arm64/efi: efistub: don't abort if base of DRAM is occupied

If we cannot relocate the kernel Image to its preferred offset of base of DRAM
plus TEXT_OFFSET, instead relocate it to the lowest available 2 MB boundary plus
TEXT_OFFSET. We may lose a bit of memory at the low end, but we can still
proceed normally otherwise.

Acked-by: Mark Salter <msalter@redhat.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 6 insertions, 10 deletions

diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
index 1317fef8dde9..d27dd982ff26 100644
--- a/arch/arm64/kernel/efi-stub.c
+++ b/arch/arm64/kernel/efi-stub.c
@@ -28,20 +28,16 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
         kernel_size = _edata - _text;
         if (*image_addr != (dram_base + TEXT_OFFSET)) {
                 kernel_memsize = kernel_size + (_end - _edata);
-                status = efi_relocate_kernel(sys_table, image_addr,
-                                             kernel_size, kernel_memsize,
-                                             dram_base + TEXT_OFFSET,
-                                             PAGE_SIZE);
+                status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,
+                                       SZ_2M, reserve_addr);
                 if (status != EFI_SUCCESS) {
                         pr_efi_err(sys_table, "Failed to relocate kernel\n");
                         return status;
                 }
-                if (*image_addr != (dram_base + TEXT_OFFSET)) {
-                        pr_efi_err(sys_table, "Failed to alloc kernel memory\n");
-                        efi_free(sys_table, kernel_memsize, *image_addr);
-                        return EFI_LOAD_ERROR;
-                }
-                *image_size = kernel_memsize;
+                memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,
+                       kernel_size);
+                *image_addr = *reserve_addr + TEXT_OFFSET;
+                *reserve_size = kernel_memsize + TEXT_OFFSET;
         }