Re: [PATCH] tpm_tis: Revert "tpm_tis: Disable interrupts on ThinkPad T490s"

[Jerry Snitselaar]

On Mon, Aug 14, 2023 at 07:40:53PM +0300, Jarkko Sakkinen wrote:
> Since for MMIO driver using FIFO registers, also known as tpm_tis, the
> default (and tbh recommended) behaviour is now the polling mode, the
> "tristate" workaround is no longer for benefit.
> 
> If someone wants to explicitly enable IRQs for a TPM chip that should be
> without question allowed. It could very well be a piece hardware in the
> existing deny list because of e.g. firmware update or something similar.
> 
> While at it, document the module parameter, as this was not done in 2006
> when it first appeared in the mainline.
> 
> Link: https://lore.kernel.org/linux-integrity/20201015214430.17937-1-jsnitsel@xxxxxxxxxx/
> Link: https://lore.kernel.org/all/1145393776.4829.19.camel@localhost.localdomain/
> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>

I was just typing an email to say that it looks like 6aaf663ee04a ("tpm_tis: Opt-in interrupts") will require
updating tpm_tis_disable_irq(), but you are already dealing with it. :)

Reviewed-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>

> ---
>  .../admin-guide/kernel-parameters.txt         |  7 ++
>  drivers/char/tpm/tpm_tis.c                    | 93 +------------------
>  2 files changed, 9 insertions(+), 91 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 722b6eca2e93..6354aa779178 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -6340,6 +6340,13 @@
>  			This will guarantee that all the other pcrs
>  			are saved.
>  
> +	tpm_tis.interrupts= [HW,TPM]
> +			Enable interrupts for the MMIO based physical layer
> +			for the FIFO interface. By default it is set to false
> +			(0). For more information about TPM hardware interfaces
> +			defined by Trusted Computing Group (TCG) look up to
> +			https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
> +
>  	tp_printk	[FTRACE]
>  			Have the tracepoints sent to printk as well as the
>  			tracing ring buffer. This is useful for early boot up
> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> index 7fa3d91042b2..077fdb73740c 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -27,7 +27,6 @@
>  #include <linux/of.h>
>  #include <linux/of_device.h>
>  #include <linux/kernel.h>
> -#include <linux/dmi.h>
>  #include "tpm.h"
>  #include "tpm_tis_core.h"
>  
> @@ -89,8 +88,8 @@ static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr)
>  	tpm_tis_flush(iobase);
>  }
>  
> -static int interrupts;
> -module_param(interrupts, int, 0444);
> +static bool interrupts;
> +module_param(interrupts, bool, 0444);
>  MODULE_PARM_DESC(interrupts, "Enable interrupts");
>  
>  static bool itpm;
> @@ -103,92 +102,6 @@ module_param(force, bool, 0444);
>  MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
>  #endif
>  
> -static int tpm_tis_disable_irq(const struct dmi_system_id *d)
> -{
> -	if (interrupts == -1) {
> -		pr_notice("tpm_tis: %s detected: disabling interrupts.\n", d->ident);
> -		interrupts = 0;
> -	}
> -
> -	return 0;
> -}
> -
> -static const struct dmi_system_id tpm_tis_dmi_table[] = {
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "Framework Laptop (12th Gen Intel Core)",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "Framework"),
> -			DMI_MATCH(DMI_PRODUCT_NAME, "Laptop (12th Gen Intel Core)"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "Framework Laptop (13th Gen Intel Core)",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "Framework"),
> -			DMI_MATCH(DMI_PRODUCT_NAME, "Laptop (13th Gen Intel Core)"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "ThinkPad T490s",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> -			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T490s"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "ThinkStation P360 Tiny",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> -			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkStation P360 Tiny"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "ThinkPad L490",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> -			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad L490"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "ThinkPad L590",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> -			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad L590"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "ThinkStation P620",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> -			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkStation P620"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "TUXEDO InfinityBook S 15/17 Gen7",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
> -			DMI_MATCH(DMI_PRODUCT_NAME, "TUXEDO InfinityBook S 15/17 Gen7"),
> -		},
> -	},
> -	{
> -		.callback = tpm_tis_disable_irq,
> -		.ident = "UPX-TGL",
> -		.matches = {
> -			DMI_MATCH(DMI_SYS_VENDOR, "AAEON"),
> -			DMI_MATCH(DMI_PRODUCT_NAME, "UPX-TGL01"),
> -		},
> -	},
> -	{}
> -};
> -
>  #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
>  static int has_hid(struct acpi_device *dev, const char *hid)
>  {
> @@ -312,8 +225,6 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info)
>  	int irq = -1;
>  	int rc;
>  
> -	dmi_check_system(tpm_tis_dmi_table);
> -
>  	rc = check_acpi_tpm2(dev);
>  	if (rc)
>  		return rc;
> -- 
> 2.39.2
>