feat(services): add a SPD for ProvenCore

Adds a dispatcher for ProvenCore based on the test secure payload
dispatcher.

Signed-off-by: Florian Lugou <florian.lugou@provenrun.com>
Change-Id: I978afc3af6a6f65791655685a7bc80070673c9f3

10 files changed, 806 insertions, 2 deletions

diff --git a/docs/about/features.rst b/docs/about/features.rst
index 4b7fbe56b..cb8b5527a 100644
--- a/docs/about/features.rst
+++ b/docs/about/features.rst
@@ -46,8 +46,8 @@ Current features
 -  A Test SP and SPD to demonstrate AArch64 Secure Monitor functionality and SP
    interaction with PSCI.
 
--  SPDs for the `OP-TEE Secure OS`_, `NVIDIA Trusted Little Kernel`_
-   and `Trusty Secure OS`_.
+-  SPDs for the `OP-TEE Secure OS`_, `NVIDIA Trusted Little Kernel`_,
+   `Trusty Secure OS`_ and `ProvenCore Secure OS`_.
 
 -  A Trusted Board Boot implementation, conforming to all mandatory TBBR
    requirements. This includes image authentication, Firmware Update (or
@@ -121,6 +121,7 @@ Still to come
 .. _OP-TEE Secure OS: https://github.com/OP-TEE/optee_os
 .. _NVIDIA Trusted Little Kernel: http://nv-tegra.nvidia.com/gitweb/?p=3rdparty/ote_partner/tlk.git;a=summary
 .. _Trusty Secure OS: https://source.android.com/security/trusty
+.. _ProvenCore Secure OS: https://provenrun.com/products/provencore/
 
 --------------
 
diff --git a/docs/about/maintainers.rst b/docs/about/maintainers.rst
index 96a052304..d86bd8aa4 100644
--- a/docs/about/maintainers.rst
+++ b/docs/about/maintainers.rst
@@ -772,6 +772,13 @@ Test Secure Payload (TSP)
 :|F|: bl32/tsp/
 :|F|: services/spd/tspd/
 
+ProvenCore Secure Payload Dispatcher
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+:|M|: Jérémie Corbier <jeremie.corbier@provenrun.com>
+:|G|: `jcorbier`_
+:|F|: docs/components/spd/pnc-dispatcher.rst
+:|F|: services/spd/pncd/
+
 Tools
 ~~~~~
 
@@ -842,6 +849,7 @@ Conventional Changelog Extensions
 .. _grandpaul: https://github.com/grandpaul
 .. _hzhuang1: https://github.com/hzhuang1
 .. _JackyBai: https://github.com/JackyBai
+.. _jcorbier: https://github.com/jcorbier
 .. _jenswi-linaro: https://github.com/jenswi-linaro
 .. _jwerner-chromium: https://github.com/jwerner-chromium
 .. _kostapr: https://github.com/kostapr
diff --git a/docs/components/spd/index.rst b/docs/components/spd/index.rst
index 25d0124b1..6857806c2 100644
--- a/docs/components/spd/index.rst
+++ b/docs/components/spd/index.rst
@@ -8,3 +8,4 @@ Secure Payload Dispatcher (SPD)
    optee-dispatcher
    tlk-dispatcher
    trusty-dispatcher
+   pnc-dispatcher
diff --git a/docs/components/spd/pnc-dispatcher.rst b/docs/components/spd/pnc-dispatcher.rst
new file mode 100644
index 000000000..5be2fc7dc
--- /dev/null
+++ b/docs/components/spd/pnc-dispatcher.rst
@@ -0,0 +1,10 @@
+ProvenCore Dispatcher
+=====================
+
+ProvenCore dispatcher (PnC-D) adds support for ProvenRun's ProvenCore micro-kernel
+to work with Trusted Firmware-A (TF-A).
+
+ProvenCore is a secure OS developed by ProvenRun S.A.S. using deductive formal methods.
