hw/semihosting/console.c

   1 /*
   2  * Semihosting Console Support
   3  *
   4  * Copyright (c) 2015 Imagination Technologies
   5  * Copyright (c) 2019 Linaro Ltd
   6  *
   7  * This provides support for outputting to a semihosting console.
   8  *
   9  * While most semihosting implementations support reading and writing
  10  * to arbitrary file descriptors we treat the console as something
  11  * specifically for debugging interaction. This means messages can be
  12  * re-directed to gdb (if currently being used to debug) or even
  13  * re-directed elsewhere.
  14  *
  15  * SPDX-License-Identifier: GPL-2.0-or-later
  16  */
  17
  18 #include "qemu/osdep.h"
  19 #include "cpu.h"
  20 #include "hw/semihosting/semihost.h"
  21 #include "hw/semihosting/console.h"
  22 #include "exec/gdbstub.h"
  23 #include "qemu/log.h"
  24 #include "chardev/char.h"
  25
  26 int qemu_semihosting_log_out(const char *s, int len)
  27 {
  28     Chardev *chardev = semihosting_get_chardev();
  29     if (chardev) {
  30         return qemu_chr_write_all(chardev, (uint8_t *) s, len);
  31     } else {
  32         return write(STDERR_FILENO, s, len);
  33     }
  34 }
  35
  36 /*
  37  * A re-implementation of lock_user_string that we can use locally
  38  * instead of relying on softmmu-semi. Hopefully we can deprecate that
  39  * in time. Copy string until we find a 0 or address error.
  40  */
  41 static GString *copy_user_string(CPUArchState *env, target_ulong addr)
  42 {
  43     CPUState *cpu = env_cpu(env);
  44     GString *s = g_string_sized_new(128);
  45     uint8_t c;
  46
  47     do {
  48         if (cpu_memory_rw_debug(cpu, addr++, &c, 1, 0) == 0) {
  49             s = g_string_append_c(s, c);
  50         } else {
  51             qemu_log_mask(LOG_GUEST_ERROR,
  52                           "%s: passed inaccessible address " TARGET_FMT_lx,
  53                           __func__, addr);
  54             break;
  55         }
  56     } while (c!=0);
  57
  58     return s;
  59 }
  60
  61 static void semihosting_cb(CPUState *cs, target_ulong ret, target_ulong err)
  62 {
  63     if (ret == (target_ulong) -1) {
  64         qemu_log("%s: gdb console output failed ("TARGET_FMT_ld")",
  65                  __func__, err);
  66     }
  67 }
  68
  69 int qemu_semihosting_console_outs(CPUArchState *env, target_ulong addr)
  70 {
  71     GString *s = copy_user_string(env, addr);
  72     int out = s->len;
  73
  74     if (use_gdb_syscalls()) {
  75         gdb_do_syscall(semihosting_cb, "write,2,%x,%x", addr, s->len);
  76     } else {
  77         out = qemu_semihosting_log_out(s->str, s->len);
  78     }
  79
  80     g_string_free(s, true);
  81     return out;
  82 }
  83
  84 void qemu_semihosting_console_outc(CPUArchState *env, target_ulong addr)
  85 {
  86     CPUState *cpu = env_cpu(env);
  87     uint8_t c;
  88
  89     if (cpu_memory_rw_debug(cpu, addr, &c, 1, 0) == 0) {
  90         if (use_gdb_syscalls()) {
  91             gdb_do_syscall(semihosting_cb, "write,2,%x,%x", addr, 1);
  92         } else {
  93             qemu_semihosting_log_out((const char *) &c, 1);
  94         }
  95     } else {
  96         qemu_log_mask(LOG_GUEST_ERROR,
  97                       "%s: passed inaccessible address " TARGET_FMT_lx,
  98                       __func__, addr);
  99     }
 100 }