LXR qemu/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
  26int 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 */
  41static 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
  61static 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
  69int 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
  84void 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}
 101