arm64: kernel: replace early 64-bit literal loads with move-immediates

When building a relocatable kernel, we currently rely on the fact that
early 64-bit literal loads need to be deferred to after the relocation
has been performed only if they involve symbol references, and not if
they involve assemble time constants. While this is not an unreasonable
assumption to make, it is better to switch to movk/movz sequences, since
these are guaranteed to be resolved at link time, simply because there are
no dynamic relocation types to describe them.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 0d487d90d221588dc25edb3d3cb1f727c14ebd21..dae9cabaadf56ab4a8125ee23ecb78c31f434e8e 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -337,7 +337,7 @@ __create_page_tables:
        cmp     x0, x6
        b.lo    1b
 
-       ldr     x7, =SWAPPER_MM_MMUFLAGS
+       mov     x7, SWAPPER_MM_MMUFLAGS
 
        /*
         * Create the identity mapping.
@@ -393,7 +393,7 @@ __create_page_tables:
         * Map the kernel image (starting with PHYS_OFFSET).
         */
        mov     x0, x26                         // swapper_pg_dir
-       ldr     x5, =KIMAGE_VADDR
+       mov_q   x5, KIMAGE_VADDR
        add     x5, x5, x23                     // add KASLR displacement
        create_pgd_entry x0, x5, x3, x6
        ldr     w6, =kernel_img_size
@@ -631,7 +631,7 @@ ENTRY(secondary_holding_pen)
        bl      el2_setup                       // Drop to EL1, w20=cpu_boot_mode
        bl      set_cpu_boot_mode_flag
        mrs     x0, mpidr_el1
-       ldr     x1, =MPIDR_HWID_BITMASK
+       mov_q   x1, MPIDR_HWID_BITMASK
        and     x0, x0, x1
        adr_l   x3, secondary_holding_pen_release
 pen:   ldr     x4, [x3]
@@ -773,7 +773,7 @@ __primary_switch:
        ldr     w9, =__rela_offset              // offset to reloc table
        ldr     w10, =__rela_size               // size of reloc table
 
-       ldr     x11, =KIMAGE_VADDR              // default virtual offset
+       mov_q   x11, KIMAGE_VADDR               // default virtual offset
        add     x11, x11, x23                   // actual virtual offset
        add     x8, x8, x11                     // __va(.dynsym)
        add     x9, x9, x11                     // __va(.rela)