On Sun, Jun 20, 2021 at 04:18:09PM -0700, Hao Wu wrote: > This is a fix for the ATMEL TPM crash bug reported in > https://patchwork.kernel.org/project/linux-integrity/patch/20200926223150.109645-1-hao.wu@xxxxxxxxxx/ > > According to the discussions in the original thread, > we don't want to revert the timeout of wait_for_tpm_stat > for non-ATMEL chips, which brings back the performance cost. > For investigation and analysis of why wait_for_tpm_stat > caused the issue, and how the regression was introduced, > please read the original thread above. > > Thus the proposed fix here is to only revert the timeout > for ATMEL chips by checking the vendor ID. > > Test Plan: > - Run fixed kernel with ATMEL TPM chips and see crash > has been fixed. > - Run fixed kernel with non-ATMEL TPM chips, and confirm > the timeout has not been changed. Please move test plan right before diffstat if you wan to include such, so that it does not go into the commit log. > --- > drivers/char/tpm/tpm.h | 9 ++++++++- > drivers/char/tpm/tpm_tis_core.c | 19 +++++++++++++++++-- > include/linux/tpm.h | 2 ++ > 3 files changed, 27 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h > index 283f78211c3a..bc6aa7f9e119 100644 > --- a/drivers/char/tpm/tpm.h > +++ b/drivers/char/tpm/tpm.h > @@ -42,7 +42,9 @@ enum tpm_timeout { > TPM_TIMEOUT_RANGE_US = 300, /* usecs */ > TPM_TIMEOUT_POLL = 1, /* msecs */ > TPM_TIMEOUT_USECS_MIN = 100, /* usecs */ > - TPM_TIMEOUT_USECS_MAX = 500 /* usecs */ > + TPM_TIMEOUT_USECS_MAX = 500, /* usecs */ > + TPM_TIMEOUT_WAIT_STAT = 500, /* usecs */ > + TPM_ATML_TIMEOUT_WAIT_STAT = 15000 /* usecs */ > }; > > /* TPM addresses */ > @@ -189,6 +191,11 @@ static inline void tpm_msleep(unsigned int delay_msec) > delay_msec * 1000); > }; > > +static inline void tpm_usleep(unsigned int delay_usec) > +{ > + usleep_range(delay_usec - TPM_TIMEOUT_RANGE_US, delay_usec); > +}; > + > int tpm_chip_start(struct tpm_chip *chip); > void tpm_chip_stop(struct tpm_chip *chip); > struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip); > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 55b9d3965ae1..9ddd4edfe1c2 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -80,8 +80,12 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, > } > } else { > do { > - usleep_range(TPM_TIMEOUT_USECS_MIN, > - TPM_TIMEOUT_USECS_MAX); > + if (chip->timeout_wait_stat && > + chip->timeout_wait_stat >= TPM_TIMEOUT_WAIT_STAT) { > + tpm_usleep((unsigned int)(chip->timeout_wait_stat)); > + } else { > + tpm_usleep((unsigned int)(TPM_TIMEOUT_WAIT_STAT)); > + } > status = chip->ops->status(chip); > if ((status & mask) == mask) > return 0; > @@ -934,6 +938,8 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > chip->timeout_b = msecs_to_jiffies(TIS_TIMEOUT_B_MAX); > chip->timeout_c = msecs_to_jiffies(TIS_TIMEOUT_C_MAX); > chip->timeout_d = msecs_to_jiffies(TIS_TIMEOUT_D_MAX); > + /* init timeout for wait_for_tpm_stat */ > + chip->timeout_wait_stat = TPM_TIMEOUT_WAIT_STAT; > priv->phy_ops = phy_ops; > dev_set_drvdata(&chip->dev, priv); > > @@ -983,6 +989,15 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > > priv->manufacturer_id = vendor; > > + switch (priv->manufacturer_id) { > + case TPM_VID_ATML: > + /* ATMEL chip needs longer timeout to avoid crash */ > + chip->timeout_wait_stat = TPM_ATML_TIMEOUT_WAIT_STAT; > + break; > + default: > + chip->timeout_wait_stat = TPM_TIMEOUT_WAIT_STAT; > + } > + > rc = tpm_tis_read8(priv, TPM_RID(0), &rid); > if (rc < 0) > goto out_err; > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > index aa11fe323c56..35f2a0260d76 100644 > --- a/include/linux/tpm.h > +++ b/include/linux/tpm.h > @@ -150,6 +150,7 @@ struct tpm_chip { > bool timeout_adjusted; > unsigned long duration[TPM_NUM_DURATIONS]; /* jiffies */ > bool duration_adjusted; > + unsigned long timeout_wait_stat; /* usecs */ > > struct dentry *bios_dir[TPM_NUM_EVENT_LOG_FILES]; > > @@ -269,6 +270,7 @@ enum tpm2_cc_attrs { > #define TPM_VID_INTEL 0x8086 > #define TPM_VID_WINBOND 0x1050 > #define TPM_VID_STM 0x104A > +#define TPM_VID_ATML 0x1114 > > enum tpm_chip_flags { > TPM_CHIP_FLAG_TPM2 = BIT(1), > -- > 2.29.0.vfs.0.0 > > /Jarkko