+
+Once a BL32 is ready, PnC-D can be included in the image by adding "SPD=pncd"
+to the build command.
diff --git a/include/bl32/pnc/pnc.h b/include/bl32/pnc/pnc.h
new file mode 100644
index 000000000..03a32147a
--- /dev/null
+++ b/include/bl32/pnc/pnc.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __PNC_H__
+#define __PNC_H__
+
+#define SMC_YIELD		0xbf000000
+#define SMC_ACTION_FROM_S	0xbf000001
+#define SMC_GET_SHAREDMEM	0xbf000002
+#define SMC_CONFIG_SHAREDMEM	0xbf000003
+#define SMC_ACTION_FROM_NS	0xbf000004
+
+#ifndef __ASSEMBLER__
+
+#include <stdint.h>
+
+void *pncd_context_switch_to(unsigned long security_state);
+int plat_pncd_setup(void);
+uintptr_t plat_pncd_smc_handler(uint32_t smc_fid, u_register_t x1,
+				u_register_t x2, u_register_t x3,
+				u_register_t x4, void *cookie, void *handle,
+				u_register_t flags);
+
+#endif /* __ASSEMBLER__ */
+
+#endif /* __PNC_H__ */
diff --git a/services/spd/pncd/pncd.mk b/services/spd/pncd/pncd.mk
new file mode 100644
index 000000000..0f8eb2514
--- /dev/null
+++ b/services/spd/pncd/pncd.mk
@@ -0,0 +1,24 @@
+# Copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+PNCD_DIR		:=	services/spd/pncd
+SPD_INCLUDES		:=	-Iinclude/bl32/pnc
+SPD_INCLUDES		+=	-Iinclude/common/
+
+SPD_SOURCES		:=	services/spd/pncd/pncd_common.c		\
+				services/spd/pncd/pncd_helpers.S	\
+				services/spd/pncd/pncd_main.c
+
+NEED_BL32		:=	yes
+
+# The following constants need to be defined:
+#   - SPD_PNCD_NS_IRQ: IRQ number used to notify NS world when SMC_ACTION_FROM_S is received
+#   - SPD_PNCD_S_IRQ: IRQ number used to notify S world when SMC_ACTION_FROM_NS is received
+$(eval $(call assert_numerics, SPD_PNCD_NS_IRQ SPD_PNCD_S_IRQ))
+
+$(eval $(call add_defines,\
+    $(sort \
+        SPD_PNCD_NS_IRQ \
+        SPD_PNCD_S_IRQ \
+)))
diff --git a/services/spd/pncd/pncd_common.c b/services/spd/pncd/pncd_common.c
new file mode 100644
index 000000000..6fdb6293f
--- /dev/null
+++ b/services/spd/pncd/pncd_common.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <string.h>
+
+#include <arch_helpers.h>
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <lib/el3_runtime/context_mgmt.h>
+#include <lib/utils.h>
+#include <plat/common/platform.h>
+
+#include "pncd_private.h"
+
+/*******************************************************************************
+ * Given a secure payload entrypoint info pointer, entry point PC & pointer to a
+ * context data structure, this function will initialize pnc context and entry
+ * point info for the secure payload
+ ******************************************************************************/
+void pncd_init_pnc_ep_state(struct entry_point_info *pnc_entry_point,
+				uint64_t pc,
+				pnc_context_t *pnc_ctx)
+{
+	uint32_t ep_attr;
+
+	/* Passing a NULL context is a critical programming error */
+	assert(pnc_ctx);
+	assert(pnc_entry_point);
+	assert(pc);
+
+	/* Associate this context with the current cpu */
+	pnc_ctx->mpidr = read_mpidr();
+
+	cm_set_context(&pnc_ctx->cpu_ctx, SECURE);
+
+	/* initialise an entrypoint to set up the CPU context */
+	ep_attr = SECURE | EP_ST_ENABLE;
+	if (read_sctlr_el3() & SCTLR_EE_BIT) {
+		ep_attr |= EP_EE_BIG;
+	}
+	SET_PARAM_HEAD(pnc_entry_point, PARAM_EP, VERSION_1, ep_attr);
+
+	pnc_entry_point->pc = pc;
+	pnc_entry_point->spsr = SPSR_64(MODE_EL1,
+					MODE_SP_ELX,
+					DISABLE_ALL_EXCEPTIONS);
+	memset(&pnc_entry_point->args, 0, sizeof(pnc_entry_point->args));
+}
+
+/*******************************************************************************
+ * This function takes an SP context pointer and:
+ * 1. Applies the S-EL1 system register context from pnc_ctx->cpu_ctx.
