arch/arm64: Support calling a trusted monitor

Implement support for generating an SMC to call a trusted monitor. Some
functions are provided to read the SoC ID from the monitor, if
supported.

Change-Id: I158db0b971aba722b3995d52162146aa406d1644
Signed-off-by: Benjamin Doron <benjamin.doron@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78284
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/arch/arm64/Makefile.mk

@@ -30,6 +30,9 @@ bootblock-y += eabi_compat.c
 decompressor-$(CONFIG_ARM64_USE_ARCH_TIMER) += arch_timer.c
 bootblock-$(CONFIG_ARM64_USE_ARCH_TIMER) += arch_timer.c
 bootblock-y += transition.c transition_asm.S
+ifneq ($(CONFIG_ARM64_CURRENT_EL),3)
+bootblock-y += smc.c smc_asm.S
+endif
 
 decompressor-y += memset.S
 bootblock-y += memset.S
@@ -69,6 +72,9 @@ verstage-y += memcpy.S
 verstage-y += memmove.S
 
 verstage-y += transition.c transition_asm.S
+ifneq ($(CONFIG_ARM64_CURRENT_EL),3)
+verstage-y += smc.c smc_asm.S
+endif
 
 endif # CONFIG_ARCH_VERSTAGE_ARM64
 
@@ -88,6 +94,9 @@ romstage-y += memmove.S
 romstage-y += ramdetect.c
 romstage-y += romstage.c
 romstage-y += transition.c transition_asm.S
+ifneq ($(CONFIG_ARM64_CURRENT_EL),3)
+romstage-y += smc.c smc_asm.S
+endif
 
 rmodules_arm64-y += memset.S
 rmodules_arm64-y += memcpy.S
@@ -109,6 +118,7 @@ ifeq ($(CONFIG_ARCH_RAMSTAGE_ARM64),y)
 ramstage-y += div0.c
 ramstage-y += eabi_compat.c
 ramstage-y += boot.c
+ramstage-$(CONFIG_GENERATE_SMBIOS_TABLES) += smbios.c
 ramstage-y += tables.c
 ramstage-y += ramdetect.c
 ramstage-$(CONFIG_ARM64_USE_ARCH_TIMER) += arch_timer.c
@@ -117,6 +127,9 @@ ramstage-y += memcpy.S
 ramstage-y += memmove.S
 ramstage-$(CONFIG_ARM64_USE_ARM_TRUSTED_FIRMWARE) += bl31.c
 ramstage-y += transition.c transition_asm.S
+ifneq ($(CONFIG_ARM64_CURRENT_EL),3)
+ramstage-y += smc.c smc_asm.S
+endif
 ramstage-$(CONFIG_PAYLOAD_FIT_SUPPORT) += fit_payload.c
 ramstage-$(CONFIG_HAVE_ACPI_TABLES) += acpi.c
 ramstage-y += dma.c

