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 } 259