+ * 2. Saves the current C runtime state (callee saved registers) on the stack
+ *    frame and saves a reference to this state.
+ * 3. Calls el3_exit() so that the EL3 system and general purpose registers
+ *    from the pnc_ctx->cpu_ctx are used to enter the secure payload image.
+ ******************************************************************************/
+uint64_t pncd_synchronous_sp_entry(pnc_context_t *pnc_ctx)
+{
+	assert(pnc_ctx != NULL);
+	assert(pnc_ctx->c_rt_ctx == 0U);
+
+	/* Apply the Secure EL1 system register context and switch to it */
+	assert(cm_get_context(SECURE) == &pnc_ctx->cpu_ctx);
+	cm_el1_sysregs_context_restore(SECURE);
+#if CTX_INCLUDE_FPREGS
+	fpregs_context_restore(get_fpregs_ctx(cm_get_context(SECURE)));
+#endif
+	cm_set_next_eret_context(SECURE);
+
+	return pncd_enter_sp(&pnc_ctx->c_rt_ctx);
+}
+
+
+/*******************************************************************************
+ * This function takes an SP context pointer and:
+ * 1. Saves the S-EL1 system register context tp pnc_ctx->cpu_ctx.
+ * 2. Restores the current C runtime state (callee saved registers) from the
+ *    stack frame using the reference to this state saved in pncd_enter_sp().
+ * 3. It does not need to save any general purpose or EL3 system register state
+ *    as the generic smc entry routine should have saved those.
+ ******************************************************************************/
+void pncd_synchronous_sp_exit(pnc_context_t *pnc_ctx, uint64_t ret)
+{
+	assert(pnc_ctx != NULL);
+	/* Save the Secure EL1 system register context */
+	assert(cm_get_context(SECURE) == &pnc_ctx->cpu_ctx);
+	cm_el1_sysregs_context_save(SECURE);
+#if CTX_INCLUDE_FPREGS
+	fpregs_context_save(get_fpregs_ctx(cm_get_context(SECURE)));
+#endif
+
+	assert(pnc_ctx->c_rt_ctx != 0);
+	pncd_exit_sp(pnc_ctx->c_rt_ctx, ret);
+
+	/* Should never reach here */
+	panic();
+}
diff --git a/services/spd/pncd/pncd_helpers.S b/services/spd/pncd/pncd_helpers.S
new file mode 100644
index 000000000..736b30f95
--- /dev/null
+++ b/services/spd/pncd/pncd_helpers.S
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include "pncd_private.h"
+
+	.global	pncd_enter_sp
+	/* ---------------------------------------------
+	 * This function is called with SP_EL0 as stack.
+	 * Here we stash our EL3 callee-saved registers
+	 * on to the stack as a part of saving the C
+	 * runtime and enter the secure payload.
+	 * 'x0' contains a pointer to the memory where
+	 * the address of the C runtime context is to be
+	 * saved.
+	 * ---------------------------------------------
+	 */
+func pncd_enter_sp
+	/* Make space for the registers that we're going to save */
+	mov	x3, sp
+	str	x3, [x0, #0]
+	sub	sp, sp, #PNCD_C_RT_CTX_SIZE
+
+	/* Save callee-saved registers on to the stack */
+	stp	x19, x20, [sp, #PNCD_C_RT_CTX_X19]
+	stp	x21, x22, [sp, #PNCD_C_RT_CTX_X21]
+	stp	x23, x24, [sp, #PNCD_C_RT_CTX_X23]
+	stp	x25, x26, [sp, #PNCD_C_RT_CTX_X25]
+	stp	x27, x28, [sp, #PNCD_C_RT_CTX_X27]
+	stp	x29, x30, [sp, #PNCD_C_RT_CTX_X29]
+
+	/* ---------------------------------------------
+	 * Everything is setup now. el3_exit() will
+	 * use the secure context to restore to the
+	 * general purpose and EL3 system registers to
+	 * ERET into the secure payload.
