linux-kernel - Re: [PATCH 0/2] Revert patches fixing probing of interrupts

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Message-ID: <20191209215535.pw6ewyetskaet2o6@cantor>
Date:   Mon, 9 Dec 2019 14:55:35 -0700
From:   Jerry Snitselaar <jsnitsel@...hat.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     Stefan Berger <stefanb@...ux.ibm.com>,
        Stefan Berger <stefanb@...ux.vnet.ibm.com>,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, linux-security-module@...r.kernel.org
Subject: Re: [PATCH 0/2] Revert patches fixing probing of interrupts

On Mon Dec 09 19, Jarkko Sakkinen wrote:
>On Mon, Dec 02, 2019 at 11:55:20AM -0700, Jerry Snitselaar wrote:
>> On Sun Dec 01 19, Stefan Berger wrote:
>> > On 11/29/19 5:37 PM, Jarkko Sakkinen wrote:
>> > > On Tue, Nov 26, 2019 at 08:17:51AM -0500, Stefan Berger wrote:
>> > > > From: Stefan Berger <stefanb@...ux.ibm.com>
>> > > >
>> > > > Revert the patches that were fixing the probing of interrupts due
>> > > > to reports of interrupt stroms on some systems
>> > > Can you explain how reverting is going to fix the issue?
>> >
>> >
>> > The reverts fix 'the interrupt storm issue' that they are causing on
>> > some systems but don't fix the issue with the interrupt mode not being
>> > used. I was hoping Jerry would get access to a system faster but this
>> > didn't seem to be the case. So sending these patches seemed the better
>> > solution than leaving 5.4.x with the problem but going back to when it
>> > worked 'better.'
>> >
>>
>> I finally heard back from IT support, and unfortunately they don't
>> have any T490s systems to give out on temp loan. So I can only send
>> patched kernels to the end user that had the problem.
>
>At least it is a fact that tpm_chip_stop() is called too early and that
>is destined to cause issues.
>
>Should I bake a patch or do you have already something?
>
>/Jarkko
>

This is what I'm currently building:

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 270f43acbb77..17184c07eb51 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -899,13 +899,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
  
  	if (wait_startup(chip, 0) != 0) {
  		rc = -ENODEV;
-		goto out_err;
+		goto out_start;
  	}
  
  	/* Take control of the TPM's interrupt hardware and shut it off */
  	rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
  	if (rc < 0)
-		goto out_err;
+		goto out_start;
  
  	intmask |= TPM_INTF_CMD_READY_INT | TPM_INTF_LOCALITY_CHANGE_INT |
  		   TPM_INTF_DATA_AVAIL_INT | TPM_INTF_STS_VALID_INT;
@@ -914,9 +914,8 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
  
  	rc = tpm_chip_start(chip);
  	if (rc)
-		goto out_err;
+		goto out_start;
  	rc = tpm2_probe(chip);
-	tpm_chip_stop(chip);
  	if (rc)
  		goto out_err;
  
@@ -980,7 +979,6 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
  			goto out_err;
  		}
  
-		tpm_chip_start(chip);
  		chip->flags |= TPM_CHIP_FLAG_IRQ;
  		if (irq) {
  			tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
@@ -991,18 +989,17 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
  		} else {
  			tpm_tis_probe_irq(chip, intmask);
  		}
-		tpm_chip_stop(chip);
  	}
+	tpm_chip_stop(chip);
  
  	rc = tpm_chip_register(chip);
  	if (rc)
-		goto out_err;
-
-	if (chip->ops->clk_enable != NULL)
-		chip->ops->clk_enable(chip, false);
+		goto out_start;
  
  	return 0;
  out_err:
+	tpm_chip_stop(chip);
+out_start:
  	if ((chip->ops != NULL) && (chip->ops->clk_enable != NULL))
  		chip->ops->clk_enable(chip, false);