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List:       tpmdd-devel
Subject:    [tpmdd-devel] [PATCH V2 2/2] Fix cancellation of TPM commands (interrupt mode)
From:       Stefan Berger <stefanb () linux ! vnet ! ibm ! com>
Date:       2012-11-26 11:33:01
Message-ID: 20121126113419.028089772 () linux ! vnet ! ibm ! com
[Download RAW message or body]

Support cancellation of TPM commands when driver is used in interrupt
mode.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

---
 drivers/char/tpm/tpm.c     |   29 ++++++++++++++++++++++++-----
 drivers/char/tpm/tpm.h     |    2 +-
 drivers/char/tpm/tpm_tis.c |   12 ++++++------
 3 files changed, 31 insertions(+), 12 deletions(-)

Index: linux-2.6/drivers/char/tpm/tpm.c
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm.c
+++ linux-2.6/drivers/char/tpm/tpm.c
@@ -1075,12 +1075,28 @@ ssize_t tpm_store_cancel(struct device *
 }
 EXPORT_SYMBOL_GPL(tpm_store_cancel);
 
+bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, bool check_cancel,
+                            bool *canceled)
+{
+	u8 status = chip->vendor.status(chip);
+
+	*canceled = false;
+	if ((status & mask) == mask)
+		return true;
+	if (check_cancel && chip->vendor.req_canceled(status)) {
+		*canceled = true;
+		return true;
+	}
+	return false;
+}
+
 int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
-			 wait_queue_head_t *queue)
+		      wait_queue_head_t *queue, bool check_cancel)
 {
 	unsigned long stop;
 	long rc;
 	u8 status;
+	bool canceled = false;
 
 	/* check current status */
 	status = chip->vendor.status(chip);
@@ -1095,11 +1111,14 @@ again:
 		if ((long)timeout <= 0)
 			return -ETIME;
 		rc = wait_event_interruptible_timeout(*queue,
-						      ((chip->vendor.status(chip)
-						      & mask) == mask),
-						      timeout);
-		if (rc > 0)
+			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;
Index: linux-2.6/drivers/char/tpm/tpm.h
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm.h
+++ linux-2.6/drivers/char/tpm/tpm.h
@@ -326,7 +326,7 @@ extern void tpm_remove_hardware(struct d
 extern int tpm_pm_suspend(struct device *);
 extern int tpm_pm_resume(struct device *);
 extern int wait_for_tpm_stat(struct tpm_chip *, u8, unsigned long,
-			     wait_queue_head_t *);
+			     wait_queue_head_t *, bool);
 
 #ifdef CONFIG_ACPI
 extern int tpm_add_ppi(struct kobject *);
Index: linux-2.6/drivers/char/tpm/tpm_tis.c
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm_tis.c
+++ linux-2.6/drivers/char/tpm/tpm_tis.c
@@ -198,7 +198,7 @@ static int recv_data(struct tpm_chip *ch
 	       wait_for_tpm_stat(chip,
 				 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 				 chip->vendor.timeout_c,
-				 &chip->vendor.read_queue)
+				 &chip->vendor.read_queue, true)
 	       == 0) {
 		burstcnt = get_burstcount(chip);
 		for (; burstcnt > 0 && size < count; burstcnt--)
@@ -241,7 +241,7 @@ static int tpm_tis_recv(struct tpm_chip
 	}
 
 	wait_for_tpm_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
-			  &chip->vendor.int_queue);
+			  &chip->vendor.int_queue, false);
 	status = tpm_tis_status(chip);
 	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
 		dev_err(chip->dev, "Error left over data\n");
@@ -277,7 +277,7 @@ static int tpm_tis_send_data(struct tpm_
 		tpm_tis_ready(chip);
 		if (wait_for_tpm_stat
 		    (chip, TPM_STS_COMMAND_READY, chip->vendor.timeout_b,
-		     &chip->vendor.int_queue) < 0) {
+		     &chip->vendor.int_queue, false) < 0) {
 			rc = -ETIME;
 			goto out_err;
 		}
@@ -292,7 +292,7 @@ static int tpm_tis_send_data(struct tpm_
 		}
 
 		wait_for_tpm_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
-				  &chip->vendor.int_queue);
+				  &chip->vendor.int_queue, false);
 		status = tpm_tis_status(chip);
 		if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
 			rc = -EIO;
@@ -304,7 +304,7 @@ static int tpm_tis_send_data(struct tpm_
 	iowrite8(buf[count],
 		 chip->vendor.iobase + TPM_DATA_FIFO(chip->vendor.locality));
 	wait_for_tpm_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c,
-			  &chip->vendor.int_queue);
+			  &chip->vendor.int_queue, false);
 	status = tpm_tis_status(chip);
 	if ((status & TPM_STS_DATA_EXPECT) != 0) {
 		rc = -EIO;
@@ -342,7 +342,7 @@ static int tpm_tis_send(struct tpm_chip
 		if (wait_for_tpm_stat
 		    (chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 		     tpm_calc_ordinal_duration(chip, ordinal),
-		     &chip->vendor.read_queue) < 0) {
+		     &chip->vendor.read_queue, false) < 0) {
 			rc = -ETIME;
 			goto out_err;
 		}


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