src/arch/arm64/include/armv8/arch/smc.h

@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef ARM_ARM64_SMC_H
+#define ARM_ARM64_SMC_H
+
+#include <types.h>
+
+uint64_t smc(uint32_t function_id, uint64_t arg1, uint64_t arg2, uint64_t arg3,
+		uint64_t arg4, uint64_t arg5, uint64_t arg6, uint64_t arg7);
+
+#define smc_call0(function_id)			smc(function_id, 0, 0, 0, 0, 0, 0, 0)
+#define smc_call1(function_id, a1)		smc(function_id, a1, 0, 0, 0, 0, 0, 0)
+#define smc_call2(function_id, a1, a2)		smc(function_id, a1, a2, 0, 0, 0, 0, 0)
+#define smc_call3(function_id, a1, a2, a3)	smc(function_id, a1, a2, a3, 0, 0, 0, 0)
+
+/* Documented in https://developer.arm.com/documentation/den0022/ */
+enum psci_return_values {
+	PSCI_SUCCESS = 0,
+	PSCI_NOT_SUPPORTED = -1,
+	PSCI_INVALID_PARAMETERS = -2,
+	PSCI_DENIED = -3,
+	PSCI_ALREADY_ON = -4,
+	PSCI_ON_PENDING = -5,
+	PSCI_INTERNAL_FAILURE = -6,
+	PSCI_NOT_PRESENT = -7,
+	PSCI_DISABLED = -8,
+	PSCI_INVALID_ADDRESS = -9,
+};
+
+/* PSCI functions */
+#define PSCI_VERSION		0x84000000
+#define PSCI_FEATURES		0x8400000a
+
+/* Documented in https://developer.arm.com/documentation/den0028/ */
+enum smccc_return_values {
+	SMC_SUCCESS = 0,
+	SMC_NOT_SUPPORTED = -1,
+	SMC_NOT_REQUIRED = -2,
+	SMC_INVALID_PARAMETER = -3,
+};
+
+/* SMCCC functions */
+#define SMCCC_VERSION		0x80000000
+#define SMCCC_ARCH_FEATURES	0x80000001
+#define SMCCC_ARCH_SOC_ID	0x80000002
+#define  SMCCC_GET_SOC_VERSION	0
+#define  SMCCC_GET_SOC_REVISION	1
+
+uint8_t smccc_supports_arch_soc_id(void);
+enum cb_err smccc_arch_soc_id(uint32_t *jep106code, uint32_t *soc_revision);
+
+#endif /* ARM_ARM64_SMC_H */

src/arch/arm64/smc.c

@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/smc.h>
+#include <console/console.h>
+#include <types.h>
+
+/* Assumes at least a PSCI implementation is present */
+uint8_t smccc_supports_arch_soc_id(void)
+{
+	static uint8_t supported = 0xff;
+	uint64_t smc_ret;
+
+	if (supported != 0xff)
+		return supported;
+
+	// PSCI_FEATURES mandatory from PSCI 1.0
+	smc_ret = smc_call0(PSCI_VERSION);
+	if (smc_ret < 0x10000)
+		goto fail;
+
+	smc_ret = smc_call1(PSCI_FEATURES, SMCCC_VERSION);
+	if (smc_ret == PSCI_NOT_SUPPORTED)
+		goto fail;
+
+	// SMCCC_ARCH_FEATURES supported from SMCCC 1.1
+	smc_ret = smc_call0(SMCCC_VERSION);
+	if (smc_ret < 0x10001)
+		goto fail;
+
+	smc_ret = smc_call1(SMCCC_ARCH_FEATURES, SMCCC_ARCH_SOC_ID);
+	if (smc_ret != SMC_SUCCESS)
+		goto fail;
+
+	supported = 1;
+	return supported;
+
+fail:
+	supported = 0;
+	return supported;
+}
+
+enum cb_err smccc_arch_soc_id(uint32_t *jep106code, uint32_t *soc_revision)
+{
+	uint64_t smc_ret;
+
+	if (jep106code == NULL || soc_revision == NULL)
+		return CB_ERR_ARG;
+
+	smc_ret = smc_call1(SMCCC_ARCH_SOC_ID, SMCCC_GET_SOC_VERSION);
+	if (smc_ret != SMC_INVALID_PARAMETER)
+		*jep106code = smc_ret;
+	else
+		*jep106code = -1;
+
+	smc_ret = smc_call1(SMCCC_ARCH_SOC_ID, SMCCC_GET_SOC_REVISION);
+	if (smc_ret != SMC_INVALID_PARAMETER)
+		*soc_revision = smc_ret;
+	else
+		*soc_revision = -1;
+
+	if (*jep106code == -1 || *soc_revision == -1) {
+		printk(BIOS_ERR, "SMCCC_ARCH_SOC_ID failed!\n");
+		return CB_ERR;
+	} else
+		return CB_SUCCESS;
+}

src/arch/arm64/smc_asm.S

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/asm.h>
+
+ENTRY(smc)
+	/* W0, X1-X7 passed as arguments. Function ID is always W0. */
+	smc	#0
+	ret			/* X0 passed back as return value */
+ENDPROC(smc)