+	 * ---------------------------------------------
+	 */
+	b	el3_exit
+endfunc pncd_enter_sp
+
+	/* ---------------------------------------------
+	 * This function is called 'x0' pointing to a C
+	 * runtime context saved in pncd_enter_sp(). It
+	 * restores the saved registers and jumps to
+	 * that runtime with 'x0' as the new sp. This
+	 * destroys the C runtime context that had been
+	 * built on the stack below the saved context by
+	 * the caller. Later the second parameter 'x1'
+	 * is passed as return value to the caller
+	 * ---------------------------------------------
+	 */
+	.global pncd_exit_sp
+func pncd_exit_sp
+	/* Restore the previous stack */
+	mov	sp, x0
+
+	/* Restore callee-saved registers on to the stack */
+	ldp	x19, x20, [x0, #(PNCD_C_RT_CTX_X19 - PNCD_C_RT_CTX_SIZE)]
+	ldp	x21, x22, [x0, #(PNCD_C_RT_CTX_X21 - PNCD_C_RT_CTX_SIZE)]
+	ldp	x23, x24, [x0, #(PNCD_C_RT_CTX_X23 - PNCD_C_RT_CTX_SIZE)]
+	ldp	x25, x26, [x0, #(PNCD_C_RT_CTX_X25 - PNCD_C_RT_CTX_SIZE)]
+	ldp	x27, x28, [x0, #(PNCD_C_RT_CTX_X27 - PNCD_C_RT_CTX_SIZE)]
+	ldp	x29, x30, [x0, #(PNCD_C_RT_CTX_X29 - PNCD_C_RT_CTX_SIZE)]
+
+	/* ---------------------------------------------
+	 * This should take us back to the instruction
+	 * after the call to the last pncd_enter_sp().
+	 * Place the second parameter to x0 so that the
+	 * caller will see it as a return value from the
+	 * original entry call
+	 * ---------------------------------------------
+	 */
+	mov	x0, x1
+	ret
+endfunc pncd_exit_sp
diff --git a/services/spd/pncd/pncd_main.c b/services/spd/pncd/pncd_main.c
new file mode 100644
index 000000000..99c4aa1b2
--- /dev/null
+++ b/services/spd/pncd/pncd_main.c
@@ -0,0 +1,471 @@
+/*
+ * Copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/*******************************************************************************
+ * This is the Secure Payload Dispatcher (SPD). The dispatcher is meant to be a
+ * plug-in component to the Secure Monitor, registered as a runtime service. The
+ * SPD is expected to be a functional extension of the Secure Payload (SP) that
+ * executes in Secure EL1. The Secure Monitor will delegate all SMCs targeting
+ * the Trusted OS/Applications range to the dispatcher. The SPD will either
+ * handle the request locally or delegate it to the Secure Payload. It is also
+ * responsible for initialising and maintaining communication with the SP.
+ ******************************************************************************/
+
+#include <assert.h>
+#include <errno.h>
+#include <stddef.h>
+#include <string.h>
+
+#include <arch_helpers.h>
+#include <bl31/bl31.h>
+#include <bl31/interrupt_mgmt.h>
+#include <bl_common.h>
+#include <common/debug.h>
+#include <common/ep_info.h>
+#include <drivers/arm/gic_common.h>
+#include <lib/el3_runtime/context_mgmt.h>
+#include <lib/spinlock.h>
+#include <plat/common/platform.h>
+#include <pnc.h>
+#include "pncd_private.h"
+#include <runtime_svc.h>
+#include <tools_share/uuid.h>
+
+/*******************************************************************************
+ * Structure to keep track of ProvenCore state
+ ******************************************************************************/
+static pnc_context_t pncd_sp_context;
+
+static bool ree_info;
+static uint64_t ree_base_addr;
+static uint64_t ree_length;
+static uint64_t ree_tag;
+
+static bool pnc_initialized;
+
+static spinlock_t smc_handler_lock;
+
+static int pncd_init(void);
+
+static void context_save(unsigned long security_state)
+{
+	assert(sec_state_is_valid(security_state));
+
+	cm_el1_sysregs_context_save((uint32_t) security_state);
+#if CTX_INCLUDE_FPREGS
+	fpregs_context_save(get_fpregs_ctx(cm_get_context(security_state)));
+#endif
+}
+
+static void *context_restore(unsigned long security_state)
+{
+	void *handle;
+
+	assert(sec_state_is_valid(security_state));
+
+	/* Get a reference to the next context */
+	handle = cm_get_context((uint32_t) security_state);
+	assert(handle);
+
+	/* Restore state */
+	cm_el1_sysregs_context_restore((uint32_t) security_state);
+#if CTX_INCLUDE_FPREGS
+	fpregs_context_restore(get_fpregs_ctx(cm_get_context(security_state)));
+#endif
+
+	cm_set_next_eret_context((uint32_t) security_state);
+
+	return handle;
+}
+
+static uint64_t pncd_sel1_interrupt_handler(uint32_t id,
+		uint32_t flags, void *handle, void *cookie);
+
+/*******************************************************************************
+ * Switch context to the specified security state and return the targeted
+ * handle. Note that the context may remain unchanged if the switch is not
+ * allowed.
