Rework handover interface between BL stages
This patch reworks the handover interface from: BL1 to BL2 and
BL2 to BL3-1. It removes the raise_el(), change_el(), drop_el()
and run_image() functions as they catered for code paths that were
never exercised.
BL1 calls bl1_run_bl2() to jump into BL2 instead of doing the same
by calling run_image(). Similarly, BL2 issues the SMC to transfer
execution to BL3-1 through BL1 directly. Only x0 and x1 are used
to pass arguments to BL31. These arguments and parameters for
running BL3-1 are passed through a reference to a
'el_change_info_t' structure. They were being passed value in
general purpose registers earlier.
Change-Id: Id4fd019a19a9595de063766d4a66295a2c9307e1
diff --git a/include/common/bl_common.h b/include/common/bl_common.h
index 1569962..72e2f6f 100644
--- a/include/common/bl_common.h
+++ b/include/common/bl_common.h
@@ -56,10 +56,17 @@
*****************************************************************************/
#define RUN_IMAGE 0xC0000000
+/*******************************************************************************
+ * Constants that allow assembler code to access members of and the
+ * 'el_change_info' structure at their correct offsets.
+ ******************************************************************************/
+#define EL_CHANGE_INFO_PC_OFFSET 0x0
+#define EL_CHANGE_INFO_ARGS_OFFSET 0x18
#ifndef __ASSEMBLY__
#include <cdefs.h> /* For __dead2 */
+#include <cassert.h>
/*******************************************************************************
* Structure used for telling the next BL how much of a particular type of
@@ -89,6 +96,8 @@
* This structure represents the superset of information needed while switching
* exception levels. The only two mechanisms to do so are ERET & SMC. In case of
* SMC all members apart from 'aapcs64_params' will be ignored.
+ * NOTE: BL1 expects entrypoint followed by spsr while processing SMC to jump
+ * to BL31 from the start of el_change_info
******************************************************************************/
typedef struct el_change_info {
unsigned long entrypoint;
@@ -103,6 +112,7 @@
* populated only if BL2 detects its presence.
******************************************************************************/
typedef struct bl31_args {
+ el_change_info_t bl31_image_info;
meminfo_t bl31_meminfo;
el_change_info_t bl32_image_info;
meminfo_t bl32_meminfo;
@@ -110,14 +120,29 @@
meminfo_t bl33_meminfo;
} bl31_args_t;
+
+/*
+ * Compile time assertions related to the 'el_change_info' structure to
+ * ensure that the assembler and the compiler view of the offsets of
+ * the structure members is the same.
+ */
+CASSERT(EL_CHANGE_INFO_PC_OFFSET == \
+ __builtin_offsetof(el_change_info_t, entrypoint), \
+ assert_BL31_pc_offset_mismatch);
+
+CASSERT(EL_CHANGE_INFO_ARGS_OFFSET == \
+ __builtin_offsetof(el_change_info_t, args), \
+ assert_BL31_args_offset_mismatch);
+
+CASSERT(sizeof(unsigned long) == __builtin_offsetof(el_change_info_t, spsr) - \
+ __builtin_offsetof(el_change_info_t, entrypoint), \
+ assert_entrypoint_and_spsr_should_be_adjacent);
+
/*******************************************************************************
* Function & variable prototypes
******************************************************************************/
extern unsigned long page_align(unsigned long, unsigned);
extern void change_security_state(unsigned int);
-extern void __dead2 drop_el(aapcs64_params_t *, unsigned long, unsigned long);
-extern void __dead2 raise_el(aapcs64_params_t *);
-extern void __dead2 change_el(el_change_info_t *);
extern void init_bl2_mem_layout(meminfo_t *,
meminfo_t *,
unsigned int,
@@ -130,11 +155,6 @@
const char *,
unsigned int,
unsigned long);
-extern void __dead2 run_image(unsigned long entrypoint,
- unsigned long spsr,
- unsigned long security_state,
- void *first_arg,
- void *second_arg);
extern unsigned long *get_el_change_mem_ptr(void);
extern const char build_message[];