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