[PATCH v5 6/7] tpm: Implement state command for Cr50
Simon Glass
sjg at chromium.org
Wed Aug 31 05:05:37 CEST 2022
Add a vendor-specific TPM2 command for this and implement it for Cr50.
Note: This is not part of the TPM spec, but is a Cr50 extension.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v5:
- Use size_t for buffer size
Changes in v4:
- Rename function and add arguments for the command/subcmd
drivers/tpm/cr50_i2c.c | 163 +++++++++++++++++++++++++++++++++++++++++
include/tpm-v2.h | 13 ++++
lib/tpm-v2.c | 25 +++++++
3 files changed, 201 insertions(+)
diff --git a/drivers/tpm/cr50_i2c.c b/drivers/tpm/cr50_i2c.c
index f8c30878947..acf4c7859a9 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>
@@ -37,6 +39,50 @@ enum {
CR50_MAX_BUF_SIZE = 63,
};
+/*
+ * Operations specific to the Cr50 TPM used on Chromium OS and Android devices
+ *
+ * FIXME: below is not enough to differentiate between vendors commands
+ * of numerous devices. However, the current tpm2 APIs aren't very amenable
+ * to extending generically because the marshaling code is assuming all
+ * knowledge of all commands.
+ */
+#define TPM2_CC_VENDOR_BIT_MASK 0x20000000
+
+#define TPM2_CR50_VENDOR_COMMAND (TPM2_CC_VENDOR_BIT_MASK | 0)
+#define TPM2_CR50_SUB_CMD_IMMEDIATE_RESET 19
+#define TPM2_CR50_SUB_CMD_NVMEM_ENABLE_COMMITS 21
+#define TPM2_CR50_SUB_CMD_REPORT_TPM_STATE 23
+#define TPM2_CR50_SUB_CMD_TURN_UPDATE_ON 24
+#define TPM2_CR50_SUB_CMD_GET_REC_BTN 29
+#define TPM2_CR50_SUB_CMD_TPM_MODE 40
+#define TPM2_CR50_SUB_CMD_GET_BOOT_MODE 52
+#define TPM2_CR50_SUB_CMD_RESET_EC 53
+
+/* Cr50 vendor-specific error codes. */
+#define VENDOR_RC_ERR 0x00000500
+enum cr50_vendor_rc {
+ VENDOR_RC_INTERNAL_ERROR = (VENDOR_RC_ERR | 6),
+ VENDOR_RC_NO_SUCH_SUBCOMMAND = (VENDOR_RC_ERR | 8),
+ VENDOR_RC_NO_SUCH_COMMAND = (VENDOR_RC_ERR | 127),
+};
+
+enum cr50_tpm_mode {
+ /*
+ * Default state: TPM is enabled, and may be set to either
+ * TPM_MODE_ENABLED or TPM_MODE_DISABLED.
+ */
+ TPM_MODE_ENABLED_TENTATIVE = 0,
+
+ /* TPM is enabled, and mode may not be changed. */
+ TPM_MODE_ENABLED = 1,
+
+ /* TPM is disabled, and mode may not be changed. */
+ TPM_MODE_DISABLED = 2,
+
+ TPM_MODE_INVALID,
+};
+
/**
* struct cr50_priv - Private driver data
*
@@ -54,6 +100,41 @@ 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 +654,87 @@ 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;
+}
+
+static int cr50_i2c_report_state(struct udevice *dev, char *str, int str_max)
+{
+ char buf[50];
+ size_t buf_size = sizeof(buf);
+ int ret;
+
+ ret = tpm2_report_state(dev, TPM2_CR50_VENDOR_COMMAND,
+ TPM2_CR50_SUB_CMD_REPORT_TPM_STATE,
+ 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;
+}
+
static int cr50_i2c_open(struct udevice *dev)
{
char buf[80];
@@ -730,6 +892,7 @@ struct acpi_ops cr50_acpi_ops = {
static const struct tpm_ops cr50_i2c_ops = {
.open = cr50_i2c_open,
.get_desc = cr50_i2c_get_desc,
+ .report_state = cr50_i2c_report_state,
.send = cr50_i2c_send,
.recv = cr50_i2c_recv,
.cleanup = cr50_i2c_cleanup,
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index e79c90b9395..36c6ac0be6e 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -658,4 +658,17 @@ u32 tpm2_disable_platform_hierarchy(struct udevice *dev);
u32 tpm2_submit_command(struct udevice *dev, const u8 *sendbuf,
u8 *recvbuf, size_t *recv_size);
+/**
+ * tpm_cr50_report_state() - Report the Cr50 internal state
+ *
+ * @dev: TPM device
+ * @vendor_cmd: Vendor command number to send
+ * @vendor_subcmd: Vendor sub-command number to send
+ * @recvbuf: Buffer to save the response to
+ * @recv_size: Pointer to the size of the response buffer
+ * Return: result of the operation
+ */
+u32 tpm2_report_state(struct udevice *dev, uint vendor_cmd, uint vendor_subcmd,
+ u8 *recvbuf, size_t *recv_size);
+
#endif /* __TPM_V2_H */
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 3e240bb4c67..edee9854a7c 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -679,3 +679,28 @@ u32 tpm2_submit_command(struct udevice *dev, const u8 *sendbuf,
{
return tpm_sendrecv_command(dev, sendbuf, recvbuf, recv_size);
}
+
+u32 tpm2_report_state(struct udevice *dev, uint vendor_cmd, uint vendor_subcmd,
+ u8 *recvbuf, size_t *recv_size)
+{
+ u8 command_v2[COMMAND_BUFFER_SIZE] = {
+ /* header 10 bytes */
+ tpm_u16(TPM2_ST_NO_SESSIONS), /* TAG */
+ tpm_u32(10 + 2), /* Length */
+ tpm_u32(vendor_cmd), /* Command code */
+
+ tpm_u16(vendor_subcmd),
+ };
+ int ret;
+
+ ret = tpm_sendrecv_command(dev, command_v2, recvbuf, recv_size);
+ log_debug("ret=%s, %x\n", dev->name, ret);
+ if (ret)
+ return ret;
+ if (*recv_size < 12)
+ return -ENODATA;
+ *recv_size -= 12;
+ memcpy(recvbuf, recvbuf + 12, *recv_size);
+
+ return 0;
+}
--
2.37.2.672.g94769d06f0-goog
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