/* * Copyright (c) 2015 Julien Grall * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD: stable/11/sys/dev/xen/console/xen_console.c 362331 2020-06-18 15:44:40Z royger $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "opt_ddb.h" #include "opt_printf.h" #ifdef DDB #include #endif static char driver_name[] = "xc"; struct xencons_priv; typedef void xencons_early_init_t(struct xencons_priv *cons); typedef int xencons_init_t(device_t dev, struct tty *tp, driver_intr_t intr_handler); typedef int xencons_read_t(struct xencons_priv *cons, char *buffer, unsigned int size); typedef int xencons_write_t(struct xencons_priv *cons, const char *buffer, unsigned int size); struct xencons_ops { /* * Called by the low-level driver during early boot. * Only the minimal set up to get a console should be done here. */ xencons_early_init_t *early_init; /* Prepare the console to be fully use */ xencons_init_t *init; /* Read/write helpers */ xencons_read_t *read; xencons_write_t *write; }; struct xencons_priv { /* Mutex to protect the shared ring and the internal buffers */ struct mtx mtx; /* Interrupt handler used for notify the backend */ xen_intr_handle_t intr_handle; /* KDB internal state */ #ifdef KDB int altbrk; #endif /* Status of the tty */ bool opened; /* Callout used when the write buffer is full */ struct callout callout; /* Internal buffers must be used with mtx locked */ #define WBUF_SIZE 4096 #define WBUF_MASK(_i) ((_i)&(WBUF_SIZE-1)) char wbuf[WBUF_SIZE]; unsigned int wc, wp; /* Consumer/producer wbuf */ #define RBUF_SIZE 1024 #define RBUF_MASK(_i) ((_i)&(RBUF_SIZE-1)) char rbuf[RBUF_SIZE]; unsigned int rc, rp; /* Consumer/producer rbuf */ /* Pointer to the console operations */ const struct xencons_ops *ops; /* * Ring specific fields * XXX: make an union? */ /* Event channel number for early notification (PV only) */ uint32_t evtchn; /* Console shared page */ struct xencons_interface *intf; }; /* * Data for the main console * Necessary to support low-level console driver */ static struct xencons_priv main_cons; #define XC_POLLTIME (hz/10) /* * Virtual address of the shared console page (only for PV guest) * TODO: Introduce a function to set it */ char *console_page; /*----------------------------- Debug function ------------------------------*/ struct putchar_arg { char *buf; size_t size; size_t n_next; }; static void putchar(int c, void *arg) { struct putchar_arg *pca; pca = (struct putchar_arg *)arg; if (pca->buf == NULL) { /* * We have no buffer, output directly to the * console char by char. */ HYPERVISOR_console_write((char *)&c, 1); } else { pca->buf[pca->n_next++] = c; if ((pca->size == pca->n_next) || (c = '\0')) { /* Flush the buffer */ HYPERVISOR_console_write(pca->buf, pca->n_next); pca->n_next = 0; } } } void xc_printf(const char *fmt, ...) { va_list ap; struct putchar_arg pca; #ifdef PRINTF_BUFR_SIZE char buf[PRINTF_BUFR_SIZE]; pca.buf = buf; pca.size = sizeof(buf); pca.n_next = 0; #else pca.buf = NULL; pca.size = 0; #endif KASSERT((xen_domain()), ("call to xc_printf from non Xen guest")); va_start(ap, fmt); kvprintf(fmt, putchar, &pca, 10, ap); va_end(ap); #ifdef PRINTF_BUFR_SIZE if (pca.n_next != 0) HYPERVISOR_console_write(buf, pca.n_next); #endif } /*---------------------- Helpers for the console lock -----------------------*/ /* * The lock is not used when the kernel is panicing as it will never recover * and we want to output no matter what it costs. */ static inline void xencons_lock(struct xencons_priv *cons) { if (panicstr == NULL) mtx_lock_spin(&cons->mtx); } static inline void xencons_unlock(struct xencons_priv *cons) { if (panicstr == NULL) mtx_unlock_spin(&cons->mtx); } #define xencons_lock_assert(cons) mtx_assert(&(cons)->mtx, MA_OWNED) /*------------------ Helpers for the hypervisor console ---------------------*/ static void xencons_early_init_hypervisor(struct xencons_priv *cons) { /* * Nothing to setup for the low-level console when using * the hypervisor console. */ } static int xencons_init_hypervisor(device_t dev, struct tty *tp, driver_intr_t intr_handler) { struct xencons_priv *cons; int err; cons = tty_softc(tp); err = xen_intr_bind_virq(dev, VIRQ_CONSOLE, 0, NULL, intr_handler, tp, INTR_TYPE_TTY | INTR_MPSAFE, &cons->intr_handle); if (err != 0) device_printf(dev, "Can't register console interrupt\n"); return (err); } static int xencons_write_hypervisor(struct xencons_priv *cons, const char *buffer, unsigned int size) { HYPERVISOR_console_io(CONSOLEIO_write, size, buffer); return (size); } static int xencons_read_hypervisor(struct xencons_priv *cons, char *buffer, unsigned int size) { xencons_lock_assert(cons); return (HYPERVISOR_console_io(CONSOLEIO_read, size, buffer)); } static const struct xencons_ops xencons_hypervisor_ops = { .early_init = xencons_early_init_hypervisor, .init = xencons_init_hypervisor, .read = xencons_read_hypervisor, .write = xencons_write_hypervisor, }; /*------------------ Helpers for the ring console ---------------------------*/ static void xencons_early_init_ring(struct xencons_priv *cons) { /* The shared page for PV is already mapped by the boot code */ cons->intf = (struct xencons_interface *)console_page; cons->evtchn = HYPERVISOR_start_info->console.domU.evtchn; } static int xencons_init_ring(device_t dev, struct tty *tp, driver_intr_t intr_handler) { struct xencons_priv *cons; int err; cons = tty_softc(tp); if (cons->evtchn == 0) return (ENODEV); err = xen_intr_bind_local_port(dev, cons->evtchn, NULL, intr_handler, tp, INTR_TYPE_TTY | INTR_MPSAFE, &cons->intr_handle); if (err != 0) return (err); return (0); } static void xencons_notify_ring(struct xencons_priv *cons) { /* * The console may be used before the ring interrupt is properly * initialized. * If so, fallback to directly use the event channel hypercall. */ if (__predict_true(cons->intr_handle != NULL)) xen_intr_signal(cons->intr_handle); else { struct evtchn_send send = { .port = cons->evtchn }; HYPERVISOR_event_channel_op(EVTCHNOP_send, &send); } } static int xencons_write_ring(struct xencons_priv *cons, const char *buffer, unsigned int size) { struct xencons_interface *intf; XENCONS_RING_IDX wcons, wprod; int sent; intf = cons->intf; xencons_lock_assert(cons); wcons = intf->out_cons; wprod = intf->out_prod; mb(); KASSERT((wprod - wcons) <= sizeof(intf->out), ("console send ring inconsistent")); for (sent = 0; sent < size; sent++, wprod++) { if ((wprod - wcons) >= sizeof(intf->out)) break; intf->out[MASK_XENCONS_IDX(wprod, intf->out)] = buffer[sent]; } wmb(); intf->out_prod = wprod; xencons_notify_ring(cons); return (sent); } static int xencons_read_ring(struct xencons_priv *cons, char *buffer, unsigned int size) { struct xencons_interface *intf; XENCONS_RING_IDX rcons, rprod; unsigned int rsz; intf = cons->intf; xencons_lock_assert(cons); rcons = intf->in_cons; rprod = intf->in_prod; rmb(); for (rsz = 0; rsz < size; rsz++, rcons++) { if (rprod == rcons) break; buffer[rsz] = intf->in[MASK_XENCONS_IDX(rcons, intf->in)]; } wmb(); intf->in_cons = rcons; /* No need to notify the backend if nothing has been read */ if (rsz != 0) xencons_notify_ring(cons); return (rsz); } static const struct xencons_ops xencons_ring_ops = { .early_init = xencons_early_init_ring, .init = xencons_init_ring, .read = xencons_read_ring, .write = xencons_write_ring, }; /*------------------ Common implementation of the console -------------------*/ /* * Called by the low-level driver during early boot to initialize the * main console driver. * Only the minimal set up to get a console should be done here. */ static void xencons_early_init(void) { mtx_init(&main_cons.mtx, "XCONS LOCK", NULL, MTX_SPIN); if (xen_initial_domain()) main_cons.ops = &xencons_hypervisor_ops; else main_cons.ops = &xencons_ring_ops; main_cons.ops->early_init(&main_cons); } /* * Receive character from the console and put them in the internal buffer * XXX: Handle overflow of the internal buffer */ static void xencons_rx(struct xencons_priv *cons) { char buf[16]; int sz; xencons_lock(cons); while ((sz = cons->ops->read(cons, buf, sizeof(buf))) > 0) { int i; for (i = 0; i < sz; i++) cons->rbuf[RBUF_MASK(cons->rp++)] = buf[i]; } xencons_unlock(cons); } /* Return true if the write buffer is full */ static bool xencons_tx_full(struct xencons_priv *cons) { unsigned int used; xencons_lock(cons); used = cons->wp - cons->wc; xencons_unlock(cons); return (used >= WBUF_SIZE); } static void xencons_tx_flush(struct xencons_priv *cons, int force) { int sz; xencons_lock(cons); while (cons->wc != cons->wp) { int sent; sz = cons->wp - cons->wc; if (sz > (WBUF_SIZE - WBUF_MASK(cons->wc))) sz = WBUF_SIZE - WBUF_MASK(cons->wc); sent = cons->ops->write(cons, &cons->wbuf[WBUF_MASK(cons->wc)], sz); /* * The other end may not have been initialized. Ignore * the force. */ if (__predict_false(sent < 0)) break; /* * If force is set, spin until the console data is * flushed through the domain controller. */ if (sent == 0 && __predict_true(!force)) break; cons->wc += sent; } xencons_unlock(cons); } static bool xencons_putc(struct xencons_priv *cons, int c, bool force_flush) { xencons_lock(cons); if ((cons->wp - cons->wc) < WBUF_SIZE) cons->wbuf[WBUF_MASK(cons->wp++)] = c; xencons_unlock(cons); xencons_tx_flush(cons, force_flush); return (xencons_tx_full(cons)); } static int xencons_getc(struct xencons_priv *cons) { int ret; xencons_lock(cons); if (cons->rp != cons->rc) { /* We need to return only one char */ ret = (int)cons->rbuf[RBUF_MASK(cons->rc)]; cons->rc++; } else { ret = -1; } xencons_unlock(cons); return (ret); } static bool xencons_tx(struct tty *tp) { bool cons_full; char c; struct xencons_priv *cons; cons = tty_softc(tp); tty_lock_assert(tp, MA_OWNED); /* * Don't transmit any character if the buffer is full. Otherwise, * characters may be lost */ if (xencons_tx_full(cons)) return (false); cons_full = false; while (!cons_full && ttydisc_getc(tp, &c, 1) == 1) cons_full = xencons_putc(cons, c, false); return (!cons_full); } static void xencons_intr(void *arg) { struct tty *tp; struct xencons_priv *cons; int ret; tp = arg; cons = tty_softc(tp); /* * The input will be used by the low-level console when KDB is active */ if (kdb_active) return; /* * It's not necessary to retrieve input when the tty is not opened */ if (!cons->opened) return; xencons_rx(cons); tty_lock(tp); while ((ret = xencons_getc(cons)) != -1) { #ifdef KDB kdb_alt_break(ret, &cons->altbrk); #endif ttydisc_rint(tp, ret, 0); } ttydisc_rint_done(tp); tty_unlock(tp); /* Try to flush remaining characters if necessary */ xencons_tx_flush(cons, 0); } /* * Helpers to call while shutting down: * - Force flush all output */ static void xencons_shutdown(void *arg, int howto) { struct tty *tp; tp = arg; xencons_tx_flush(tty_softc(tp), 1); } /*---------------------- Low-level console driver ---------------------------*/ static void