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 "gdbstub/syscalls.h"
  27 #include "gdbstub/helpers.h"
  28 #include "semihosting/syscalls.h"
  29 #include "semihosting/softmmu-uaccess.h"
  30 #include "qemu/log.h"
  31
  32 #define HOSTED_EXIT  0
  33 #define HOSTED_INIT_SIM 1
  34 #define HOSTED_OPEN 2
  35 #define HOSTED_CLOSE 3
  36 #define HOSTED_READ 4
  37 #define HOSTED_WRITE 5
  38 #define HOSTED_LSEEK 6
  39 #define HOSTED_RENAME 7
  40 #define HOSTED_UNLINK 8
  41 #define HOSTED_STAT 9
  42 #define HOSTED_FSTAT 10
  43 #define HOSTED_GETTIMEOFDAY 11
  44 #define HOSTED_ISATTY 12
  45 #define HOSTED_SYSTEM 13
  46
  47 static int host_to_gdb_errno(int err)
  48 {
  49 #define E(X)  case E##X: return GDB_E##X
  50     switch (err) {
  51     E(PERM);
  52     E(NOENT);
  53     E(INTR);
  54     E(BADF);
  55     E(ACCES);
  56     E(FAULT);
  57     E(BUSY);
  58     E(EXIST);
  59     E(NODEV);
  60     E(NOTDIR);
  61     E(ISDIR);
  62     E(INVAL);
  63     E(NFILE);
  64     E(MFILE);
  65     E(FBIG);
  66     E(NOSPC);
  67     E(SPIPE);
  68     E(ROFS);
  69     E(NAMETOOLONG);
  70     default:
  71         return GDB_EUNKNOWN;
  72     }
  73 #undef E
  74 }
  75
  76 static void nios2_semi_u32_cb(CPUState *cs, uint64_t ret, int err)
  77 {
  78     Nios2CPU *cpu = NIOS2_CPU(cs);
  79     CPUNios2State *env = &cpu->env;
  80     target_ulong args = env->regs[R_ARG1];
  81
  82     if (put_user_u32(ret, args) ||
  83         put_user_u32(host_to_gdb_errno(err), args + 4)) {
  84         /*
  85          * The nios2 semihosting ABI does not provide any way to report this
  86          * error to the guest, so the best we can do is log it in qemu.
  87          * It is always a guest error not to pass us a valid argument block.
  88          */
  89         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
  90                       "discarded because argument block not writable\n");
  91     }
  92 }
  93
  94 static void nios2_semi_u64_cb(CPUState *cs, uint64_t ret, int err)
  95 {
  96     Nios2CPU *cpu = NIOS2_CPU(cs);
  97     CPUNios2State *env = &cpu->env;
  98     target_ulong args = env->regs[R_ARG1];
  99
 100     if (put_user_u32(ret >> 32, args) ||
 101         put_user_u32(ret, args + 4) ||
 102         put_user_u32(host_to_gdb_errno(err), args + 8)) {
 103         /* No way to report this via nios2 semihosting ABI; just log it */
 104         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: return value "
 105                       "discarded because argument block not writable\n");
 106     }
 107 }
 108
 109 /*
 110  * Read the input value from the argument block; fail the semihosting
 111  * call if the memory read fails.
 112  */
 113 #define GET_ARG(n) do {                                 \
 114     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
 115         goto failed;                                    \
 116     }                                                   \
 117 } while (0)
 118
 119 #define GET_ARG64(n) do {                               \
 120     if (get_user_ual(arg ## n, args + (n) * 4)) {       \
 121         goto failed64;                                  \
 122     }                                                   \
 123 } while (0)
 124
 125 void do_nios2_semihosting(CPUNios2State *env)
 126 {
 127     CPUState *cs = env_cpu(env);
 128     int nr;
 129     uint32_t args;
 130     target_ulong arg0, arg1, arg2, arg3;
 131
 132     nr = env->regs[R_ARG0];
 133     args = env->regs[R_ARG1];
 134     switch (nr) {
 135     case HOSTED_EXIT:
 136         gdb_exit(env->regs[R_ARG0]);
 137         exit(env->regs[R_ARG0]);
 138
 139     case HOSTED_OPEN:
 140         GET_ARG(0);
 141         GET_ARG(1);
 142         GET_ARG(2);
 143         GET_ARG(3);
 144         semihost_sys_open(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
 145         break;
 146
 147     case HOSTED_CLOSE:
 148         GET_ARG(0);
 149         semihost_sys_close(cs, nios2_semi_u32_cb, arg0);
 150         break;
 151
 152     case HOSTED_READ:
 153         GET_ARG(0);
 154         GET_ARG(1);
 155         GET_ARG(2);
 156         semihost_sys_read(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
 157         break;
 158
 159     case HOSTED_WRITE:
 160         GET_ARG(0);
 161         GET_ARG(1);
 162         GET_ARG(2);
 163         semihost_sys_write(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
 164         break;
 165
 166     case HOSTED_LSEEK:
 167         GET_ARG64(0);
 168         GET_ARG64(1);
 169         GET_ARG64(2);
 170         GET_ARG64(3);
 171         semihost_sys_lseek(cs, nios2_semi_u64_cb, arg0,
 172                            deposit64(arg2, arg1, 32, 32), arg3);
 173         break;
 174
 175     case HOSTED_RENAME:
 176         GET_ARG(0);
 177         GET_ARG(1);
 178         GET_ARG(2);
 179         GET_ARG(3);
 180         semihost_sys_rename(cs, nios2_semi_u32_cb, arg0, arg1, arg2, arg3);
 181         break;
 182
 183     case HOSTED_UNLINK:
 184         GET_ARG(0);
 185         GET_ARG(1);
 186         semihost_sys_remove(cs, nios2_semi_u32_cb, arg0, arg1);
 187         break;
 188
 189     case HOSTED_STAT:
 190         GET_ARG(0);
 191         GET_ARG(1);
 192         GET_ARG(2);
 193         semihost_sys_stat(cs, nios2_semi_u32_cb, arg0, arg1, arg2);
 194         break;
 195
 196     case HOSTED_FSTAT:
 197         GET_ARG(0);
 198         GET_ARG(1);
 199         semihost_sys_fstat(cs, nios2_semi_u32_cb, arg0, arg1);
 200         break;
 201
 202     case HOSTED_GETTIMEOFDAY:
 203         GET_ARG(0);
 204         GET_ARG(1);
 205         semihost_sys_gettimeofday(cs, nios2_semi_u32_cb, arg0, arg1);
 206         break;
 207
 208     case HOSTED_ISATTY:
 209         GET_ARG(0);
 210         semihost_sys_isatty(cs, nios2_semi_u32_cb, arg0);
 211         break;
 212
 213     case HOSTED_SYSTEM:
 214         GET_ARG(0);
 215         GET_ARG(1);
 216         semihost_sys_system(cs, nios2_semi_u32_cb, arg0, arg1);
 217         break;
 218
 219     default:
 220         qemu_log_mask(LOG_GUEST_ERROR, "nios2-semihosting: unsupported "
 221                       "semihosting syscall %d\n", nr);
 222         nios2_semi_u32_cb(cs, -1, ENOSYS);
 223         break;
 224
 225     failed:
 226         nios2_semi_u32_cb(cs, -1, EFAULT);
 227         break;
 228     failed64:
 229         nios2_semi_u64_cb(cs, -1, EFAULT);
 230         break;
 231     }
 232 }