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/*
* Semihosting Console Support
*
* Copyright (c) 2015 Imagination Technologies
* Copyright (c) 2019 Linaro Ltd
*
* This provides support for outputting to a semihosting console.
*
* While most semihosting implementations support reading and writing
* to arbitrary file descriptors we treat the console as something
* specifically for debugging interaction. This means messages can be
* re-directed to gdb (if currently being used to debug) or even
* re-directed elsewhere.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "semihosting/semihost.h"
#include "semihosting/console.h"
#include "exec/cpu-common.h"
#include "exec/gdbstub.h"
#include "qemu/log.h"
#include "chardev/char.h"
#include "chardev/char-fe.h"
#include "qemu/main-loop.h"
#include "qapi/error.h"
#include "qemu/fifo8.h"
#include "hw/core/cpu.h"
/* Access to this structure is protected by the BQL */
typedef struct SemihostingConsole {
CharBackend backend;
Chardev *chr;
GSList *sleeping_cpus;
bool got;
Fifo8 fifo;
} SemihostingConsole;
static SemihostingConsole console;
#define FIFO_SIZE 1024
static int console_can_read(void *opaque)
{
SemihostingConsole *c = opaque;
g_assert(bql_locked());
return (int)fifo8_num_free(&c->fifo);
}
static void console_wake_up(gpointer data, gpointer user_data)
{
CPUState *cs = (CPUState *) data;
/* cpu_handle_halt won't know we have work so just unbung here */
cs->halted = 0;
qemu_cpu_kick(cs);
}
static void console_read(void *opaque, const uint8_t *buf, int size)
{
SemihostingConsole *c = opaque;
g_assert(bql_locked());
while (size-- && !fifo8_is_full(&c->fifo)) {
fifo8_push(&c->fifo, *buf++);
}
g_slist_foreach(c->sleeping_cpus, console_wake_up, NULL);
c->sleeping_cpus = NULL;
}
bool qemu_semihosting_console_ready(void)
{
SemihostingConsole *c = &console;
g_assert(bql_locked());
return !fifo8_is_empty(&c->fifo);
}
void qemu_semihosting_console_block_until_ready(CPUState *cs)
{
SemihostingConsole *c = &console;
g_assert(bql_locked());
/* Block if the fifo is completely empty. */
if (fifo8_is_empty(&c->fifo)) {
c->sleeping_cpus = g_slist_prepend(c->sleeping_cpus, cs);
cs->halted = 1;
cs->exception_index = EXCP_HALTED;
cpu_loop_exit(cs);
/* never returns */
}
}
int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
{
SemihostingConsole *c = &console;
int ret = 0;
qemu_semihosting_console_block_until_ready(cs);
/* Read until buffer full or fifo exhausted. */
do {
*(char *)(buf + ret) = fifo8_pop(&c->fifo);
ret++;
} while (ret < len && !fifo8_is_empty(&c->fifo));
return ret;
}
int qemu_semihosting_console_write(void *buf, int len)
{
if (console.chr) {
int r = qemu_chr_write_all(console.chr, (uint8_t *)buf, len);
return r < 0 ? 0 : r;
} else {
return fwrite(buf, 1, len, stderr);
}
}
void qemu_semihosting_console_init(Chardev *chr)
{
console.chr = chr;
if (chr) {
fifo8_create(&console.fifo, FIFO_SIZE);
qemu_chr_fe_init(&console.backend, chr, &error_abort);
qemu_chr_fe_set_handlers(&console.backend,
console_can_read,
console_read,
NULL, NULL, &console,
NULL, true);
}
qemu_semihosting_guestfd_init();
}
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