* the GD ('global data') structure, both located in some readily
* available RAM (SRAM, locked cache...). In this context, VARIABLE
* global data, initialized or not (BSS), are UNAVAILABLE; only
- * CONSTANT initialized data are available.
+ * CONSTANT initialized data are available. GD should be zeroed
+ * before board_init_f() is called.
*
* 2. Call board_init_f(). This function prepares the hardware for
* execution from system RAM (DRAM, DDR...) As system RAM may not
* data include the relocation destination, the future stack, and
* the future GD location.
*
- * (the following applies only to non-SPL builds)
- *
* 3. Set up intermediate environment where the stack and GD are the
* ones allocated by board_init_f() in system RAM, but BSS and
* initialized non-const data are still not available.
*
- * 4. Call relocate_code(). This function relocates U-Boot from its
- * current location into the relocation destination computed by
- * board_init_f().
+ * 4a.For U-Boot proper (not SPL), call relocate_code(). This function
+ * relocates U-Boot from its current location into the relocation
+ * destination computed by board_init_f().
+ *
+ * 4b.For SPL, board_init_f() just returns (to crt0). There is no
+ * code relocation in SPL.
*
* 5. Set up final environment for calling board_init_r(). This
* environment has BSS (initialized to 0), initialized non-const
* data (initialized to their intended value), and stack in system
- * RAM. GD has retained values set by board_init_f(). Some CPUs
- * have some work left to do at this point regarding memory, so
- * call c_runtime_cpu_setup.
+ * RAM (for SPL moving the stack and GD into RAM is optional - see
+ * CONFIG_SPL_STACK_R). GD has retained values set by board_init_f().
+ *
+ * TODO: For SPL, implement stack relocation on AArch64.
*
- * 6. Branch to board_init_r().
+ * 6. For U-Boot proper (not SPL), some CPUs have some work left to do
+ * at this point regarding memory, so call c_runtime_cpu_setup.
+ *
+ * 7. Branch to board_init_r().
+ *
+ * For more information see 'Board Initialisation Flow in README.
*/
ENTRY(_main)
/*
* Set up initial C runtime environment and call board_init_f(0).
*/
-#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
+#if defined(CONFIG_TPL_BUILD) && defined(CONFIG_TPL_NEEDS_SEPARATE_STACK)
+ ldr x0, =(CONFIG_TPL_STACK)
+#elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
ldr x0, =(CONFIG_SPL_STACK)
+#elif defined(CONFIG_SYS_INIT_SP_BSS_OFFSET)
+ adr x0, __bss_start
+ add x0, x0, #CONFIG_SYS_INIT_SP_BSS_OFFSET
#else
ldr x0, =(CONFIG_SYS_INIT_SP_ADDR)
-#endif
- sub x18, x0, #GD_SIZE /* allocate one GD above SP */
- bic x18, x18, #0x7 /* 8-byte alignment for GD */
-zero_gd:
- sub x0, x0, #0x8
- str xzr, [x0]
- cmp x0, x18
- b.gt zero_gd
-#if defined(CONFIG_SYS_MALLOC_F_LEN)
- sub x0, x18, #CONFIG_SYS_MALLOC_F_LEN
- str x0, [x18, #GD_MALLOC_BASE]
#endif
bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */
+ mov x0, sp
+ bl board_init_f_alloc_reserve
+ mov sp, x0
+ /* set up gd here, outside any C code */
+ mov x18, x0
+ bl board_init_f_init_reserve
+
mov x0, #0
bl board_init_f
*/
ldr x0, [x18, #GD_START_ADDR_SP] /* x0 <- gd->start_addr_sp */
bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */
- ldr x18, [x18, #GD_BD] /* x18 <- gd->bd */
- sub x18, x18, #GD_SIZE /* new GD is below bd */
+ ldr x18, [x18, #GD_NEW_GD] /* x18 <- gd->new_gd */
adr lr, relocation_return
+#if CONFIG_POSITION_INDEPENDENT
+ /* Add in link-vs-runtime offset */
+ adr x0, _start /* x0 <- Runtime value of _start */
+ ldr x9, _TEXT_BASE /* x9 <- Linked value of _start */
+ sub x9, x9, x0 /* x9 <- Run-vs-link offset */
+ add lr, lr, x9
+#endif
+ /* Add in link-vs-relocation offset */
ldr x9, [x18, #GD_RELOC_OFF] /* x9 <- gd->reloc_off */
add lr, lr, x9 /* new return address after relocation */
ldr x0, [x18, #GD_RELOCADDR] /* x0 <- gd->relocaddr */
* Set up final (full) environment
*/
bl c_runtime_cpu_setup /* still call old routine */
+#endif /* !CONFIG_SPL_BUILD */
+#if defined(CONFIG_SPL_BUILD)
+ bl spl_relocate_stack_gd /* may return NULL */
+ /* set up gd here, outside any C code, if new stack is returned */
+ cmp x0, #0
+ csel x18, x0, x18, ne
+ /*
+ * Perform 'sp = (x0 != NULL) ? x0 : sp' while working
+ * around the constraint that conditional moves can not
+ * have 'sp' as an operand
+ */
+ mov x1, sp
+ cmp x0, #0
+ csel x0, x0, x1, ne
+ mov sp, x0
+#endif
/*
* Clear BSS section
*/
ldr x0, =__bss_start /* this is auto-relocated! */
ldr x1, =__bss_end /* this is auto-relocated! */
- mov x2, #0
clear_loop:
- str x2, [x0]
- add x0, x0, #8
+ str xzr, [x0], #8
cmp x0, x1
b.lo clear_loop
/* NOTREACHED - board_init_r() does not return */
-#endif /* !CONFIG_SPL_BUILD */
-
ENDPROC(_main)