arch/nios2/kernel/kgdb.c

   1 /*
   2  * Nios2 KGDB support
   3  *
   4  * Copyright (C) 2015 Altera Corporation
   5  * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
   6  *
   7  * Based on the code posted by Kazuyasu on the Altera Forum at:
   8  * http://www.alteraforum.com/forum/showpost.php?p=77003&postcount=20
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  */
  24 #include <linux/ptrace.h>
  25 #include <linux/kgdb.h>
  26 #include <linux/kdebug.h>
  27 #include <linux/io.h>
  28
  29 static int wait_for_remote_debugger;
  30
  31 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
  32 {
  33         { "zero", GDB_SIZEOF_REG, -1 },
  34         { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, r1) },
  35         { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r2) },
  36         { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r3) },
  37         { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r4) },
  38         { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r5) },
  39         { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r6) },
  40         { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r7) },
  41         { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r8) },
  42         { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r9) },
  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, -1 },
  50         { "r17", GDB_SIZEOF_REG, -1 },
  51         { "r18", GDB_SIZEOF_REG, -1 },
  52         { "r19", GDB_SIZEOF_REG, -1 },
  53         { "r20", GDB_SIZEOF_REG, -1 },
  54         { "r21", GDB_SIZEOF_REG, -1 },
  55         { "r22", GDB_SIZEOF_REG, -1 },
  56         { "r23", GDB_SIZEOF_REG, -1 },
  57         { "et", GDB_SIZEOF_REG, -1 },
  58         { "bt", GDB_SIZEOF_REG, -1 },
  59         { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp) },
  60         { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, sp) },
  61         { "fp", GDB_SIZEOF_REG, offsetof(struct pt_regs, fp) },
  62         { "ea", GDB_SIZEOF_REG, -1 },
  63         { "ba", GDB_SIZEOF_REG, -1 },
  64         { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, ra) },
  65         { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, ea) },
  66         { "status", GDB_SIZEOF_REG, -1 },
  67         { "estatus", GDB_SIZEOF_REG, offsetof(struct pt_regs, estatus) },
  68         { "bstatus", GDB_SIZEOF_REG, -1 },
  69         { "ienable", GDB_SIZEOF_REG, -1 },
  70         { "ipending", GDB_SIZEOF_REG, -1},
  71         { "cpuid", GDB_SIZEOF_REG, -1 },
  72         { "ctl6", GDB_SIZEOF_REG, -1 },
  73         { "exception", GDB_SIZEOF_REG, -1 },
  74         { "pteaddr", GDB_SIZEOF_REG, -1 },
  75         { "tlbacc", GDB_SIZEOF_REG, -1 },
  76         { "tlbmisc", GDB_SIZEOF_REG, -1 },
  77         { "eccinj", GDB_SIZEOF_REG, -1 },
  78         { "badaddr", GDB_SIZEOF_REG, -1 },
  79         { "config", GDB_SIZEOF_REG, -1 },
  80         { "mpubase", GDB_SIZEOF_REG, -1 },
  81         { "mpuacc", GDB_SIZEOF_REG, -1 },
  82 };
  83
  84 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  85 {
  86         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  87                 return NULL;
  88
  89         if (dbg_reg_def[regno].offset != -1)
  90                 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
  91                        dbg_reg_def[regno].size);
  92         else
  93                 memset(mem, 0, dbg_reg_def[regno].size);
  94
  95         return dbg_reg_def[regno].name;
  96 }
  97
  98 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
  99 {
 100         if (regno >= DBG_MAX_REG_NUM || regno < 0)
 101                 return -EINVAL;
 102
 103         if (dbg_reg_def[regno].offset != -1)
 104                 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
 105                        dbg_reg_def[regno].size);
 106
 107         return 0;
 108 }
 109
 110 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 111 {
 112         memset((char *)gdb_regs, 0, NUMREGBYTES);
 113         gdb_regs[GDB_SP] = p->thread.kregs->sp;
 114         gdb_regs[GDB_PC] = p->thread.kregs->ea;
 115 }
 116
 117 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 118 {
 119         regs->ea = pc;
 120 }
 121
 122 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 123                                 char *remcom_in_buffer, char *remcom_out_buffer,
 124                                 struct pt_regs *regs)
 125 {
 126         char *ptr;
 127         unsigned long addr;
 128
 129         switch (remcom_in_buffer[0]) {
 130         case 's':
 131         case 'c':
 132                 /* handle the optional parameters */
 133                 ptr = &remcom_in_buffer[1];
 134                 if (kgdb_hex2long(&ptr, &addr))
 135                         regs->ea = addr;
 136
 137                 return 0;
 138         }
 139
 140         return -1; /* this means that we do not want to exit from the handler */
 141 }
 142
 143 asmlinkage void kgdb_breakpoint_c(struct pt_regs *regs)
 144 {
 145         /*
 146          * The breakpoint entry code has moved the PC on by 4 bytes, so we must
 147          * move it back.  This could be done on the host but we do it here
 148          */
 149         if (!wait_for_remote_debugger)
 150                 regs->ea -= 4;
 151         else    /* pass the first trap 30 code */
 152                 wait_for_remote_debugger = 0;
 153
 154         kgdb_handle_exception(30, SIGTRAP, 0, regs);
 155 }
 156
 157 int kgdb_arch_init(void)
 158 {
 159         wait_for_remote_debugger = 1;
 160         return 0;
 161 }
 162
 163 void kgdb_arch_exit(void)
 164 {
 165         /* Nothing to do */
 166 }
 167
 168 struct kgdb_arch arch_kgdb_ops = {
 169         /* Breakpoint instruction: trap 30 */
 170         .gdb_bpt_instr = { 0xba, 0x6f, 0x3b, 0x00 },
 171 };