+ ******************************************************************************/
+void *pncd_context_switch_to(unsigned long security_state)
+{
+	unsigned long sec_state_from =
+	    security_state == SECURE ? NON_SECURE : SECURE;
+
+	assert(sec_state_is_valid(security_state));
+
+	/* Check if this is the first world switch */
+	if (!pnc_initialized) {
+		int rc;
+		uint32_t flags;
+
+		assert(sec_state_from == SECURE);
+
+		INFO("PnC initialization done\n");
+
+		/*
+		 * Register an interrupt handler for S-EL1 interrupts
+		 * when generated during code executing in the
+		 * non-secure state.
+		 */
+		flags = 0U;
+		set_interrupt_rm_flag(flags, NON_SECURE);
+		rc = register_interrupt_type_handler(INTR_TYPE_S_EL1,
+				pncd_sel1_interrupt_handler,
+				flags);
+		if (rc != 0) {
+			ERROR("Failed to register S-EL1 interrupt handler (%d)\n",
+			      rc);
+			panic();
+		}
+
+		context_save(SECURE);
+
+		pnc_initialized = true;
+
+		/*
+		 * Release the lock before restoring the EL3 context to
+		 * bl31_main.
+		 */
+		spin_unlock(&smc_handler_lock);
+
+		/*
+		 * SP reports completion. The SPD must have initiated
+		 * the original request through a synchronous entry
+		 * into the SP. Jump back to the original C runtime
+		 * context.
+		 */
+		pncd_synchronous_sp_exit(&pncd_sp_context, (uint64_t) 0x0);
+
+		/* Unreachable */
+		ERROR("Returned from pncd_synchronous_sp_exit... Should not happen\n");
+		panic();
+	}
+
+	/* Check that the world switch is allowed */
+	if (read_mpidr() != pncd_sp_context.mpidr) {
+		if (sec_state_from == SECURE) {
+			/*
+			 * Secure -> Non-Secure world switch initiated on a CPU where there
+			 * should be no Trusted OS running
+			 */
+			WARN("Secure to Non-Secure switch requested on CPU where ProvenCore is not supposed to be running...\n");
+		}
+
+		/*
+		 * Secure or Non-Secure world wants to switch world but there is no Secure
+		 * software on this core
+		 */
+		return cm_get_context((uint32_t) sec_state_from);
+	}
+
+	context_save(sec_state_from);
+
+	return context_restore(security_state);
+}
+
+/*******************************************************************************
+ * This function is the handler registered for S-EL1 interrupts by the PNCD. It
+ * validates the interrupt and upon success arranges entry into the PNC at
+ * 'pnc_sel1_intr_entry()' for handling the interrupt.
+ ******************************************************************************/
+static uint64_t pncd_sel1_interrupt_handler(uint32_t id,
+		uint32_t flags,
+		void *handle,
+		void *cookie)
+{
+	/* Check the security state when the exception was generated */
+	assert(get_interrupt_src_ss(flags) == NON_SECURE);
+
+	/* Sanity check the pointer to this cpu's context */
+	assert(handle == cm_get_context(NON_SECURE));
+
+	/* switch to PnC */
+	handle = pncd_context_switch_to(SECURE);
+
+	assert(handle != NULL);
+
+	SMC_RET0(handle);
+}
+
+#pragma weak plat_pncd_setup
+int plat_pncd_setup(void)
+{
+	return 0;
+}
+
+/*******************************************************************************
+ * Secure Payload Dispatcher setup. The SPD finds out the SP entrypoint and type
+ * (aarch32/aarch64) if not already known and initialises the context for entry
+ * into the SP for its initialisation.
