arm: arm64 32bit address relocation

Current relocation code is limited to 21bit PC-relative addressing
which might not be enough for bigger code sizes. The following patch
increases the addressing to 32bit PC-relative. This feature is
specially interesting if U-Boot is build without optimiation (-O0) as
the text section is increased significativelly.

Signed-off-by: Ibai Erkiaga <ibai.erkiaga-elorza@xilinx.com>

diff --git a/arch/arm/lib/relocate_64.S b/arch/arm/lib/relocate_64.S
index 7603f52..26d29c5 100644 (file)
--- a/arch/arm/lib/relocate_64.S
+++ b/arch/arm/lib/relocate_64.S
@@ -26,9 +26,10 @@ ENTRY(relocate_code)
        /*
         * Copy u-boot from flash to RAM
         */
-       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 */
+       adrp    x1, __image_copy_start          /* x1 <- address bits [31:12] */
+       add     x1, x1, :lo12:__image_copy_start/* x1 <- address bits [11:00] */
+       subs    x9, x0, x1                      /* x9 <- Run to copy offset */
+       b.eq    relocate_done                   /* skip relocation */
        /*
         * 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
@@ -42,8 +43,10 @@ ENTRY(relocate_code)
        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 */
+       adrp    x1, __image_copy_start          /* x1 <- address bits [31:12] */
+       add     x1, x1, :lo12:__image_copy_start/* x1 <- address bits [11:00] */
+       adrp    x2, __image_copy_end            /* x2 <- address bits [31:12] */
+       add     x2, x2, :lo12:__image_copy_end  /* x2 <- address bits [11:00] */
 copy_loop:
        ldp     x10, x11, [x1], #16     /* copy from source address [x1] */
        stp     x10, x11, [x0], #16     /* copy to   target address [x0] */
@@ -54,8 +57,10 @@ copy_loop:
        /*
         * Fix .rela.dyn relocations
         */
-       adr     x2, __rel_dyn_start     /* x2 <- Run &__rel_dyn_start */
-       adr     x3, __rel_dyn_end       /* x3 <- Run &__rel_dyn_end */
+       adrp    x2, __rel_dyn_start             /* x2 <- address bits [31:12] */
+       add     x2, x2, :lo12:__rel_dyn_start   /* x2 <- address bits [11:00] */
+       adrp    x3, __rel_dyn_end               /* x3 <- address bits [31:12] */
+       add     x3, x3, :lo12:__rel_dyn_end     /* x3 <- address bits [11:00] */
 fixloop:
        ldp     x0, x1, [x2], #16       /* (x0,x1) <- (SRC location, fixup) */
        ldr     x4, [x2], #8            /* x4 <- addend */