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tpm: Add support for event log pointer found in TPM2 ACPI table
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In case a TPM2 is attached, search for a TPM2 ACPI table when trying
to get the event log from ACPI. If one is found, use it to get the
start and length of the log area. This allows non-UEFI systems, such
as SeaBIOS, to pass an event log when using a TPM2.

Cc: Peter Huewe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Signed-off-by: Stefan Berger <[email protected]>
Reviewed-by: Jerry Snitselaar <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
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stefanberger authored and Jarkko Sakkinen committed Jul 24, 2020
1 parent 1830611 commit 85467f6
Showing 1 changed file with 42 additions and 21 deletions.
63 changes: 42 additions & 21 deletions drivers/char/tpm/eventlog/acpi.c
Original file line number Diff line number Diff line change
Expand Up @@ -49,9 +49,9 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
void __iomem *virt;
u64 len, start;
struct tpm_bios_log *log;

if (chip->flags & TPM_CHIP_FLAG_TPM2)
return -ENODEV;
struct acpi_table_tpm2 *tbl;
struct acpi_tpm2_phy *tpm2_phy;
int format;

log = &chip->log;

Expand All @@ -61,23 +61,44 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
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 (chip->flags & TPM_CHIP_FLAG_TPM2) {
status = acpi_get_table("TPM2", 1,
(struct acpi_table_header **)&tbl);
if (ACPI_FAILURE(status))
return -ENODEV;

if (tbl->header.length <
sizeof(*tbl) + sizeof(struct acpi_tpm2_phy))
return -ENODEV;

tpm2_phy = (void *)tbl + sizeof(*tbl);
len = tpm2_phy->log_area_minimum_length;

start = tpm2_phy->log_area_start_address;
if (!start || !len)
return -ENODEV;

format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
} else {
/* 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;
}

format = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
}
if (!len) {
dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
Expand All @@ -98,7 +119,7 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
memcpy_fromio(log->bios_event_log, virt, len);

acpi_os_unmap_iomem(virt, len);
return EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
return format;

err:
kfree(log->bios_event_log);
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