+ ******************************************************************************/
+static int pncd_setup(void)
+{
+	entry_point_info_t *pnc_ep_info;
+
+	/*
+	 * Get information about the Secure Payload (BL32) image. Its
+	 * absence is a critical failure.
+	 *
+	 * TODO: Add support to conditionally include the SPD service
+	 */
+	pnc_ep_info = bl31_plat_get_next_image_ep_info(SECURE);
+	if (!pnc_ep_info) {
+		WARN("No PNC provided by BL2 boot loader, Booting device without PNC initialization. SMC`s destined for PNC will return SMC_UNK\n");
+		return 1;
+	}
+
+	/*
+	 * If there's no valid entry point for SP, we return a non-zero value
+	 * signalling failure initializing the service. We bail out without
+	 * registering any handlers
+	 */
+	if (!pnc_ep_info->pc) {
+		return 1;
+	}
+
+	pncd_init_pnc_ep_state(pnc_ep_info,
+			pnc_ep_info->pc,
+			&pncd_sp_context);
+
+	/*
+	 * All PNCD initialization done. Now register our init function with
+	 * BL31 for deferred invocation
+	 */
+	bl31_register_bl32_init(&pncd_init);
+	bl31_set_next_image_type(NON_SECURE);
+
+	return plat_pncd_setup();
+}
+
+/*******************************************************************************
+ * This function passes control to the Secure Payload image (BL32) for the first
+ * time on the primary cpu after a cold boot. It assumes that a valid secure
+ * context has already been created by pncd_setup() which can be directly used.
+ * It also assumes that a valid non-secure context has been initialised by PSCI
+ * so it does not need to save and restore any non-secure state. This function
+ * performs a synchronous entry into the Secure payload. The SP passes control
+ * back to this routine through a SMC.
+ ******************************************************************************/
+static int32_t pncd_init(void)
+{
+	entry_point_info_t *pnc_entry_point;
+	uint64_t rc = 0;
+
+	/*
+	 * Get information about the Secure Payload (BL32) image. Its
+	 * absence is a critical failure.
+	 */
+	pnc_entry_point = bl31_plat_get_next_image_ep_info(SECURE);
+	assert(pnc_entry_point);
+
+	cm_init_my_context(pnc_entry_point);
+
+	/*
+	 * Arrange for an entry into the test secure payload. It will be
+	 * returned via PNC_ENTRY_DONE case
+	 */
+	rc = pncd_synchronous_sp_entry(&pncd_sp_context);
+
+	/*
+	 * If everything went well at this point, the return value should be 0.
+	 */
+	return rc == 0;
+}
+
+#pragma weak plat_pncd_smc_handler
+/*******************************************************************************
+ * This function is responsible for handling the platform-specific SMCs in the
+ * Trusted OS/App range as defined in the SMC Calling Convention Document.
+ ******************************************************************************/
+uintptr_t plat_pncd_smc_handler(uint32_t smc_fid,
+		u_register_t x1,
+		u_register_t x2,
+		u_register_t x3,
+		u_register_t x4,
+		void *cookie,
+		void *handle,
+		u_register_t flags)
+{
+	(void) smc_fid;
+	(void) x1;
+	(void) x2;
+	(void) x3;
+	(void) x4;
+	(void) cookie;
+	(void) flags;
+
+	SMC_RET1(handle, SMC_UNK);
+}
+
+/*******************************************************************************
+ * This function is responsible for handling all SMCs in the Trusted OS/App
+ * range as defined in the SMC Calling Convention Document. It is also
+ * responsible for communicating with the Secure payload to delegate work and
+ * return results back to the non-secure state. Lastly it will also return any
+ * information that the secure payload needs to do the work assigned to it.
+ *
+ * It should only be called with the smc_handler_lock held.
+ ******************************************************************************/
+static uintptr_t pncd_smc_handler_unsafe(uint32_t smc_fid,
+		u_register_t x1,
+		u_register_t x2,
+		u_register_t x3,
+		u_register_t x4,
+		void *cookie,
+		void *handle,
+		u_register_t flags)
+{
+	uint32_t ns;
+
+	/* Determine which security state this SMC originated from */
+	ns = is_caller_non_secure(flags);
+
+	assert(ns != 0 || read_mpidr() == pncd_sp_context.mpidr);
+
+	switch (smc_fid) {
+	case SMC_CONFIG_SHAREDMEM:
+		if (ree_info) {
+			/* Do not Yield */
+			SMC_RET0(handle);
+		}
+
+		/*
+		 * Fetch the physical base address (x1) and size (x2) of the
+		 * shared memory allocated by the Non-Secure world. This memory
+		 * will be used by PNC to communicate with the Non-Secure world.
