linux-kernel - [PATCH v11 04/14] tpm, tpm_tis: Do not skip reset of original interrupt vector

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Date:   Thu, 24 Nov 2022 14:55:28 +0100
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     peterhuewe@....de, jarkko@...nel.org, jgg@...pe.ca
Cc:     stefanb@...ux.vnet.ibm.com, linux@...ewoehner.de,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        jandryuk@...il.com, pmenzel@...gen.mpg.de, l.sanfilippo@...bus.com,
        LinoSanfilippo@....de, lukas@...ner.de, p.rosenberger@...bus.com
Subject: [PATCH v11 04/14] tpm, tpm_tis: Do not skip reset of original interrupt vector

From: Lino Sanfilippo <l.sanfilippo@...bus.com>

If in tpm_tis_probe_irq_single() an error occurs after the original
interrupt vector has been read, restore the interrupts before the error is
returned.

Since the caller does not check the error value, return -1 in any case that
the TPM_CHIP_FLAG_IRQ flag is not set. Since the return value of function
tpm_tis_gen_interrupt() is not longer used, make it a void function.

Fixes: 1107d065fdf1 ("tpm_tis: Introduce intermediate layer for TPM access")
Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
---
 drivers/char/tpm/tpm_tis_core.c | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 603b82ca56da..81b9726d3ed2 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -729,7 +729,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
+static void tpm_tis_gen_interrupt(struct tpm_chip *chip)
 {
 	const char *desc = "attempting to generate an interrupt";
 	u32 cap2;
@@ -738,7 +738,7 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
 
 	ret = request_locality(chip, 0);
 	if (ret < 0)
-		return ret;
+		return;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		ret = tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
@@ -746,8 +746,6 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
 		ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc, 0);
 
 	release_locality(chip, 0);
-
-	return ret;
 }
 
 /* Register the IRQ and issue a command that will cause an interrupt. If an
@@ -777,42 +775,37 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 
 	rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), irq);
 	if (rc < 0)
-		return rc;
+		goto restore_irqs;
 
 	rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &int_status);
 	if (rc < 0)
-		return rc;
+		goto restore_irqs;
 
 	/* Clear all existing */
 	rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), int_status);
 	if (rc < 0)
-		return rc;
-
+		goto restore_irqs;
 	/* Turn on */
 	rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality),
 			     intmask | TPM_GLOBAL_INT_ENABLE);
 	if (rc < 0)
-		return rc;
+		goto restore_irqs;
 
 	clear_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
 
 	/* Generate an interrupt by having the core call through to
 	 * tpm_tis_send
 	 */
-	rc = tpm_tis_gen_interrupt(chip);
-	if (rc < 0)
-		return rc;
+	tpm_tis_gen_interrupt(chip);
 
+restore_irqs:
 	/* tpm_tis_send will either confirm the interrupt is working or it
 	 * will call disable_irq which undoes all of the above.
 	 */
 	if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
-		rc = tpm_tis_write8(priv, original_int_vec,
-				TPM_INT_VECTOR(priv->locality));
-		if (rc < 0)
-			return rc;
-
-		return 1;
+		tpm_tis_write8(priv, original_int_vec,
+			       TPM_INT_VECTOR(priv->locality));
+		return -1;
 	}
 
 	return 0;
-- 
2.36.1