target/nios2/nios2-semi.c

   1 /*
   2  *  Nios II Semihosting syscall interface.
   3  *  This code is derived from m68k-semi.c.
   4  *  The semihosting protocol implemented here is described in the
   5  *  libgloss sources:
   6  *  https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=blob;f=libgloss/nios2/nios2-semi.txt;hb=HEAD
   7  *
   8  *  Copyright (c) 2017-2019 Mentor Graphics
   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 "qemu/osdep.h"
  25 #include "cpu.h"
  26 #include "exec/gdbstub.h"
  27 #include "semihosting/syscalls.h"
  28 #include "semihosting/softmmu-uaccess.h"
  29 #include "qemu/log.h"
  30
  31 #define HOSTED_EXIT  0
  32 #define HOSTED_INIT_SIM 1
  33 #define HOSTED_OPEN 2
  34 #define HOSTED_CLOSE 3
  35 #define HOSTED_READ 4
  36 #define HOSTED_WRITE 5
  37 #define HOSTED_LSEEK 6
  38 #define HOSTED_RENAME 7
  39 #define HOSTED_UNLINK 8
  40 #define HOSTED_STAT 9
  41 #define HOSTED_FSTAT 10
  42 #define HOSTED_GETTIMEOFDAY 11
  43 #define HOSTED_ISATTY 12
  44 #define HOSTED_SYSTEM 13
  45
  46 static int host_to_gdb_errno(int err)
  47 {
  48 #define E(X)  case E##X: return GDB_E##X
  49     switch (err) {
  50     E(PERM);
  51     E(NOENT);
  52     E(INTR);
  53     E(BADF);
  54     E(ACCES);
  55     E(FAULT);
  56     E(BUSY);
  57     E(EXIST);
  58     E(NODEV);
  59     E(NOTDIR);
  60     E(ISDIR);
  61     E(INVAL);
  62     E(NFILE);
  63     E(MFILE);
  64     E(FBIG);
  65     E(NOSPC);
  66     E(SPIPE);
  67     E(ROFS);
  68     E(NAMETOOLONG);
  69     default:
  70         return GDB_EUNKNOWN;
  71     }
  72 #undef E
  73 }
  74
  75 static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
  76 {
  77     Nios2CPU *cpu = NIOS2_CPU(cs);
  78     CPUNios2State *env = &cpu->env;
  79     target_ulong args = env->regs[R_ARG1];
  80
  81     if (put_user_u32(ret, args) ||
  82         put_user_u32(host_to_gdb_errno(err), args + 4)) {
  83         /*
  84          * The nios2 semihosting ABI does not provide any way to report this
  85          * error to the guest, so the best we can do is log it in qemu.
  86          * It is always a guest error not to pass us a valid argument block.
  87          */
  88         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
  89                       "discarded because argument block not writable\n");
  90     }
  91 }
  92
  93 static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
  94 {
  95     Nios2CPU *cpu = NIOS2_CPU(cs);
  96     CPUNios2State *env = &cpu->env;
  97     target_ulong args = env->regs[R_ARG1];
  98
  99     if (put_user_u32(ret >> 32, args) ||
 100         put_user_u32(ret, args + 4) ||
 101         put_user_u32(host_to_gdb_errno(err), args + 8)) {
 102         /* No way to report this via nios2 semihosting ABI; just log it */
 103         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
 104                       "discarded because argument block not writable\n");
 105     }
 106 }
 107
 108 /*
 109  * Read the input value from the argument block; fail the semihosting
 110  * call if the memory read fails.
 111  */
 112 #define GET_ARG(n) do {                                 \
 113     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
 114         goto failed;                                    \
 115     }                                                   \
 116 } while (0)
 117
 118 #define GET_ARG64(n) do {                               \
 119     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
 120         goto failed64;                                  \
 121     }                                                   \
 122 } while (0)
 123
 124 void do_nios2_semihosting(CPUNios2State *env)
 125 {
 126     CPUState *cs = env_cpu(env);
 127     int nr;
 128     uint32_t args;
 129     target_ulong arg0, arg1, arg2, arg3;
 130
 131     nr = env->regs[R_ARG0];
 132     args = env->regs[R_ARG1];
 133     switch (nr) {
 134     case HOSTED_EXIT:
 135         gdb_exit(env->regs[R_ARG0]);
 136         exit(env->regs[R_ARG0]);
 137
 138     case HOSTED_OPEN:
 139         GET_ARG(0);
 140         GET_ARG(1);
 141         GET_ARG(2);
 142         GET_ARG(3);
 143         semihost_sys_open(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
 144         break;
 145
 146     case HOSTED_CLOSE:
 147         GET_ARG(0);
 148         semihost_sys_close(cs, nios2_semi_u32_cb, arg0);
 149         break;
 150
 151     case HOSTED_READ:
 152         GET_ARG(0);
 153         GET_ARG(1);
 154         GET_ARG(2);
 155         semihost_sys_read(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
 156         break;
 157
 158     case HOSTED_WRITE:
 159         GET_ARG(0);
 160         GET_ARG(1);
 161         GET_ARG(2);
 162         semihost_sys_write(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
 163         break;
 164
 165     case HOSTED_LSEEK:
 166         GET_ARG64(0);
 167         GET_ARG64(1);
 168         GET_ARG64(2);
 169         GET_ARG64(3);
 170         semihost_sys_lseek(cs, nios2_semi_u64_cb, arg0,
 171                            deposit64(arg2, arg1, 32, 32), arg3);
 172         break;
 173
 174     case HOSTED_RENAME:
 175         GET_ARG(0);
 176         GET_ARG(1);
 177         GET_ARG(2);
 178         GET_ARG(3);
 179         semihost_sys_rename(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
 180         break;
 181
 182     case HOSTED_UNLINK:
 183         GET_ARG(0);
 184         GET_ARG(1);
 185         semihost_sys_remove(cs, nios2_semi_u32_cb, arg0, arg1);
 186         break;
 187
 188     case HOSTED_STAT:
 189         GET_ARG(0);
 190         GET_ARG(1);
 191         GET_ARG(2);
 192         semihost_sys_stat(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
 193         break;
 194
 195     case HOSTED_FSTAT:
 196         GET_ARG(0);
 197         GET_ARG(1);
 198         semihost_sys_fstat(cs, nios2_semi_u32_cb, arg0, arg1);
 199         break;
 200
 201     case HOSTED_GETTIMEOFDAY:
 202         GET_ARG(0);
 203         GET_ARG(1);
 204         semihost_sys_gettimeofday(cs, nios2_semi_u32_cb, arg0, arg1);
 205         break;
 206
 207     case HOSTED_ISATTY:
 208         GET_ARG(0);
 209         semihost_sys_isatty(cs, nios2_semi_u32_cb, arg0);
 210         break;
 211
 212     case HOSTED_SYSTEM:
 213         GET_ARG(0);
 214         GET_ARG(1);
 215         semihost_sys_system(cs, nios2_semi_u32_cb, arg0, arg1);
 216         break;
 217
 218     default:
 219         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
 220                       "semihosting syscall %d\n", nr);
 221         nios2_semi_u32_cb(cs, -1, ENOSYS);
 222         break;
 223
 224     failed:
 225         nios2_semi_u32_cb(cs, -1, EFAULT);
 226         break;
 227     failed64:
 228         nios2_semi_u64_cb(cs, -1, EFAULT);
 229         break;
 230     }
 231 }