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: Jiandi An <anjiandi@codeaurora.org>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> (on x86/PTT)
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index d520ac5..a3035220 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -136,7 +136,7 @@
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
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index d91e47d..72b03c3 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -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_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 @@
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 @@
*/
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 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 @@
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 @@
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 @@
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 @@
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;
