Add runtime services framework

This patch introduces the framework to enable registration and
initialisation of runtime services. PSCI is registered and initialised
as a runtime service. Handling of runtime service requests will be
implemented in subsequent patches.

Change-Id: Id21e7ddc5a33d42b7d6e455b41155fc5441a9547

Makefile

@@ -36,8 +36,11 @@ else
   KBUILD_VERBOSE = 0
 endif
 
-CHECKPATCH_ARGS		=	--no-tree --no-signoff
-CHECKCODE_ARGS		=	--no-patch --no-tree --no-signoff
+# Checkpatch ignores
+CHECK_IGNORE		=	--ignore COMPLEX_MACRO
+
+CHECKPATCH_ARGS		=	--no-tree --no-signoff ${CHECK_IGNORE}
+CHECKCODE_ARGS		=	--no-patch --no-tree --no-signoff ${CHECK_IGNORE}
 
 ifeq "${KBUILD_VERBOSE}" "0"
 	Q=@

bl31/bl31.ld.S

@@ -50,6 +50,13 @@ SECTIONS
         *bl31_entrypoint.o(.text)
         *(.text)
         *(.rodata*)
+
+        /* Ensure 8-byte alignment for descriptors */
+        . = ALIGN(8);
+        __RT_SVC_DESCS_START__ = .;
+        *(rt_svc_descs)
+        __RT_SVC_DESCS_END__ = .;
+
         *(.vectors)
         __RO_END_UNALIGNED__ = .;
         /*

bl31/bl31_main.c

@@ -57,7 +57,6 @@ void bl31_arch_next_el_setup(void);
 void bl31_main(void)
 {
 	el_change_info *image_info;
-	unsigned long mpidr = read_mpidr();
 
 	/* Perform remaining generic architectural setup from EL3 */
 	bl31_arch_setup();
@@ -72,7 +71,7 @@ void bl31_main(void)
 	bl31_lib_init();
 
 	/* Initialize the runtime services e.g. psci */
-	runtime_svc_init(mpidr);
+	runtime_svc_init();
 
 	/* Clean caches before re-entering normal world */
 	dcsw_op_all(DCCSW);

common/psci/psci_setup.c

@@ -36,6 +36,7 @@
 #include <platform.h>
 #include <psci_private.h>
 #include <context_mgmt.h>
+#include <runtime_svc.h>
 
 /*******************************************************************************
  * Per cpu non-secure contexts used to program the architectural state prior
@@ -275,8 +276,9 @@ static unsigned int psci_init_aff_map(unsigned long mpidr,
  * level within the 'psci_aff_map' array. This allows restricting search of a
  * node at an affinity level between the indices in the limits array.
  ******************************************************************************/
-void psci_setup(unsigned long mpidr)
+int32_t psci_setup(void)
 {
+	unsigned long mpidr = read_mpidr();
 	int afflvl, affmap_idx, max_afflvl;
 	aff_map_node *node;
 
@@ -335,5 +337,16 @@ void psci_setup(unsigned long mpidr)
 	platform_setup_pm(&psci_plat_pm_ops);
 	assert(psci_plat_pm_ops);
 
-	return;
+	return 0;
 }
+
+/* Register PSCI as a run time service */
+DECLARE_RT_SVC(
+		psci,
+
+		OEN_STD_START,
+		OEN_STD_END,
+		SMC_TYPE_FAST,
+		psci_setup,
+		NULL
+);

common/runtime_svc.c

@@ -39,13 +39,106 @@
 #include <bl_common.h>
 #include <psci.h>
 #include <runtime_svc.h>
+#include <debug.h>
 
