Commit 08eff49d authored by Jiandi An's avatar Jiandi An Committed by Jarkko Sakkinen
Browse files

tpm/tpm_crb: Enable TPM CRB interface for ARM64 



This enables TPM Command Response Buffer interface driver for
ARM64 and implements an ARM specific TPM CRB start method that
invokes a Secure Monitor Call (SMC) to request the TrustZone
Firmware to execute or cancel a TPM 2.0 command.

In ARM, TrustZone security extensions enable a secure software
environment with Secure Monitor mode.  A Secure Monitor Call
(SMC) is used to enter the Secure Monitor mode and perform a
Secure Monitor service to communicate with TrustZone firmware
which has control over the TPM hardware.

Signed-off-by: default avatarJiandi An <anjiandi@codeaurora.org>
Tested-by: default avatarShanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> (on x86/PTT)
Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
parent cf8252ca

drivers/char/tpm/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ config TCG_XEN 


config TCG_CRB

	tristate "TPM 2.0 CRB Interface"

	depends on X86 && ACPI

	depends on ACPI

	---help---

	  If you have a TPM security chip that is compliant with the

	  TCG CRB 2.0 TPM specification say Yes and it will be accessible

drivers/char/tpm/tpm_crb.c

+65 −2
Original line number Diff line number Diff line
@@ -20,6 +20,9 @@ 
#include <linux/rculist.h>

#include <linux/module.h>

#include <linux/pm_runtime.h>

#ifdef CONFIG_ARM64

#include <linux/arm-smccc.h>

#endif

#include "tpm.h"



#define ACPI_SIG_TPM2 "TPM2"
@@ -93,6 +96,7 @@ enum crb_status { 
enum crb_flags {

	CRB_FL_ACPI_START	= BIT(0),

	CRB_FL_CRB_START	= BIT(1),

	CRB_FL_CRB_SMC_START	= BIT(2),

};



struct crb_priv {
@@ -103,6 +107,15 @@ struct crb_priv { 
	u8 __iomem *cmd;

	u8 __iomem *rsp;

	u32 cmd_size;

	u32 smc_func_id;

};



struct tpm2_crb_smc {

	u32 interrupt;

	u8 interrupt_flags;

	u8 op_flags;

	u16 reserved2;

	u32 smc_func_id;

};



/**
@@ -122,7 +135,8 @@ struct crb_priv { 
 */

static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)

{

	if (priv->flags & CRB_FL_ACPI_START)

	if ((priv->flags & CRB_FL_ACPI_START) ||

	    (priv->flags & CRB_FL_CRB_SMC_START))

		return 0;



	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
@@ -167,7 +181,8 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value, 
static int __maybe_unused crb_cmd_ready(struct device *dev,

					struct crb_priv *priv)

{

	if (priv->flags & CRB_FL_ACPI_START)

	if ((priv->flags & CRB_FL_ACPI_START) ||

	    (priv->flags & CRB_FL_CRB_SMC_START))

		return 0;



	iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
@@ -262,6 +277,34 @@ static int crb_do_acpi_start(struct tpm_chip *chip) 
	return rc;

}



#ifdef CONFIG_ARM64

/*

 * This is a TPM Command Response Buffer start method that invokes a

 * Secure Monitor Call to requrest the firmware to execute or cancel

 * a TPM 2.0 command.

 */

static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)

{

	struct arm_smccc_res res;



	arm_smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);

	if (res.a0 != 0) {

		dev_err(dev,

			FW_BUG "tpm_crb_smc_start() returns res.a0 = 0x%lx\n",

			res.a0);

		return -EIO;

	}



	return 0;

}

#else

static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)

{

	dev_err(dev, FW_BUG "tpm_crb: incorrect start method\n");

	return -EINVAL;

}

#endif



static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)

{

	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
@@ -289,6 +332,11 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len) 
	if (priv->flags & CRB_FL_ACPI_START)

		rc = crb_do_acpi_start(chip);



	if (priv->flags & CRB_FL_CRB_SMC_START) {

		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);

		rc = tpm_crb_smc_start(&chip->dev, priv->smc_func_id);

	}



	return rc;

}
@@ -483,6 +531,7 @@ static int crb_acpi_add(struct acpi_device *device) 
	struct crb_priv *priv;

	struct tpm_chip *chip;

	struct device *dev = &device->dev;

	struct tpm2_crb_smc *crb_smc;

	acpi_status status;

	u32 sm;

	int rc;
@@ -515,6 +564,20 @@ static int crb_acpi_add(struct acpi_device *device) 
	    sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)

		priv->flags |= CRB_FL_ACPI_START;



	if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_SMC) {

		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_smc))) {

			dev_err(dev,

				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",

				buf->header.length,

				ACPI_TPM2_COMMAND_BUFFER_WITH_SMC);

			return -EINVAL;

		}

		crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf,

				       ACPI_TPM2_START_METHOD_PARAMETER_OFFSET);

		priv->smc_func_id = crb_smc->smc_func_id;

		priv->flags |= CRB_FL_CRB_SMC_START;

	}



	rc = crb_map_io(device, priv, buf);

	if (rc)

		return rc;

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