " r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r05)}, 36 { " r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r06)}, 37 { " r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r07)}, 38 { " r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r08)}, 39 { " r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r09)}, 40 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10)}, 41 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11)}, 42 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12)}, 43 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13)}, 44 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14)}, 45 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15)}, 46 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, r16)}, 47 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, r17)}, 48 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, r18)}, 49 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, r19)}, 50 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, r20)}, 51 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, r21)}, 52 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, r22)}, 53 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, r23)}, 54 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, r24)}, 55 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, r25)}, 56 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, r26)}, 57 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, r27)}, 58 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, r28)}, 59 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, r29)}, 60 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, r30)}, 61 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, r31)}, 62 63 { "usr", GDB_SIZEOF_REG, offsetof(struct pt_regs, usr)}, 64 { "preds", GDB_SIZEOF_REG, offsetof(struct pt_regs, preds)}, 65 { " m0", GDB_SIZEOF_REG, offsetof(struct pt_regs, m0)}, 66 { " m1", GDB_SIZEOF_REG, offsetof(struct pt_regs, m1)}, 67 { "sa0", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa0)}, 68 { "sa1", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa1)}, 69 { "lc0", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc0)}, 70 { "lc1", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc1)}, 71 { " gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)}, 72 { "ugp", GDB_SIZEOF_REG, offsetof(struct pt_regs, ugp)}, 73 { "psp", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmpsp)}, 74 { "elr", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmel)}, 75 { "est", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmest)}, 76 { "badva", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmbadva)}, 77 { "restart_r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, restart_r0)}, 78 { "syscall_nr", GDB_SIZEOF_REG, offsetof(struct pt_regs, syscall_nr)}, 79 }; 80 81 struct kgdb_arch arch_kgdb_ops = { 82 /* trap0(#0xDB) 0x0cdb0054 */ 83 .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c}, 84 }; 85 86 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 87 { 88 if (regno >= DBG_MAX_REG_NUM || regno < 0) 89 return NULL; 90 91 *((unsigned long *) mem) = *((unsigned long *) ((void *)regs + 92 dbg_reg_def[regno].offset)); 93 94 return dbg_reg_def[regno].name; 95 } 96 97 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 98 { 99 if (regno >= DBG_MAX_REG_NUM || regno < 0) 100 return -EINVAL; 101 102 *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) = 103 *((unsigned long *) mem); 104 105 return 0; 106 } 107 108 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 109 { 110 instruction_pointer(regs) = pc; 111 } 112 113 #ifdef CONFIG_SMP 114 115 /** 116 * kgdb_roundup_cpus - Get other CPUs into a holding pattern 117 * @flags: Current IRQ state 118 * 119 * On SMP systems, we need to get the attention of the other CPUs 120 * and get them be in a known state. This should do what is needed 121 * to get the other CPUs to call kgdb_wait(). Note that on some arches, 122 * the NMI approach is not used for rounding up all the CPUs. For example, 123 * in case of MIPS, smp_call_function() is used to roundup CPUs. In 124 * this case, we have to make sure that interrupts are enabled before 125 * calling smp_call_function(). The argument to this function is 126 * the flags that will be used when restoring the interrupts. There is 127 * local_irq_save() call before kgdb_roundup_cpus(). 128 * 129 * On non-SMP systems, this is not called. 130 */ 131 132 static void hexagon_kgdb_nmi_hook(void *ignored) 133 { 134 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); 135 } 136 137 void kgdb_roundup_cpus(unsigned long flags) 138 { 139 local_irq_enable(); 140 smp_call_function(hexagon_kgdb_nmi_hook, NULL, 0); 141 local_irq_disable(); 142 } 143 #endif 144 145 146 /* Not yet working */ 147 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, 148 struct task_struct *task) 149 { 150 struct pt_regs *thread_regs; 151 152 if (task == NULL) 153 return; 154 155 /* Initialize to zero */ 156 memset(gdb_regs, 0, NUMREGBYTES); 157 158 /* Otherwise, we have only some registers from switch_to() */ 159 thread_regs = task_pt_regs(task); 160 gdb_regs[0] = thread_regs->r00; 161 } 162 163 /** 164 * kgdb_arch_handle_exception - Handle architecture specific GDB packets. 165 * @vector: The error vector of the exception that happened. 166 * @signo: The signal number of the exception that happened. 167 * @err_code: The error code of the exception that happened. 168 * @remcom_in_buffer: The buffer of the packet we have read. 169 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. 170 * @regs: The &struct pt_regs of the current process. 171 * 172 * This function MUST handle the 'c' and 's' command packets, 173 * as well packets to set / remove a hardware breakpoint, if used. 174 * If there are additional packets which the hardware needs to handle, 175 * they are handled here. The code should return -1 if it wants to 176 * process more packets, and a %0 or %1 if it wants to exit from the 177 * kgdb callback. 178 * 179 * Not yet working. 180 */ 181 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 182 char *remcom_in_buffer, char *remcom_out_buffer, 183 struct pt_regs *linux_regs) 184 { 185 switch (remcom_in_buffer[0]) { 186 case 's': 187 case 'c': 188 return 0; 189 } 190 /* Stay in the debugger. */ 191 return -1; 192 } 193 194 static int __kgdb_notify(struct die_args *args, unsigned long cmd) 195 { 196 /* cpu roundup */ 197 if (atomic_read(&kgdb_active) != -1) { 198 kgdb_nmicallback(smp_processor_id(), args->regs); 199 return NOTIFY_STOP; 200 } 201 202 if (user_mode(args->regs)) 203 return NOTIFY_DONE; 204 205 if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err, 206 args->regs)) 207 return NOTIFY_DONE; 208 209 return NOTIFY_STOP; 210 } 211 212 static int 213 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) 214 { 215 unsigned long flags; 216 int ret; 217 218 local_irq_save(flags); 219 ret = __kgdb_notify(ptr, cmd); 220 local_irq_restore(flags); 221 222 return ret; 223 } 224 225 static struct notifier_block kgdb_notifier = { 226 .notifier_call = kgdb_notify, 227 228 /* 229 * Lowest-prio notifier priority, we want to be notified last: 230 */ 231 .priority = -INT_MAX, 232 }; 233 234 /** 235 * kgdb_arch_init - Perform any architecture specific initalization. 236 * 237 * This function will handle the initalization of any architecture 238 * specific callbacks. 239 */ 240 int kgdb_arch_init(void) 241 { 242 return register_die_notifier(&kgdb_notifier); 243 } 244 245 /** 246 * kgdb_arch_exit - Perform any architecture specific uninitalization. 247 * 248 * This function will handle the uninitalization of any architecture 249 * specific callbacks, for dynamic registration and unregistration. 250 */ 251 void kgdb_arch_exit(void) 252 { 253 unregister_die_notifier(&kgdb_notifier); 254 } 255