On Wed, Mar 29, 2017 at 12:43:26AM -0700, Petr Vandrovec wrote:
> From: Petr Vandrovec <[email protected]>
> 
> Latest draft of TPM 2 ACPI specification added TCG log start/length
> to the TPM2 ACPI table.  So Linux kernel can now read it without
> having to get involved with boot loader, same way TPM1/TCPA tables
> work.
> 
> Signed-off-by: Petr Vandrovec <[email protected]>
> ---
>  drivers/char/tpm/tpm_acpi.c | 70 
> ++++++++++++++++++++++++++++-----------------
>  1 file changed, 43 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c
> index 169edf3ce86d..e48b1503220c 100644
> --- a/drivers/char/tpm/tpm_acpi.c
> +++ b/drivers/char/tpm/tpm_acpi.c
> @@ -48,46 +48,62 @@ struct acpi_tcpa {
>  /* read binary bios log */
>  int tpm_read_log_acpi(struct tpm_chip *chip)
>  {
> -     struct acpi_tcpa *buff;
>       acpi_status status;
>       void __iomem *virt;
>       u64 len, start;
>       struct tpm_bios_log *log;
>  
> -     if (chip->flags & TPM_CHIP_FLAG_TPM2)
> -             return -ENODEV;
> -
> -     log = &chip->log;
> -
>       /* Unfortuntely ACPI does not associate the event log with a specific
>        * TPM, like PPI. Thus all ACPI TPMs will read the same log.
>        */
>       if (!chip->acpi_dev_handle)
>               return -ENODEV;
>  
> -     /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
> -     status = acpi_get_table(ACPI_SIG_TCPA, 1,
> -                             (struct acpi_table_header **)&buff);
> -
> -     if (ACPI_FAILURE(status))
> -             return -ENODEV;
> -
> -     switch(buff->platform_class) {
> -     case BIOS_SERVER:
> -             len = buff->server.log_max_len;
> -             start = buff->server.log_start_addr;
> -             break;
> -     case BIOS_CLIENT:
> -     default:
> -             len = buff->client.log_max_len;
> -             start = buff->client.log_start_addr;
> -             break;
> -     }
> -     if (!len) {
> -             dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
> -             return -EIO;
> +     if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> +             struct acpi_table_tpm2 *buff;
> +
> +             /* Find TPM2 entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
> +             status = acpi_get_table(ACPI_SIG_TPM2, 1,
> +                                     (struct acpi_table_header **)&buff);
> +
> +             if (ACPI_FAILURE(status) || buff->header.length < 
> ACPI_TPM2_SIZE_WITH_LOG)
> +                     return -ENODEV;
> +
> +             len = buff->minimum_log_length;
> +             start = buff->log_address;
> +             if (!len) {
> +                     dev_warn(&chip->dev, "%s: TPM2 log area empty\n", 
> __func__);
> +                     return -EIO;
> +             }
> +     } else {
> +             struct acpi_tcpa *buff;
> +
> +             /* Find TCPA entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
> +             status = acpi_get_table(ACPI_SIG_TCPA, 1,
> +                                     (struct acpi_table_header **)&buff);
> +
> +             if (ACPI_FAILURE(status))
> +                     return -ENODEV;
> +
> +             switch(buff->platform_class) {
> +             case BIOS_SERVER:
> +                     len = buff->server.log_max_len;
> +                     start = buff->server.log_start_addr;
> +                     break;
> +             case BIOS_CLIENT:
> +             default:
> +                     len = buff->client.log_max_len;
> +                     start = buff->client.log_start_addr;
> +                     break;
> +             }
> +             if (!len) {
> +                     dev_warn(&chip->dev, "%s: TCPA log area empty\n", 
> __func__);
> +                     return -EIO;
> +             }
>       }
>  
> +     log = &chip->log;
> +
>       /* malloc EventLog space */
>       log->bios_event_log = kmalloc(len, GFP_KERNEL);
>       if (!log->bios_event_log)
> -- 
> 2.11.0
> 

It would be a better idea to rename the existing function as
tpm1_read_log_acpi() and add a new function called
tpm2_read_log_acpi().

/Jarkko

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