+		 * Verifying the validity of these values is up to the Trusted
+		 * OS.
+		 */
+		ree_base_addr = x1 | (x2 << 32);
+		ree_length = x3;
+		ree_tag = x4;
+
+		INFO("IN SMC_CONFIG_SHAREDMEM: addr=%lx, length=%lx, tag=%lx\n",
+		     (unsigned long) ree_base_addr,
+		     (unsigned long) ree_length,
+		     (unsigned long) ree_tag);
+
+		if ((ree_base_addr % 0x200000) != 0) {
+			SMC_RET1(handle, SMC_UNK);
+		}
+
+		if ((ree_length % 0x200000) != 0) {
+			SMC_RET1(handle, SMC_UNK);
+		}
+
+		ree_info = true;
+
+		/* Do not Yield */
+		SMC_RET4(handle, 0, 0, 0, 0);
+
+		break;
+
+	case SMC_GET_SHAREDMEM:
+		if (ree_info) {
+			x1 = (1U << 16) | ree_tag;
+			x2 = ree_base_addr & 0xFFFFFFFF;
+			x3 = (ree_base_addr >> 32) & 0xFFFFFFFF;
+			x4 = ree_length & 0xFFFFFFFF;
+			SMC_RET4(handle, x1, x2, x3, x4);
+		} else {
+			SMC_RET4(handle, 0, 0, 0, 0);
+		}
+
+		break;
+
+	case SMC_ACTION_FROM_NS:
+		if (ns == 0) {
+			SMC_RET1(handle, SMC_UNK);
+		}
+
+		if (SPD_PNCD_S_IRQ < MIN_PPI_ID) {
+			plat_ic_raise_s_el1_sgi(SPD_PNCD_S_IRQ,
+						pncd_sp_context.mpidr);
+		} else {
+			plat_ic_set_interrupt_pending(SPD_PNCD_S_IRQ);
+		}
+
+		SMC_RET0(handle);
+
+		break;
+
+	case SMC_ACTION_FROM_S:
+		if (ns != 0) {
+			SMC_RET1(handle, SMC_UNK);
+		}
+
+		if (SPD_PNCD_NS_IRQ < MIN_PPI_ID) {
+			/*
+			 * NS SGI is sent to the same core as the one running
+			 * PNC
+			 */
+			plat_ic_raise_ns_sgi(SPD_PNCD_NS_IRQ, read_mpidr());
+		} else {
+			plat_ic_set_interrupt_pending(SPD_PNCD_NS_IRQ);
+		}
+
+		SMC_RET0(handle);
+
+		break;
+
+	case SMC_YIELD:
+		assert(handle == cm_get_context(ns != 0 ? NON_SECURE : SECURE));
+		handle = pncd_context_switch_to(ns != 0 ? SECURE : NON_SECURE);
+
+		assert(handle != NULL);
+
+		SMC_RET0(handle);
+
+		break;
+
+	default:
+		INFO("Unknown smc: %x\n", smc_fid);
+		break;
+	}
+
+	return plat_pncd_smc_handler(smc_fid, x1, x2, x3, x4,
+				     cookie, handle, flags);
+}
+
+static uintptr_t pncd_smc_handler(uint32_t smc_fid,
+		u_register_t x1,
+		u_register_t x2,
+		u_register_t x3,
+		u_register_t x4,
+		void *cookie,
+		void *handle,
+		u_register_t flags)
+{
+	uintptr_t ret;
+
+	/* SMC handling is serialized */
+	spin_lock(&smc_handler_lock);
+	ret = pncd_smc_handler_unsafe(smc_fid, x1, x2, x3, x4, cookie, handle,
+								  flags);
+	spin_unlock(&smc_handler_lock);
+
+	return ret;
+}
+
+/* Define a SPD runtime service descriptor for fast SMC calls */
+DECLARE_RT_SVC(
+	pncd_fast,
+	OEN_TOS_START,
+	OEN_TOS_END,
+	SMC_TYPE_FAST,
+	pncd_setup,
+	pncd_smc_handler
+);
+
+/* Define a SPD runtime service descriptor for standard SMC calls */
+DECLARE_RT_SVC(
+	pncd_std,
+	OEN_TOS_START,
+	OEN_TOS_END,
+	SMC_TYPE_YIELD,
+	NULL,
+	pncd_smc_handler
+);
diff --git a/services/spd/pncd/pncd_private.h b/services/spd/pncd/pncd_private.h
new file mode 100644
index 000000000..8c9b634d5
--- /dev/null
+++ b/services/spd/pncd/pncd_private.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2021-2022, ARM Limited and Contributors. All rights reserved.
