Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 442 insertions, 0 deletions

diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
new file mode 100644
index 000000000..379291826
--- /dev/null
+++ b/drivers/char/tpm/xen-tpmfront.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Implementation of the Xen vTPM device frontend
+ *
+ * Author:  Daniel De Graaf <dgdegra@tycho.nsa.gov>
+ */
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/freezer.h>
+#include <xen/xen.h>
+#include <xen/events.h>
+#include <xen/interface/io/tpmif.h>
+#include <xen/grant_table.h>
+#include <xen/xenbus.h>
+#include <xen/page.h>
+#include "tpm.h"
+#include <xen/platform_pci.h>
+
+struct tpm_private {
+	struct tpm_chip *chip;
+	struct xenbus_device *dev;
+
+	struct vtpm_shared_page *shr;
+
+	unsigned int evtchn;
+	int ring_ref;
+	domid_t backend_id;
+	int irq;
+	wait_queue_head_t read_queue;
+};
+
+enum status_bits {
+	VTPM_STATUS_RUNNING  = 0x1,
+	VTPM_STATUS_IDLE     = 0x2,
+	VTPM_STATUS_RESULT   = 0x4,
+	VTPM_STATUS_CANCELED = 0x8,
+};
+
+static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
+					bool check_cancel, bool *canceled)
+{
+	u8 status = chip->ops->status(chip);
+
+	*canceled = false;
+	if ((status & mask) == mask)
+		return true;
+	if (check_cancel && chip->ops->req_canceled(chip, status)) {
+		*canceled = true;
+		return true;
+	}
+	return false;
+}
+
+static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
+		unsigned long timeout, wait_queue_head_t *queue,
+		bool check_cancel)
+{
+	unsigned long stop;
+	long rc;
+	u8 status;
+	bool canceled = false;
+
+	/* check current status */
+	status = chip->ops->status(chip);
+	if ((status & mask) == mask)
+		return 0;
+
+	stop = jiffies + timeout;
+
+	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
+again:
+		timeout = stop - jiffies;
+		if ((long)timeout <= 0)
+			return -ETIME;
+		rc = wait_event_interruptible_timeout(*queue,
+			wait_for_tpm_stat_cond(chip, mask, check_cancel,
+					       &canceled),
+			timeout);
+		if (rc > 0) {
+			if (canceled)
+				return -ECANCELED;
+			return 0;
+		}
+		if (rc == -ERESTARTSYS && freezing(current)) {
+			clear_thread_flag(TIF_SIGPENDING);
+			goto again;
+		}
+	} else {
+		do {
+			tpm_msleep(TPM_TIMEOUT);
+			status = chip->ops->status(chip);
+			if ((status & mask) == mask)
+				return 0;
+		} while (time_before(jiffies, stop));
+	}
+	return -ETIME;
+}
+
+static u8 vtpm_status(struct tpm_chip *chip)
+{
+	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
+	switch (priv->shr->state) {
+	case VTPM_STATE_IDLE:
+		return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED;
+	case VTPM_STATE_FINISH:
+		return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT;
+	case VTPM_STATE_SUBMIT:
+	case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */
+		return VTPM_STATUS_RUNNING;
+	default:
+		return 0;
+	}
+}
+
+static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
+{
+	return status & VTPM_STATUS_CANCELED;
+}
+
+static void vtpm_cancel(struct tpm_chip *chip)
+{
+	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
+	priv->shr->state = VTPM_STATE_CANCEL;
+	wmb();
+	notify_remote_via_evtchn(priv->evtchn);
+}
+
+static size_t shr_data_offset(struct vtpm_shared_page *shr)
+{
+	return struct_size(shr, extra_pages, shr->nr_extra_pages);
+}
+
+static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
