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[PATCH v9 1/2] tpm: enhance read_log_of() to support Physical TPM event log

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Physical TPMs use Open Firmware Device Tree bindings that are similar
to the IBM Power virtual TPM to support event log. However, these
properties store the values in different endianness for Physical
and Virtual TPM.

This patch fixes the endianness issue by doing appropriate conversion
based on Physical or Virtual TPM.

Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/tpm_of.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 7dee42d7..de57d4a 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -27,6 +27,8 @@ int tpm_read_log_of(struct tpm_chip *chip)
 	const u32 *sizep;
 	const u64 *basep;
 	struct tpm_bios_log *log;
+	u32 size;
+	u64 base;
 
 	log = &chip->log;
 	if (chip->dev.parent && chip->dev.parent->of_node)
@@ -41,18 +43,35 @@ int tpm_read_log_of(struct tpm_chip *chip)
 	if (sizep == NULL || basep == NULL)
 		return -EIO;
 
-	if (*sizep == 0) {
+	/*
+	 * For both vtpm/tpm, firmware has log addr and log size in big
+	 * endian format. But in case of vtpm, there is a method called
+	 * sml-handover which is run during kernel init even before
+	 * device tree is setup. This sml-handover function takes care
+	 * of endianness and writes to sml-base and sml-size in little
+	 * endian format. For this reason, vtpm doesn't need conversion
+	 * but physical tpm needs the conversion.
+	 */
+	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0) {
+		size = be32_to_cpup(sizep);
+		base = be64_to_cpup(basep);
+	} else {
+		size = *sizep;
+		base = *basep;
+	}
+
+	if (size == 0) {
 		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
 		return -EIO;
 	}
 
-	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
+	log->bios_event_log = kmalloc(size, GFP_KERNEL);
 	if (!log->bios_event_log)
 		return -ENOMEM;
 
-	log->bios_event_log_end = log->bios_event_log + *sizep;
+	log->bios_event_log_end = log->bios_event_log + size;
 
-	memcpy(log->bios_event_log, __va(*basep), *sizep);
+	memcpy(log->bios_event_log, __va(base), size);
 
 	return 0;
 }
-- 
2.5.0

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[PATCH v9 0/2] securityfs support for TPM 2.0 firmware event log  Nayna Jain <nayna@linux.vnet.ibm.com> - 2017-01-23 08:30 +0100
  [PATCH v9 2/2] tpm: add securityfs support for TPM 2.0 firmware event log Nayna Jain <nayna@linux.vnet.ibm.com> - 2017-01-23 08:30 +0100
    Re: [PATCH v9 2/2] tpm: add securityfs support for TPM 2.0 firmware  event log Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-01-23 16:20 +0100
      Re: [PATCH v9 2/2] tpm: add securityfs support for TPM 2.0 firmware  event log Nayna <nayna@linux.vnet.ibm.com> - 2017-01-24 11:20 +0100
        Re: [PATCH v9 2/2] tpm: add securityfs support for TPM 2.0 firmware  event log Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-01-25 14:40 +0100
  [PATCH v9 1/2] tpm: enhance read_log_of() to support Physical TPM event log Nayna Jain <nayna@linux.vnet.ibm.com> - 2017-01-23 08:30 +0100
  Re: [PATCH v9 0/2] securityfs support for TPM 2.0 firmware event log Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-01-23 16:10 +0100

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