+ * Portions copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __PNCD_PRIVATE_H__
+#define __PNCD_PRIVATE_H__
+
+#ifndef __ASSEMBLER__
+#include <stdint.h>
+#endif /* __ASSEMBLER __ */
+
+#include <context.h>
+#ifndef __ASSEMBLER__
+#include <lib/cassert.h>
+#endif /* __ASSEMBLER __ */
+
+#include <platform_def.h>
+
+/*******************************************************************************
+ * Constants that allow assembler code to preserve callee-saved registers of the
+ * C runtime context while performing a security state switch.
+ ******************************************************************************/
+#define PNCD_C_RT_CTX_X19		U(0x0)
+#define PNCD_C_RT_CTX_X20		U(0x8)
+#define PNCD_C_RT_CTX_X21		U(0x10)
+#define PNCD_C_RT_CTX_X22		U(0x18)
+#define PNCD_C_RT_CTX_X23		U(0x20)
+#define PNCD_C_RT_CTX_X24		U(0x28)
+#define PNCD_C_RT_CTX_X25		U(0x30)
+#define PNCD_C_RT_CTX_X26		U(0x38)
+#define PNCD_C_RT_CTX_X27		U(0x40)
+#define PNCD_C_RT_CTX_X28		U(0x48)
+#define PNCD_C_RT_CTX_X29		U(0x50)
+#define PNCD_C_RT_CTX_X30		U(0x58)
+#define PNCD_C_RT_CTX_SIZE		U(0x60)
+#define PNCD_C_RT_CTX_ENTRIES		(PNCD_C_RT_CTX_SIZE >> DWORD_SHIFT)
+
+#ifndef __ASSEMBLER__
+
+/* AArch64 callee saved general purpose register context structure. */
+DEFINE_REG_STRUCT(c_rt_regs, PNCD_C_RT_CTX_ENTRIES);
+
+/*
+ * Compile time assertion to ensure that both the compiler and linker
+ * have the same double word aligned view of the size of the C runtime
+ * register context.
+ */
+CASSERT(sizeof(c_rt_regs_t) == PNCD_C_RT_CTX_SIZE,
+		assert_spd_c_rt_regs_size_mismatch);
+
+/*******************************************************************************
+ * Structure which helps the SPD to maintain the per-cpu state of the SP.
+ * 'mpidr'          - mpidr of the CPU running PNC
+ * 'c_rt_ctx'       - stack address to restore C runtime context from after
+ *                    returning from a synchronous entry into the SP.
+ * 'cpu_ctx'        - space to maintain SP architectural state
+ ******************************************************************************/
+typedef struct pnc_context {
+	uint64_t mpidr;
+	uint64_t c_rt_ctx;
+	cpu_context_t cpu_ctx;
+} pnc_context_t;
+
+/*******************************************************************************
+ * Function & Data prototypes
+ ******************************************************************************/
+uint64_t pncd_enter_sp(uint64_t *c_rt_ctx);
+void __dead2 pncd_exit_sp(uint64_t c_rt_ctx, uint64_t ret);
+uint64_t pncd_synchronous_sp_entry(pnc_context_t *pnc_ctx);
+void __dead2 pncd_synchronous_sp_exit(pnc_context_t *pnc_ctx, uint64_t ret);
+void pncd_init_pnc_ep_state(struct entry_point_info *pnc_ep,
+				uint64_t pc,
+				pnc_context_t *pnc_ctx);
+#endif /* __ASSEMBLER__ */
+
+#endif /* __PNCD_PRIVATE_H__ */