arm64: support running at addr other than linked to

[people/ms/u-boot.git] / arch / arm / lib / relocate_64.S

diff --git a/arch/arm/lib/relocate_64.S b/arch/arm/lib/relocate_64.S
index fdba004363af38de84ad7d8cd33db556aa6de4d7..04804524ed653dde1e7671d716dd7c99cdee81a3 100644 (file)
--- a/arch/arm/lib/relocate_64.S
+++ b/arch/arm/lib/relocate_64.S
@@ -27,11 +27,24 @@ ENTRY(relocate_code)
        /*
         * Copy u-boot from flash to RAM
         */
-       ldr     x1, =__image_copy_start /* x1 <- SRC &__image_copy_start */
-       subs    x9, x0, x1              /* x9 <- relocation offset */
+       adr     x1, __image_copy_start  /* x1 <- Run &__image_copy_start */
+       subs    x9, x0, x1              /* x8 <- Run to copy offset */
        b.eq    relocate_done           /* skip relocation */
-       ldr     x2, =__image_copy_end   /* x2 <- SRC &__image_copy_end */
+       /*
+        * Don't ldr x1, __image_copy_start here, since if the code is already
+        * running at an address other than it was linked to, that instruction
+        * will load the relocated value of __image_copy_start. To
+        * correctly apply relocations, we need to know the linked value.
+        *
+        * Linked &__image_copy_start, which we know was at
+        * CONFIG_SYS_TEXT_BASE, which is stored in _TEXT_BASE, as a non-
+        * relocated value, since it isn't a symbol reference.
+        */
+       ldr     x1, _TEXT_BASE          /* x1 <- Linked &__image_copy_start */
+       subs    x9, x0, x1              /* x9 <- Link to copy offset */
 
+       adr     x1, __image_copy_start  /* x1 <- Run &__image_copy_start */
+       adr     x2, __image_copy_end    /* x2 <- Run &__image_copy_end */
 copy_loop:
        ldp     x10, x11, [x1], #16     /* copy from source address [x1] */
        stp     x10, x11, [x0], #16     /* copy to   target address [x0] */
@@ -42,8 +55,8 @@ copy_loop:
        /*
         * Fix .rela.dyn relocations
         */
-       ldr     x2, =__rel_dyn_start    /* x2 <- SRC &__rel_dyn_start */
-       ldr     x3, =__rel_dyn_end      /* x3 <- SRC &__rel_dyn_end */
+       adr     x2, __rel_dyn_start     /* x2 <- Run &__rel_dyn_start */
+       adr     x3, __rel_dyn_end       /* x3 <- Run &__rel_dyn_end */
 fixloop:
        ldp     x0, x1, [x2], #16       /* (x0,x1) <- (SRC location, fixup) */
        ldr     x4, [x2], #8            /* x4 <- addend */