Re: [PATCH 7/8] tpm: Implement state command for Cr50

On Mon, Feb 28, 2022 at 05:11:24PM -0700, Simon Glass wrote:

Add a vendor-specific TPM2 command for this and implement it for Cr50.

Signed-off-by: Simon Glass sjg@chromium.org

drivers/tpm/cr50_i2c.c | 117 +++++++++++++++++++++++++++++++++++++++++ include/tpm-v2.h | 54 +++++++++++++++++++ lib/tpm-v2.c | 24 +++++++++ 3 files changed, 195 insertions(+)

diff --git a/drivers/tpm/cr50_i2c.c b/drivers/tpm/cr50_i2c.c index f8c3087894..dabf617be0 100644 --- a/drivers/tpm/cr50_i2c.c +++ b/drivers/tpm/cr50_i2c.c @@ -13,11 +13,13 @@ #include <irq.h> #include <log.h> #include <spl.h> +#include <tpm-common.h> #include <tpm-v2.h> #include <acpi/acpigen.h> #include <acpi/acpi_device.h> #include <asm/gpio.h> #include <asm/io.h> +#include <asm/unaligned.h> #include <linux/delay.h> #include <dm/acpi.h>

@@ -54,6 +56,41 @@ struct cr50_priv { bool use_irq; };

+/*

• • The below structure represents the body of the response to the 'report tpm
• • state' vendor command.
• • It is transferred over the wire, so it needs to be serialized/deserialized,
• • and it is likely to change, so its contents must be versioned.
• */

+#define TPM_STATE_VERSION 1 +struct tpm_vendor_state {

• u32 version;
• /*

• * The following three fields are set by the TPM in case of an assert.
  

• * There is no other processing than setting the source code line
  

• * number, error code and the first 4 characters of the function name.
  

• *
  

• * We don't expect this happening, but it is included in the report
  

• * just in case.
  

• */
  

• u32 fail_line; /* s_failLIne */
• u32 fail_code; /* s_failCode */
• char func_name[4]; /* s_failFunction, limited to 4 chars */
• /*

• * The following two fields are the current time filtered value of the
  

• * 'failed tries' TPM counter, and the maximum allowed value of the
  

• * counter.
  

• *
  

• * failed_tries == max_tries is the definition of the TPM lockout
  

• * condition.
  

• */
  

• u32 failed_tries; /* gp.failedTries */
• u32 max_tries; /* gp.maxTries */
• /* The below fields are present in version 2 and above */

+};

/* Wait for interrupt to indicate TPM is ready */ static int cr50_i2c_wait_tpm_ready(struct udevice *dev) { @@ -573,6 +610,85 @@ static int cr50_i2c_get_desc(struct udevice *dev, char *buf, int size) return len; }

+static int stringify_state(char *buf, int len, char *str, size_t max_size) +{

• struct tpm_vendor_state state;
• size_t text_size = 0;
• state.version = get_unaligned_be32(buf +

• offsetof(struct tpm_vendor_state, version));
  

• state.fail_line = get_unaligned_be32(buf +

• offsetof(struct tpm_vendor_state, fail_line));
  

• state.fail_code = get_unaligned_be32(buf +

• offsetof(struct tpm_vendor_state, fail_code));
  

• memcpy(state.func_name,

•       buf + offsetof(struct tpm_vendor_state, func_name),
  

•       sizeof(state.func_name));
  

• state.failed_tries = get_unaligned_be32(buf +

• offsetof(struct tpm_vendor_state, failed_tries));
  

• state.max_tries = get_unaligned_be32(buf +

• offsetof(struct tpm_vendor_state, max_tries));
  

• text_size += snprintf(str + text_size, max_size - text_size,

• 	      "v=%d", state.version);
  

• if (text_size >= max_size)

• return -ENOSPC;
  

• if (state.version > TPM_STATE_VERSION)

• text_size += snprintf(str + text_size,
  

• 		      max_size - text_size,
  

• 		      " not fully supported\n");
  

• if (text_size >= max_size)

• return -ENOSPC;
  

• if (state.version == 0)

• return -EINVAL;	/* This should never happen */
  

• text_size += snprintf(str + text_size,

• 	      max_size - text_size,
  

• 	      " failed_tries=%d max_tries=%d\n",
  

• 	      state.failed_tries, state.max_tries);
  

• if (text_size >= max_size)

• return -ENOSPC;
  

• if (state.fail_line) {

• /* make sure function name is zero terminated. */
  

• char func_name[sizeof(state.func_name) + 1];
  

• memcpy(func_name, state.func_name, sizeof(state.func_name));
  

• func_name[sizeof(state.func_name)] = '\0';
  

• text_size += snprintf(str + text_size,
  

• 		      max_size - text_size,
  

• 		      "tpm failed: f %s line %d code %d",
  

• 		      func_name,
  

• 		      state.fail_line,
  

• 		      state.fail_code);
  

• if (text_size >= max_size)
  

• 	return -ENOSPC;
  

• }
• return 0;

+}

Is this error state described in the TCG TIS specs ? If so we should plug this into the generic TPM API and the driver should only define cr50_i2c_report_state() etc

+static int cr50_i2c_report_state(struct udevice *dev, char *str, int str_max) +{

• char buf[50];
• int buf_size = sizeof(buf);
• int ret;
• ret = tpm2_cr50_report_state(dev, buf, &buf_size);
• if (ret)

• return ret;
  

• /* TPM responded as expected */
• ret = stringify_state(buf, buf_size, str, str_max);
• if (ret)

• return ret;
  

• return 0;

+}

[...]

Thanks /Ilias