target/riscv/gdbstub.c

   1 /*
   2  * RISC-V GDB Server Stub
   3  *
   4  * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2 or later, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "qemu/osdep.h"
  20 #include "qemu-common.h"
  21 #include "exec/gdbstub.h"
  22 #include "cpu.h"
  23
  24 int riscv_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
  25 {
  26     RISCVCPU *cpu = RISCV_CPU(cs);
  27     CPURISCVState *env = &cpu->env;
  28
  29     if (n < 32) {
  30         return gdb_get_regl(mem_buf, env->gpr[n]);
  31     } else if (n == 32) {
  32         return gdb_get_regl(mem_buf, env->pc);
  33     } else if (n < 65) {
  34         return gdb_get_reg64(mem_buf, env->fpr[n - 33]);
  35     } else if (n < 4096 + 65) {
  36         target_ulong val = 0;
  37         if (riscv_csrrw(env, n - 65, &val, 0, 0) == 0) {
  38             return gdb_get_regl(mem_buf, val);
  39         }
  40     }
  41     return 0;
  42 }
  43
  44 int riscv_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
  45 {
  46     RISCVCPU *cpu = RISCV_CPU(cs);
  47     CPURISCVState *env = &cpu->env;
  48
  49     if (n == 0) {
  50         /* discard writes to x0 */
  51         return sizeof(target_ulong);
  52     } else if (n < 32) {
  53         env->gpr[n] = ldtul_p(mem_buf);
  54         return sizeof(target_ulong);
  55     } else if (n == 32) {
  56         env->pc = ldtul_p(mem_buf);
  57         return sizeof(target_ulong);
  58     } else if (n < 65) {
  59         env->fpr[n - 33] = ldq_p(mem_buf); /* always 64-bit */
  60         return sizeof(uint64_t);
  61     } else if (n < 4096 + 65) {
  62         target_ulong val = ldtul_p(mem_buf);
  63         if (riscv_csrrw(env, n - 65, NULL, val, -1) == 0) {
  64             return sizeof(target_ulong);
  65         }
  66     }
  67     return 0;
  68 }