 /*******************************************************************************
- * Perform initialization of runtime services possibly across exception levels
- * in the secure address space e.g. psci & interrupt handling.
+ * The 'rt_svc_descs' array holds the runtime service descriptors exported by
+ * services by placing them in the 'rt_svc_descs' linker section.
+ * The 'rt_svc_descs_indices' array holds the index of a descriptor in the
+ * 'rt_svc_descs' array. When an SMC arrives, the OEN[29:24] bits and the call
+ * type[31] bit in the function id are combined to get an index into the
+ * 'rt_svc_descs_indices' array. This gives the index of the descriptor in the
+ * 'rt_svc_descs' array which contains the SMC handler.
  ******************************************************************************/
-void runtime_svc_init(unsigned long mpidr)
+#define RT_SVC_DESCS_START	((uint64_t) (&__RT_SVC_DESCS_START__))
+#define RT_SVC_DESCS_END	((uint64_t) (&__RT_SVC_DESCS_END__))
+uint8_t rt_svc_descs_indices[MAX_RT_SVCS];
+static rt_svc_desc *rt_svc_descs;
+
+/*******************************************************************************
+ * Simple routine to sanity check a runtime service descriptor before using it
+ ******************************************************************************/
+static int32_t validate_rt_svc_desc(rt_svc_desc *desc)
 {
-	psci_setup(mpidr);
+	if (desc == NULL)
+		return -EINVAL;
+
+	if (desc->start_oen > desc->end_oen)
+		return -EINVAL;
+
+	if (desc->end_oen >= OEN_LIMIT)
+		return -EINVAL;
+
+	if (desc->call_type != SMC_TYPE_FAST && desc->call_type != SMC_TYPE_STD)
+		return -EINVAL;
+
+	/* A runtime service having no init or handle function doesn't make sense */
+	if (desc->init == NULL && desc->handle == NULL)
+		return -EINVAL;
+
+	return 0;
+}
+
+/*******************************************************************************
+ * This function calls the initialisation routine in the descriptor exported by
+ * a runtime service. Once a descriptor has been validated, its start & end
+ * owning entity numbers and the call type are combined to form a unique oen.
+ * The unique oen is used as an index into the 'rt_svc_descs_indices' array.
+ * The index of the runtime service descriptor is stored at this index.
+ ******************************************************************************/
+void runtime_svc_init()
+{
+	int32_t rc = 0;
+	uint32_t index, start_idx, end_idx;
+	uint64_t rt_svc_descs_num;
+
+	/* If no runtime services are implemented then simply bail out */
+	rt_svc_descs_num = RT_SVC_DESCS_END - RT_SVC_DESCS_START;
+	rt_svc_descs_num /= sizeof(rt_svc_desc);
+	if (rt_svc_descs_num == 0)
+		return;
+
+	/* Initialise internal variables to invalid state */
+	memset(rt_svc_descs_indices, -1, sizeof(rt_svc_descs_indices));
+
+	rt_svc_descs = (rt_svc_desc *) RT_SVC_DESCS_START;
+	for (index = 0; index < rt_svc_descs_num; index++) {
+
+		/*
+		 * An invalid descriptor is an error condition since it is
+		 * difficult to predict the system behaviour in the absence
+		 * of this service.
+		 */
+		rc = validate_rt_svc_desc(&rt_svc_descs[index]);
+		if (rc) {
+			ERROR("Invalid runtime service descriptor 0x%x (%s)\n",
+					&rt_svc_descs[index],
+					rt_svc_descs[index].name);
+			goto error;
+		}
+
+		/*
+		 * Fill the indices corresponding to the start and end owning
+		 * entity numbers with the index of the descriptor which will
+		 * handle the SMCs for this owning entity range.
+		 */
+		start_idx = get_unique_oen(rt_svc_descs[index].start_oen,
+					   rt_svc_descs[index].call_type);
+		end_idx = get_unique_oen(rt_svc_descs[index].end_oen,
+					 rt_svc_descs[index].call_type);
+		for (; start_idx <= end_idx; start_idx++)
+			rt_svc_descs_indices[start_idx] = index;
+
+		/* Call the initialisation routine for this runtime service */
+		rc = rt_svc_descs[index].init();
+		if (rc) {
+			ERROR("Error initializing runtime service %s\n",
+					rt_svc_descs[index].name);
+			goto error;
+		}
+	}
+
 	return;
+error:
+	panic();
 }

include/psci.h

@@ -156,7 +156,6 @@ extern int psci_cpu_on(unsigned long,
 		       unsigned long);
 extern void psci_aff_on_finish_entry(void);
 extern void psci_aff_suspend_finish_entry(void);
-extern void psci_setup(unsigned long);
 #endif /*__ASSEMBLY__*/
 
