fix(rmmd): add missing padding to RMM Boot Manifest and initialize it

This patch also:
     * Enforces the check of RES0 fields on EL3-RMM boot interface
       and manifest
     * Fixes a couple of nits on the EL3-RMM Boot Interface
       documentation.

Signed-off-by: Javier Almansa Sobrino <javier.almansasobrino@arm.com>
Change-Id: Idb9e38f9fcda2ba0655646a1e2c4fdbabd5cdc40

docs/components/rmm-el3-comms-spec.rst

@@ -101,7 +101,7 @@ During cold boot RMM expects the following register values:
    x2,Maximum number of CPUs to be supported at runtime. RMM should ensure that it can support this maximum number.
    x3,Base address for the shared buffer used for communication between EL3 firmware and RMM. This buffer must be of 4KB size (1 page). The boot manifest must be present at the base of this shared buffer during cold boot.
 
-During cold boot, EL3 firmware needs to allocate a 4K page that will be
+During cold boot, EL3 firmware needs to allocate a 4KB page that will be
 passed to RMM in x3. This memory will be used as shared buffer for communication
 between EL3 and RMM. It must be assigned to Realm world and must be mapped with
 Normal memory attributes (IWB-OWB-ISH) at EL3. At boot, this memory will be
@@ -522,8 +522,8 @@ _____
 
 .. _rmm_el3_manifest_struct:
 
-RMM-EL3 Boot Manifest Version
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+RMM-EL3 Boot Manifest structure
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The RMM-EL3 Boot Manifest structure contains platform boot information passed
 from EL3 to RMM. The width of the Boot Manifest is 128 bits

include/services/rmm_core_manifest.h

@@ -38,6 +38,7 @@
 /* Boot manifest core structure as per v0.1 */
 typedef struct rmm_manifest {
 	uint32_t version;	/* Manifest version */
+	uint32_t padding;	/* RES0 */
 	uintptr_t plat_data;	/* Manifest platform data */
 } rmm_manifest_t;
 

plat/arm/board/fvp/fvp_common.c

@@ -536,6 +536,7 @@ int plat_rmmd_load_manifest(rmm_manifest_t *manifest)
 	assert(manifest != NULL);
 
 	manifest->version = RMMD_MANIFEST_VERSION;
+	manifest->padding = 0U; /* RES0 */
 	manifest->plat_data = (uintptr_t)NULL;
 
 	return 0;

plat/arm/common/trp/arm_trp_setup.c

@@ -28,6 +28,9 @@ static console_t arm_trp_runtime_console;
 
 static int arm_trp_process_manifest(rmm_manifest_t *manifest)
 {
+	/* padding field on the manifest must be RES0 */
+	assert(manifest->padding == 0U);
+
 	/* Verify the Boot Manifest Version. Only the Major is considered */
 	if (RMMD_MANIFEST_VERSION_MAJOR !=
 		RMMD_GET_MANIFEST_VERSION_MAJOR(manifest->version)) {

services/std_svc/rmmd/trp/trp_entry.S

@@ -83,7 +83,17 @@ trp_head:
 	mov	x3, x23
 	bl	trp_setup
 	bl	trp_main
+	b	1f
+
 warm_boot:
+	mov	x0, x20
+	mov	x1, x21
+	mov	x2, x22
+	mov	x3, x23
+	bl	trp_validate_warmboot_args
+	cbnz	x0, trp_panic /* Failed to validate warmboot args */
+
+1:
 	mov_imm	x0, RMM_BOOT_COMPLETE
 	mov	x1, xzr /* RMM_BOOT_SUCCESS */
 	smc	#0

services/std_svc/rmmd/trp/trp_main.c

@@ -66,6 +66,24 @@ void trp_setup(uint64_t x0,
 	trp_early_platform_setup((rmm_manifest_t *)trp_shared_region_start);
 }
 
+int trp_validate_warmboot_args(uint64_t x0, uint64_t x1,
+			       uint64_t x2, uint64_t x3)
+{
+	/*
+	 * Validate boot parameters for warm boot
+	 *
+	 * According to the Boot Interface ABI v.0.1, the parameters
+	 * received from EL3 during warm boot are:
+	 *
+	 * x0: CPUID (verified earlier so not used here)
+	 * [x1:x3]: RES0
+	 */
+
+	(void)x0;
+
+	return ((x1 | x2 | x3) == 0UL) ? 0 : E_RMM_BOOT_UNKNOWN;
+}
+
 /* Main function for TRP */
 void trp_main(void)
 {

services/std_svc/rmmd/trp/trp_private.h

@@ -53,5 +53,9 @@ void trp_setup(uint64_t x0,
 	       uint64_t x2,
 	       uint64_t x3);
 
+/* Validate arguments for warm boot only */
+int trp_validate_warmboot_args(uint64_t x0, uint64_t x1,
+			       uint64_t x2, uint64_t x3);
+
 #endif /* __ASSEMBLER__ */
 #endif /* TRP_PRIVATE_H */