On 09/11/2017 12:00 PM, Thiebaud Weksteen via tpmdd-devel wrote:

With TPM 2.0 specification, the event logs may only be accessible by
calling an EFI Boot Service. Modify the EFI stub to copy the log area to
a new Linux-specific EFI configuration table so it remains accessible
once booted.

When calling this service, it is possible to specify the expected format
of the logs: TPM 1.2 (SHA1) or TPM 2.0 ("Crypto Agile"). For now, only the
first format is retrieved.

Signed-off-by: Thiebaud Weksteen <redacted>
---

[snip]

+void efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
+{

[snip]

+
+	/* Allocate space for the logs and copy them. */
+	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
+				sizeof(*log_tbl) + log_size,
+				(void **) &log_tbl);
+
+	if (status != EFI_SUCCESS) {
+		efi_printk(sys_table_arg,
+			   "Unable to allocate memory for event log\n");
+		return;
+	}

If this fails or any previous error that will prevent the event log table + logs
to be allocated, shouldn't tpm_read_log_efi() be notified somehow? Since AFAICT
it will still try to access them even if the EFI allocate_pool did not succeed.

+ */
+int __init efi_tpm_eventlog_init(void)
+{
+	struct linux_efi_tpm_eventlog *tbl;
+	unsigned int tbl_size;
+

The functions efi_retrieve_tpm2_eventlog_1_2() and tpm_read_log_efi() are using
log_tbl as variable name, so I would use it here too for consistency.

+	if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
+		return 0;
+
+	tbl = early_memremap(efi.tpm_log, sizeof(*tbl));
+	if (!tbl) {
+		pr_err("Failed to map TPM Event Log table @ 0x%lx\n",
+			efi.tpm_log);
+		return -ENOMEM;
+	}
+

Same question than before, if this fails then the table + logs memory won't be
reserved but tpm_read_log_efi() will still try to access it. I'm not sure what
is the correct way to notify though, maybe setting efi.tpm_log to 0 and then in
tpm_read_log_efi() check efi.tpm_log for 0 or EFI_INVALID_TABLE_ADDR instead?

+	tbl_size = sizeof(*tbl) + tbl->size;
+	memblock_reserve(efi.tpm_log, tbl_size);
+	early_memunmap(tbl, sizeof(*tbl));
+	return 0;

Best regards,
-- 
Javier Martinez Canillas
Software Engineer - Desktop Hardware Enablement
Red Hat