xencons_cnprobe(struct consdev *cp) { if (!xen_pv_domain()) return; cp->cn_pri = (boothowto & RB_SERIAL) ? CN_REMOTE : CN_NORMAL; sprintf(cp->cn_name, "%s0", driver_name); } static void xencons_cninit(struct consdev *cp) { xencons_early_init(); } static void xencons_cnterm(struct consdev *cp) { } static void xencons_cngrab(struct consdev *cp) { } static void xencons_cnungrab(struct consdev *cp) { } static int xencons_cngetc(struct consdev *dev) { xencons_rx(&main_cons); return (xencons_getc(&main_cons)); } static void xencons_cnputc(struct consdev *dev, int c) { /* * The low-level console is used by KDB and panic. We have to ensure * that any character sent will be seen by the backend. */ xencons_putc(&main_cons, c, true); } CONSOLE_DRIVER(xencons); /*----------------------------- TTY driver ---------------------------------*/ static int xencons_tty_open(struct tty *tp) { struct xencons_priv *cons; cons = tty_softc(tp); cons->opened = true; return (0); } static void xencons_tty_close(struct tty *tp) { struct xencons_priv *cons; cons = tty_softc(tp); cons->opened = false; } static void xencons_timeout(void *v) { struct tty *tp; struct xencons_priv *cons; tp = v; cons = tty_softc(tp); if (!xencons_tx(tp)) callout_reset(&cons->callout, XC_POLLTIME, xencons_timeout, tp); } static void xencons_tty_outwakeup(struct tty *tp) { struct xencons_priv *cons; cons = tty_softc(tp); callout_stop(&cons->callout); if (!xencons_tx(tp)) callout_reset(&cons->callout, XC_POLLTIME, xencons_timeout, tp); } static struct ttydevsw xencons_ttydevsw = { .tsw_flags = TF_NOPREFIX, .tsw_open = xencons_tty_open, .tsw_close = xencons_tty_close, .tsw_outwakeup = xencons_tty_outwakeup, }; /*------------------------ Main console driver ------------------------------*/ static void xencons_identify(driver_t *driver, device_t parent) { device_t child; #if defined(__arm__) || defined(__aarch64__) if (!xen_domain()) return; #else if (!xen_pv_domain()) return; #endif child = BUS_ADD_CHILD(parent, 0, driver_name, 0); } static int xencons_probe(device_t dev) { device_set_desc(dev, "Xen Console"); return (BUS_PROBE_NOWILDCARD); } static int xencons_attach(device_t dev) { struct tty *tp; /* * The main console is already allocated statically in order to * support low-level console */ struct xencons_priv *cons; int err; cons = &main_cons; tp = tty_alloc(&xencons_ttydevsw, cons); tty_makedev(tp, NULL, "%s%r", driver_name, 0); device_set_softc(dev, tp); callout_init_mtx(&cons->callout, tty_getlock(tp), 0); err = cons->ops->init(dev, tp, xencons_intr); if (err != 0) { device_printf(dev, "Unable to initialize the console (%d)\n", err); return (err); } /* register handler to flush console on shutdown */ if ((EVENTHANDLER_REGISTER(shutdown_post_sync, xencons_shutdown, tp, SHUTDOWN_PRI_DEFAULT)) == NULL) device_printf(dev, "shutdown event registration failed!\n"); return (0); } static int xencons_resume(device_t dev) { struct xencons_priv *cons; struct tty *tp; int err; tp = device_get_softc(dev); cons = tty_softc(tp); xen_intr_unbind(&cons->intr_handle); err = cons->ops->init(dev, tp, xencons_intr); if (err != 0) { device_printf(dev, "Unable to resume the console (%d)\n", err); return (err); } return (0); } static devclass_t xencons_devclass; static device_method_t xencons_methods[] = { DEVMETHOD(device_identify, xencons_identify), DEVMETHOD(device_probe, xencons_probe), DEVMETHOD(device_attach, xencons_attach), DEVMETHOD(device_resume, xencons_resume), DEVMETHOD_END }; static driver_t xencons_driver = { driver_name, xencons_methods, 0, }; DRIVER_MODULE(xc, xenpv, xencons_driver, xencons_devclass, 0, 0);