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path: root/drivers/char/tpm/xen-tpmfront.c
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Diffstat (limited to 'drivers/char/tpm/xen-tpmfront.c')
-rw-r--r--drivers/char/tpm/xen-tpmfront.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
index 656e8af95d52..911475d36800 100644
--- a/drivers/char/tpm/xen-tpmfront.c
+++ b/drivers/char/tpm/xen-tpmfront.c
@@ -10,6 +10,7 @@
#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>
@@ -39,6 +40,66 @@ enum status_bits {
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);