1b9177f749
This will be used for implementing the xtensa select_one system call. Choose "poll" over "select" so that we can reuse Glib's g_poll constants and to avoid struct timeval. Reviewed-by: Luc Michel <lmichel@kalray.eu> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
144 lines
3.7 KiB
C
144 lines
3.7 KiB
C
/*
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* Semihosting Console Support
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*
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* Copyright (c) 2015 Imagination Technologies
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* Copyright (c) 2019 Linaro Ltd
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*
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* This provides support for outputting to a semihosting console.
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*
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* While most semihosting implementations support reading and writing
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* to arbitrary file descriptors we treat the console as something
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* specifically for debugging interaction. This means messages can be
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* re-directed to gdb (if currently being used to debug) or even
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* re-directed elsewhere.
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "qemu/osdep.h"
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#include "semihosting/semihost.h"
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#include "semihosting/console.h"
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#include "exec/gdbstub.h"
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#include "exec/exec-all.h"
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#include "qemu/log.h"
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#include "chardev/char.h"
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#include "chardev/char-fe.h"
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#include "qemu/main-loop.h"
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#include "qapi/error.h"
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#include "qemu/fifo8.h"
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/* Access to this structure is protected by the BQL */
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typedef struct SemihostingConsole {
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CharBackend backend;
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Chardev *chr;
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GSList *sleeping_cpus;
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bool got;
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Fifo8 fifo;
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} SemihostingConsole;
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static SemihostingConsole console;
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int qemu_semihosting_log_out(const char *s, int len)
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{
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if (console.chr) {
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return qemu_chr_write_all(console.chr, (uint8_t *) s, len);
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} else {
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return write(STDERR_FILENO, s, len);
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}
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}
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#define FIFO_SIZE 1024
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static int console_can_read(void *opaque)
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{
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SemihostingConsole *c = opaque;
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int ret;
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g_assert(qemu_mutex_iothread_locked());
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ret = (int) fifo8_num_free(&c->fifo);
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return ret;
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}
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static void console_wake_up(gpointer data, gpointer user_data)
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{
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CPUState *cs = (CPUState *) data;
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/* cpu_handle_halt won't know we have work so just unbung here */
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cs->halted = 0;
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qemu_cpu_kick(cs);
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}
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static void console_read(void *opaque, const uint8_t *buf, int size)
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{
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SemihostingConsole *c = opaque;
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g_assert(qemu_mutex_iothread_locked());
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while (size-- && !fifo8_is_full(&c->fifo)) {
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fifo8_push(&c->fifo, *buf++);
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}
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g_slist_foreach(c->sleeping_cpus, console_wake_up, NULL);
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c->sleeping_cpus = NULL;
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}
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bool qemu_semihosting_console_ready(void)
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{
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SemihostingConsole *c = &console;
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g_assert(qemu_mutex_iothread_locked());
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return !fifo8_is_empty(&c->fifo);
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}
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void qemu_semihosting_console_block_until_ready(CPUState *cs)
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{
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SemihostingConsole *c = &console;
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g_assert(qemu_mutex_iothread_locked());
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/* Block if the fifo is completely empty. */
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if (fifo8_is_empty(&c->fifo)) {
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c->sleeping_cpus = g_slist_prepend(c->sleeping_cpus, cs);
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cs->halted = 1;
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cs->exception_index = EXCP_HALTED;
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cpu_loop_exit(cs);
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/* never returns */
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}
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}
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int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
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{
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SemihostingConsole *c = &console;
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int ret = 0;
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qemu_semihosting_console_block_until_ready(cs);
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/* Read until buffer full or fifo exhausted. */
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do {
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*(char *)(buf + ret) = fifo8_pop(&c->fifo);
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ret++;
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} while (ret < len && !fifo8_is_empty(&c->fifo));
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return ret;
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}
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int qemu_semihosting_console_write(void *buf, int len)
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{
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if (console.chr) {
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return qemu_chr_write_all(console.chr, (uint8_t *)buf, len);
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} else {
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return fwrite(buf, 1, len, stderr);
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}
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}
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void qemu_semihosting_console_init(Chardev *chr)
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{
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console.chr = chr;
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if (chr) {
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fifo8_create(&console.fifo, FIFO_SIZE);
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qemu_chr_fe_init(&console.backend, chr, &error_abort);
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qemu_chr_fe_set_handlers(&console.backend,
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console_can_read,
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console_read,
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NULL, NULL, &console,
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NULL, true);
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}
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qemu_semihosting_guestfd_init();
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}
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