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/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 { "cs0", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs0)}, 74 { "cs1", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs1)}, 75 { "psp", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmpsp)}, 76 { "elr", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmel)}, 77 { "est", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmest)}, 78 { "badva", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmbadva)}, 79 { "restart_r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, restart_r0)}, 80 { "syscall_nr", GDB_SIZEOF_REG, offsetof(struct pt_regs, syscall_nr)}, 81 }; 82 83 struct kgdb_arch arch_kgdb_ops = { 84 /* trap0(#0xDB) 0x0cdb0054 */ 85 .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c}, 86 }; 87 88 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) 89 { 90 if (regno >= DBG_MAX_REG_NUM || regno < 0) 91 return NULL; 92 93 *((unsigned long *) mem) = *((unsigned long *) ((void *)regs + 94 dbg_reg_def[regno].offset)); 95 96 return dbg_reg_def[regno].name; 97 } 98 99 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) 100 { 101 if (regno >= DBG_MAX_REG_NUM || regno < 0) 102 return -EINVAL; 103 104 *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) = 105 *((unsigned long *) mem); 106 107 return 0; 108 } 109 110 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 111 { 112 instruction_pointer(regs) = pc; 113 } 114 115 #ifdef CONFIG_SMP 116 117 /** 118 * kgdb_roundup_cpus - Get other CPUs into a holding pattern 119 * @flags: Current IRQ state 120 * 121 * On SMP systems, we need to get the attention of the other CPUs 122 * and get them be in a known state. This should do what is needed 123 * to get the other CPUs to call kgdb_wait(). Note that on some arches, 124 * the NMI approach is not used for rounding up all the CPUs. For example, 125 * in case of MIPS, smp_call_function() is used to roundup CPUs. In 126 * this case, we have to make sure that interrupts are enabled before 127 * calling smp_call_function(). The argument to this function is 128 * the flags that will be used when restoring the interrupts. There is 129 * local_irq_save() call before kgdb_roundup_cpus(). 130 * 131 * On non-SMP systems, this is not called. 132 */ 133 134 static void hexagon_kgdb_nmi_hook(void *ignored) 135 { 136 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); 137 } 138 139 void kgdb_roundup_cpus(unsigned long flags) 140 { 141 local_irq_enable(); 142 smp_call_function(hexagon_kgdb_nmi_hook, NULL, 0); 143 local_irq_disable(); 144 } 145 #endif 146 147 148 /* Not yet working */ 149 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, 150 struct task_struct *task) 151 { 152 struct pt_regs *thread_regs; 153 154 if (task == NULL) 155 return; 156 157 /* Initialize to zero */ 158 memset(gdb_regs, 0, NUMREGBYTES); 159 160 /* Otherwise, we have only some registers from switch_to() */ 161 thread_regs = task_pt_regs(task); 162 gdb_regs[0] = thread_regs->r00; 163 } 164 165 /** 166 * kgdb_arch_handle_exception - Handle architecture specific GDB packets. 167 * @vector: The error vector of the exception that happened. 168 * @signo: The signal number of the exception that happened. 169 * @err_code: The error code of the exception that happened. 170 * @remcom_in_buffer: The buffer of the packet we have read. 171 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. 172 * @regs: The &struct pt_regs of the current process. 173 * 174 * This function MUST handle the 'c' and 's' command packets, 175 * as well packets to set / remove a hardware breakpoint, if used. 176 * If there are additional packets which the hardware needs to handle, 177 * they are handled here. The code should return -1 if it wants to 178 * process more packets, and a %0 or %1 if it wants to exit from the 179 * kgdb callback. 180 * 181 * Not yet working. 182 */ 183 int kgdb_arch_handle_exception(int vector, int signo, int err_code, 184 char *remcom_in_buffer, char *remcom_out_buffer, 185 struct pt_regs *linux_regs) 186 { 187 switch (remcom_in_buffer[0]) { 188 case 's': 189 case 'c': 190 return 0; 191 } 192 /* Stay in the debugger. */ 193 return -1; 194 } 195 196 static int __kgdb_notify(struct die_args *args, unsigned long cmd) 197 { 198 /* cpu roundup */ 199 if (atomic_read(&kgdb_active) != -1) { 200 kgdb_nmicallback(smp_processor_id(), args->regs); 201 return NOTIFY_STOP; 202 } 203 204 if (user_mode(args->regs)) 205 return NOTIFY_DONE; 206 207 if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err, 208 args->regs)) 209 return NOTIFY_DONE; 210 211 return NOTIFY_STOP; 212 } 213 214 static int 215 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) 216 { 217 unsigned long flags; 218 int ret; 219 220 local_irq_save(flags); 221 ret = __kgdb_notify(ptr, cmd); 222 local_irq_restore(flags); 223 224 return ret; 225 } 226 227 static struct notifier_block kgdb_notifier = { 228 .notifier_call = kgdb_notify, 229 230 /* 231 * Lowest-prio notifier priority, we want to be notified last: 232 */ 233 .priority = -INT_MAX, 234 }; 235 236 /** 237 * kgdb_arch_init - Perform any architecture specific initalization. 238 * 239 * This function will handle the initalization of any architecture 240 * specific callbacks. 241 */ 242 int kgdb_arch_init(void) 243 { 244 return register_die_notifier(&kgdb_notifier); 245 } 246 247 /** 248 * kgdb_arch_exit - Perform any architecture specific uninitalization. 249 * 250 * This function will handle the uninitalization of any architecture 251 * specific callbacks, for dynamic registration and unregistration. 252 */ 253 void kgdb_arch_exit(void) 254 { 255 unregister_die_notifier(&kgdb_notifier); 256 } 257