[PATCH v3 6/7] tpm: Implement state command for Cr50
Ilias Apalodimas
ilias.apalodimas at linaro.org
Mon Aug 22 08:03:30 CEST 2022
Hi Simon,
This produces some build warnings e.g
drivers/tpm/cr50_i2c.c: In function ‘cr50_i2c_report_state’:
drivers/tpm/cr50_i2c.c:680:48: warning: passing argument 3 of
‘tpm2_cr50_report_state’ from incompatible pointer type
[-Wincompatible-pointer-types]
680 | ret = tpm2_cr50_report_state(dev, buf, &buf_size);
| ^~~~~~~~~
| |
| int *
On Fri, 19 Aug 2022 at 16:47, Simon Glass <sjg at chromium.org> wrote:
>
> 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>
> ---
>
> (no changes since v1)
>
> 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 f8c30878947..dabf617be0e 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;
> +}
> +
> +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;
> +}
> +
> static int cr50_i2c_open(struct udevice *dev)
> {
> char buf[80];
> @@ -730,6 +846,7 @@ 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..8e90a616220 100644
> --- a/include/tpm-v2.h
> +++ b/include/tpm-v2.h
> @@ -419,6 +419,50 @@ enum {
> HR_NV_INDEX = TPM_HT_NV_INDEX << HR_SHIFT,
> };
>
> +/*
> + * 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,
> +};
> +
> /**
> * Issue a TPM2_Startup command.
> *
> @@ -658,4 +702,14 @@ 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
> + * @recvbuf: Buffer to save the response to
> + * @recv_size: Pointer to the size of the response buffer
> + * Return: result of the operation
> + */
> +u32 tpm2_cr50_report_state(struct udevice *dev, u8 *recvbuf, size_t *recv_size);
> +
> #endif /* __TPM_V2_H */
> diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
> index 3e240bb4c67..3de4841974a 100644
> --- a/lib/tpm-v2.c
> +++ b/lib/tpm-v2.c
> @@ -679,3 +679,27 @@ u32 tpm2_submit_command(struct udevice *dev, const u8 *sendbuf,
> {
> return tpm_sendrecv_command(dev, sendbuf, recvbuf, recv_size);
> }
> +
> +u32 tpm2_cr50_report_state(struct udevice *dev, 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(TPM2_CR50_VENDOR_COMMAND), /* Command code */
> +
> + tpm_u16(TPM2_CR50_SUB_CMD_REPORT_TPM_STATE),
> + };
> + 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;
> +}
>From the previous patchset, I still don't understand why it makes
sense to add hardware specific functions in the generic API.
It doesn't seem too much work to move this into drivers/tpm/cr50_i2c.c
Thanks
/Ilias
> --
> 2.37.1.595.g718a3a8f04-goog
>
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