+	struct vtpm_shared_page *shr = priv->shr;
+	size_t offset = shr_data_offset(shr);
+
+	u32 ordinal;
+	unsigned long duration;
+
+	if (offset > PAGE_SIZE)
+		return -EINVAL;
+
+	if (offset + count > PAGE_SIZE)
+		return -EINVAL;
+
+	/* Wait for completion of any existing command or cancellation */
+	if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->timeout_c,
+			&priv->read_queue, true) < 0) {
+		vtpm_cancel(chip);
+		return -ETIME;
+	}
+
+	memcpy(offset + (u8 *)shr, buf, count);
+	shr->length = count;
+	barrier();
+	shr->state = VTPM_STATE_SUBMIT;
+	wmb();
+	notify_remote_via_evtchn(priv->evtchn);
+
+	ordinal = be32_to_cpu(((struct tpm_header *)buf)->ordinal);
+	duration = tpm_calc_ordinal_duration(chip, ordinal);
+
+	if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
+			&priv->read_queue, true) < 0) {
+		/* got a signal or timeout, try to cancel */
+		vtpm_cancel(chip);
+		return -ETIME;
+	}
+
+	return 0;
+}
+
+static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
+	struct vtpm_shared_page *shr = priv->shr;
+	size_t offset = shr_data_offset(shr);
+	size_t length = shr->length;
+
+	if (shr->state == VTPM_STATE_IDLE)
+		return -ECANCELED;
+
+	/* In theory the wait at the end of _send makes this one unnecessary */
+	if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->timeout_c,
+			&priv->read_queue, true) < 0) {
+		vtpm_cancel(chip);
+		return -ETIME;
+	}
+
+	if (offset > PAGE_SIZE)
+		return -EIO;
+
+	if (offset + length > PAGE_SIZE)
+		length = PAGE_SIZE - offset;
+
+	if (length > count)
+		length = count;
+
+	memcpy(buf, offset + (u8 *)shr, length);
+
+	return length;
+}
+
+static const struct tpm_class_ops tpm_vtpm = {
+	.status = vtpm_status,
+	.recv = vtpm_recv,
+	.send = vtpm_send,
+	.cancel = vtpm_cancel,
+	.req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
+	.req_complete_val  = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
+	.req_canceled      = vtpm_req_canceled,
+};
+
+static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
+{
+	struct tpm_private *priv = dev_id;
+
+	switch (priv->shr->state) {
+	case VTPM_STATE_IDLE:
+	case VTPM_STATE_FINISH:
+		wake_up_interruptible(&priv->read_queue);
+		break;
+	case VTPM_STATE_SUBMIT:
+	case VTPM_STATE_CANCEL:
+	default:
+		break;
+	}
+	return IRQ_HANDLED;
+}
+
+static int setup_chip(struct device *dev, struct tpm_private *priv)
+{
+	struct tpm_chip *chip;
+
+	chip = tpmm_chip_alloc(dev, &tpm_vtpm);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+
+	init_waitqueue_head(&priv->read_queue);
+
+	priv->chip = chip;
+	dev_set_drvdata(&chip->dev, priv);
+
+	return 0;
+}
+
+/* caller must clean up in case of errors */
+static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
+{
+	struct xenbus_transaction xbt;
+	const char *message = NULL;
+	int rv;
+
+	rv = xenbus_setup_ring(dev, GFP_KERNEL, (void **)&priv->shr, 1,
+			       &priv->ring_ref);
+	if (rv < 0)
+		return rv;
+
+	rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
+	if (rv)
+		return rv;
+
+	rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
+				       "tpmif", priv);
+	if (rv <= 0) {
+		xenbus_dev_fatal(dev, rv, "allocating TPM irq");
+		return rv;
+	}
+	priv->irq = rv;
+
+ again:
+	rv = xenbus_transaction_start(&xbt);
+	if (rv) {
+		xenbus_dev_fatal(dev, rv, "starting transaction");
+		return rv;
+	}
+
+	rv = xenbus_printf(xbt, dev->nodename,
