ARMv8: Allow dynamic early stack pointer

[u-boot] / arch / arm / lib / crt0_64.S

diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
index f8e84b2fc8b56342b03c2d2c01f84791a76bbd7c..a181283e0fa9008162cfad63b5ddfd9adf98ed39 100644 (file)
--- a/arch/arm/lib/crt0_64.S
+++ b/arch/arm/lib/crt0_64.S
@@ -69,8 +69,13 @@ 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
@@ -93,10 +98,17 @@ ENTRY(_main)
  */
        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 */
@@ -109,8 +121,21 @@ relocation_return:
  */
        bl      c_runtime_cpu_setup             /* still call old routine */
 #endif /* !CONFIG_SPL_BUILD */
-
-/* TODO: For SPL, call spl_relocate_stack_gd() to alloc stack relocation */
+#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
@@ -118,8 +143,7 @@ relocation_return:
        ldr     x0, =__bss_start                /* this is auto-relocated! */
        ldr     x1, =__bss_end                  /* this is auto-relocated! */
 clear_loop:
-       str     xzr, [x0]
-       add     x0, x0, #8
+       str     xzr, [x0], #8
        cmp     x0, x1
        b.lo    clear_loop