 

include/runtime_svc.h

@@ -38,20 +38,47 @@
  ******************************************************************************/
 #define FUNCID_TYPE_SHIFT		31
 #define FUNCID_CC_SHIFT			30
-#define FUNCID_OWNER_SHIFT		24
+#define FUNCID_OEN_SHIFT		24
 #define FUNCID_NUM_SHIFT		0
 
 #define FUNCID_TYPE_MASK		0x1
 #define FUNCID_CC_MASK			0x1
-#define FUNCID_OWNER_MASK		0x3f
+#define FUNCID_OEN_MASK			0x3f
 #define FUNCID_NUM_MASK			0xffff
 
+#define FUNCID_TYPE_WIDTH		1
+#define FUNCID_CC_WIDTH			1
+#define FUNCID_OEN_WIDTH		6
+#define FUNCID_NUM_WIDTH		16
+
 #define GET_SMC_CC(id)			((id >> FUNCID_CC_SHIFT) & \
 					 FUNCID_CC_MASK)
 
 #define SMC_64				1
 #define SMC_32				0
 #define SMC_UNK				0xffffffff
+#define SMC_TYPE_FAST			1
+#define SMC_TYPE_STD			0
+
+/*******************************************************************************
+ * Owning entity number definitions inside the function id as per the SMC
+ * calling convention
+ ******************************************************************************/
+#define OEN_ARM_START			0
+#define OEN_ARM_END			0
+#define OEN_CPU_START			1
+#define OEN_CPU_END			1
+#define OEN_SIP_START			2
+#define OEN_SIP_END			2
+#define OEN_OEM_START			3
+#define OEN_OEM_END			3
+#define OEN_STD_START			4	/* Standard Calls */
+#define OEN_STD_END			4
+#define OEN_TAP_START			48	/* Trusted Applications */
+#define OEN_TAP_END			49
+#define OEN_TOS_START			50	/* Trusted OS */
+#define OEN_TOS_END			63
+#define OEN_LIMIT			64
 
 /*******************************************************************************
  * Constants to indicate type of exception to the common exception handler.
@@ -112,8 +139,77 @@
 #define GPREGS_FP_OFF		0x100
 #define GPREGS_LR_OFF		0x108
 
+/*
+ * Constants to allow the assembler access a runtime service
+ * descriptor
+ */
+#define SIZEOF_RT_SVC_DESC	32
+#define RT_SVC_DESC_INIT	16
+#define RT_SVC_DESC_HANDLE	24
+
+/*
+ * The function identifier has 6 bits for the owning entity number and
+ * single bit for the type of smc call. When taken together these
+ * values limit the maximum number of runtime services to 128.
+ */
+#define MAX_RT_SVCS		128
+
 #ifndef __ASSEMBLY__
 
