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Subject[PATCH v2] tpm: Get TCG log from TPM2 ACPI table for tpm2 systems
Date
For TPM2-based systems, retrieve the TCG log from the TPM2 ACPI table.

Signed-off-by: Jordan Hand <jordanhand22@gmail.com>
---
v2:
- Apologies, v1 had a silly compile error

drivers/char/tpm/eventlog/acpi.c | 67 +++++++++++++++++++++++---------
1 file changed, 48 insertions(+), 19 deletions(-)

diff --git a/drivers/char/tpm/eventlog/acpi.c b/drivers/char/tpm/eventlog/acpi.c
index 63ada5e53f13..b945c4ff3af6 100644
--- a/drivers/char/tpm/eventlog/acpi.c
+++ b/drivers/char/tpm/eventlog/acpi.c
@@ -41,17 +41,31 @@ struct acpi_tcpa {
};
};

+struct acpi_tpm2 {
+ struct acpi_table_header hdr;
+ u16 platform_class;
+ u16 reserved;
+ u64 control_area_addr;
+ u32 start_method;
+ u8 start_method_params[12];
+ u32 log_max_len;
+ u64 log_start_addr;
+} __packed;
+
/* read binary bios log */
int tpm_read_log_acpi(struct tpm_chip *chip)
{
- struct acpi_tcpa *buff;
+ struct acpi_table_header *buff;
+ struct acpi_tcpa *tcpa;
+ struct acpi_tpm2 *tpm2;
+
acpi_status status;
void __iomem *virt;
u64 len, start;
+ int log_type;
struct tpm_bios_log *log;
-
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- return -ENODEV;
+ bool is_tpm2 = chip->flags & TPM_CHIP_FLAG_TPM2;
+ acpi_string table_sig;

log = &chip->log;

@@ -61,26 +75,41 @@ 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);
+ /* Find TCPA or TPM2 entry in RSDT (ACPI_LOGICAL_ADDRESSING) */
+ table_sig = is_tpm2 ? ACPI_SIG_TPM2 : ACPI_SIG_TCPA;
+ status = acpi_get_table(table_sig, 1, &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 log_max_len and log_start_addr are set, start_method_params will
+ * be 12 bytes, according to TCG ACPI spec. If start_method_params is
+ * fewer than 12 bytes, the TCG log is not available
+ */
+ if (is_tpm2 && (buff->length == sizeof(struct acpi_tpm2))) {
+ tpm2 = (struct acpi_tpm2 *)buff;
+ len = tpm2->log_max_len;
+ start = tpm2->log_start_addr;
+ log_type = EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
+ } else {
+ tcpa = (struct acpi_tcpa *)buff;
+ switch (tcpa->platform_class) {
+ case BIOS_SERVER:
+ len = tcpa->server.log_max_len;
+ start = tcpa->server.log_start_addr;
+ break;
+ case BIOS_CLIENT:
+ default:
+ len = tcpa->client.log_max_len;
+ start = tcpa->client.log_start_addr;
+ break;
+ }
+ log_type = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
}
+
if (!len) {
- dev_warn(&chip->dev, "%s: TCPA log area empty\n", __func__);
+ dev_warn(&chip->dev, "%s: %s log area empty\n",
+ table_sig, __func__);
return -EIO;
}

@@ -98,7 +127,7 @@ 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 log_type;

err:
kfree(log->bios_event_log);
--
2.20.1
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