+			"ring-ref", "%u", priv->ring_ref);
+	if (rv) {
+		message = "writing ring-ref";
+		goto abort_transaction;
+	}
+
+	rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
+			priv->evtchn);
+	if (rv) {
+		message = "writing event-channel";
+		goto abort_transaction;
+	}
+
+	rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
+	if (rv) {
+		message = "writing feature-protocol-v2";
+		goto abort_transaction;
+	}
+
+	rv = xenbus_transaction_end(xbt, 0);
+	if (rv == -EAGAIN)
+		goto again;
+	if (rv) {
+		xenbus_dev_fatal(dev, rv, "completing transaction");
+		return rv;
+	}
+
+	xenbus_switch_state(dev, XenbusStateInitialised);
+
+	return 0;
+
+ abort_transaction:
+	xenbus_transaction_end(xbt, 1);
+	if (message)
+		xenbus_dev_error(dev, rv, "%s", message);
+
+	return rv;
+}
+
+static void ring_free(struct tpm_private *priv)
+{
+	if (!priv)
+		return;
+
+	xenbus_teardown_ring((void **)&priv->shr, 1, &priv->ring_ref);
+
+	if (priv->irq)
+		unbind_from_irqhandler(priv->irq, priv);
+
+	kfree(priv);
+}
+
+static int tpmfront_probe(struct xenbus_device *dev,
+		const struct xenbus_device_id *id)
+{
+	struct tpm_private *priv;
+	int rv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
+		return -ENOMEM;
+	}
+
+	rv = setup_chip(&dev->dev, priv);
+	if (rv) {
+		kfree(priv);
+		return rv;
+	}
+
+	rv = setup_ring(dev, priv);
+	if (rv) {
+		ring_free(priv);
+		return rv;
+	}
+
+	tpm_get_timeouts(priv->chip);
+
+	return tpm_chip_register(priv->chip);
+}
+
+static int tpmfront_remove(struct xenbus_device *dev)
+{
+	struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
+	struct tpm_private *priv = dev_get_drvdata(&chip->dev);
+	tpm_chip_unregister(chip);
+	ring_free(priv);
+	dev_set_drvdata(&chip->dev, NULL);
+	return 0;
+}
+
+static int tpmfront_resume(struct xenbus_device *dev)
+{
+	/* A suspend/resume/migrate will interrupt a vTPM anyway */
+	tpmfront_remove(dev);
+	return tpmfront_probe(dev, NULL);
+}
+
+static void backend_changed(struct xenbus_device *dev,
+		enum xenbus_state backend_state)
+{
+	switch (backend_state) {
+	case XenbusStateInitialised:
+	case XenbusStateConnected:
+		if (dev->state == XenbusStateConnected)
+			break;
+
+		if (!xenbus_read_unsigned(dev->otherend, "feature-protocol-v2",
+					  0)) {
+			xenbus_dev_fatal(dev, -EINVAL,
+					"vTPM protocol 2 required");
+			return;
+		}
+		xenbus_switch_state(dev, XenbusStateConnected);
+		break;
+
+	case XenbusStateClosing:
+	case XenbusStateClosed:
+		device_unregister(&dev->dev);
+		xenbus_frontend_closed(dev);
+		break;
+	default:
+		break;
+	}
+}
+
+static const struct xenbus_device_id tpmfront_ids[] = {
+	{ "vtpm" },
+	{ "" }
+};
+MODULE_ALIAS("xen:vtpm");
+
+static struct xenbus_driver tpmfront_driver = {
+	.ids = tpmfront_ids,
+	.probe = tpmfront_probe,
+	.remove = tpmfront_remove,
+	.resume = tpmfront_resume,
+	.otherend_changed = backend_changed,
+};
+
+static int __init xen_tpmfront_init(void)
+{
+	if (!xen_domain())
+		return -ENODEV;
+
+	if (!xen_has_pv_devices())
+		return -ENODEV;
+
+	return xenbus_register_frontend(&tpmfront_driver);
+}
+module_init(xen_tpmfront_init);
+
+static void __exit xen_tpmfront_exit(void)
+{
+	xenbus_unregister_driver(&tpmfront_driver);
+}
+module_exit(xen_tpmfront_exit);
+
+MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
+MODULE_DESCRIPTION("Xen vTPM Driver");
+MODULE_LICENSE("GPL");