+/* Prototype for runtime service initializing function */
+typedef int32_t (*rt_svc_init)(void);
+
+/* Convenience macros to return from SMC handler */
+#define SMC_RET1(_h, _x0)	{ \
+	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X0, (_x0)); \
+	return _x0; \
+}
+#define SMC_RET2(_h, _x0, _x1)	{ \
+	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X1, (_x1)); \
+	SMC_RET1(_h, (_x0)); \
+}
+#define SMC_RET3(_h, _x0, _x1, _x2)	{ \
+	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X2, (_x2)); \
+	SMC_RET2(_h, (_x0), (_x1)); \
+}
+#define SMC_RET4(_h, _x0, _x1, _x2, _x3)	{ \
+	write_ctx_reg(get_gpregs_ctx(_h), CTX_GPREG_X3, (_x3)); \
+	SMC_RET3(_h, (_x0), (_x1), (_x2)); \
+}
+
+
+/*
+ * Convenience macros to access general purpose registers using handle provided
+ * to SMC handler. These takes the offset values defined in context.h
+ */
+#define SMC_GET_GP(_h, _g) \
+	read_ctx_reg(get_gpregs_ctx(_h), (_g));
+#define SMC_SET_GP(_h, _g, _v) \
+	write_ctx_reg(get_gpregs_ctx(_h), (_g), (_v));
+
+/*
+ * Convenience macros to access EL3 context registers using handle provided to
+ * SMC handler. These takes the offset values defined in context.h
+ */
+#define SMC_GET_EL3(_h, _e) \
+	read_ctx_reg(get_el3state_ctx(_h), (_e));
+#define SMC_SET_EL3(_h, _e, _v) \
+	write_ctx_reg(get_el3state_ctx(_h), (_e), (_v));
+
+/*
+ * Prototype for runtime service SMC handler function. x0 (SMC Function ID) to
+ * x4 are as passed by the caller. Rest of the arguments to SMC and the context
+ * can be accessed using the handle pointer. The cookie parameter is reserved
+ * for future use
+ */
+typedef uint64_t (*rt_svc_handle)(uint32_t smc_fid,
+				  uint64_t x1,
+				  uint64_t x2,
+				  uint64_t x3,
+				  uint64_t x4,
+				  void *cookie,
+				  void *handle,
+				  uint64_t flags);
 typedef struct {
 	uint64_t x0;
 	uint64_t x1;
@@ -150,9 +246,31 @@ typedef struct {
 	 * Alignment constraint which allows save & restore of fp & lr on the
 	 * stack during exception handling
 	 */
-	uint64_t fp  __attribute__((__aligned__(16)));
+	uint64_t fp __aligned(16);
 	uint64_t lr;
-} __attribute__((__aligned__(16))) gp_regs;
+} __aligned(16) gp_regs;
+
+typedef struct {
+	uint8_t start_oen;
+	uint8_t end_oen;
+	uint8_t call_type;
+	const char *name;
+	rt_svc_init init;
+	rt_svc_handle handle;
+} rt_svc_desc;
+
+/*
+ * Convenience macro to declare a service descriptor
+ */
+#define DECLARE_RT_SVC(_name, _start, _end, _type, _setup, _smch) \
+	static const rt_svc_desc __svc_desc_ ## _name \
+		__attribute__ ((section("rt_svc_descs"), used)) = { \
+			_start, \
+			_end, \
+			_type, \
+			#_name, \
+			_setup, \
+			_smch }
 
 /*******************************************************************************
  * Compile time assertions to ensure that:
@@ -164,11 +282,39 @@ typedef struct {
 CASSERT((sizeof(gp_regs) == SIZEOF_GPREGS), assert_sizeof_gpregs_mismatch);
 CASSERT(GPREGS_FP_OFF == __builtin_offsetof(gp_regs, fp), \
 	assert_gpregs_fp_offset_mismatch);
+/*
+ * Compile time assertions related to the 'rt_svc_desc' structure to:
+ * 1. ensure that the assembler and the compiler view of the size
+ *    of the structure are the same.
+ * 2. ensure that the assembler and the compiler see the initialisation
+ *    routine at the same offset.
+ * 2. ensure that the assembler and the compiler see the handler
+ *    routine at the same offset.
+ */
+CASSERT((sizeof(rt_svc_desc) == SIZEOF_RT_SVC_DESC), \
+	assert_sizeof_rt_svc_desc_mismatch);
+CASSERT(RT_SVC_DESC_INIT == __builtin_offsetof(rt_svc_desc, init), \
+	assert_rt_svc_desc_init_offset_mismatch);
+CASSERT(RT_SVC_DESC_HANDLE == __builtin_offsetof(rt_svc_desc, handle), \
+	assert_rt_svc_desc_handle_offset_mismatch);
+
+
+/*
+ * This macro combines the call type and the owning entity number corresponding
+ * to a runtime service to generate a unique owning entity number. This unique
+ * oen is used to access an entry in the 'rt_svc_descs_indices' array. The entry
+ * contains the index of the service descriptor in the 'rt_svc_descs' array.
+ */
+#define get_unique_oen(oen, call_type)	((oen & FUNCID_OEN_MASK) |	\
+					((call_type & FUNCID_TYPE_MASK) \
+					 << FUNCID_OEN_WIDTH))
 
 /*******************************************************************************
  * Function & variable prototypes
  ******************************************************************************/
-extern void runtime_svc_init(unsigned long mpidr);
+extern void runtime_svc_init();
+extern uint64_t __RT_SVC_DESCS_START__;
+extern uint64_t __RT_SVC_DESCS_END__;
 
 #endif /*__ASSEMBLY__*/
 #endif /* __RUNTIME_SVC_H__ */