1 files changed, 85 insertions, 0 deletions

diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
new file mode 100644
index 000000000000..495ebd657e38
--- /dev/null
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
+                                 unsigned long *image_addr,
+                                 unsigned long *image_size,
+                                 unsigned long *reserve_addr,
+                                 unsigned long *reserve_size,
+                                 unsigned long dram_base,
+                                 efi_loaded_image_t *image)
+{
+        unsigned long nr_pages;
+        efi_status_t status;
+        /* Use alloc_addr to tranlsate between types */
+        efi_physical_addr_t alloc_addr;
+
+        /*
+         * Verify that the DRAM base address is compatible with the ARM
+         * boot protocol, which determines the base of DRAM by masking
+         * off the low 27 bits of the address at which the zImage is
+         * loaded. These assumptions are made by the decompressor,
+         * before any memory map is available.
+         */
+        dram_base = round_up(dram_base, SZ_128M);
+
+        /*
+         * Reserve memory for the uncompressed kernel image. This is
+         * all that prevents any future allocations from conflicting
+         * with the kernel. Since we can't tell from the compressed
+         * image how much DRAM the kernel actually uses (due to BSS
+         * size uncertainty) we allocate the maximum possible size.
+         * Do this very early, as prints can cause memory allocations
+         * that may conflict with this.
+         */
+        alloc_addr = dram_base;
+        *reserve_size = MAX_UNCOMP_KERNEL_SIZE;
+        nr_pages = round_up(*reserve_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
+        status = sys_table->boottime->allocate_pages(EFI_ALLOCATE_ADDRESS,
+                                                     EFI_LOADER_DATA,
+                                                     nr_pages, &alloc_addr);
+        if (status != EFI_SUCCESS) {
+                *reserve_size = 0;
+                pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
+                return status;
+        }
+        *reserve_addr = alloc_addr;
+
+        /*
+         * Relocate the zImage, so that it appears in the lowest 128 MB
+         * memory window.
+         */
+        *image_size = image->image_size;
+        status = efi_relocate_kernel(sys_table, image_addr, *image_size,
+                                     *image_size,
+                                     dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
+        if (status != EFI_SUCCESS) {
+                pr_efi_err(sys_table, "Failed to relocate kernel.\n");
+                efi_free(sys_table, *reserve_size, *reserve_addr);
+                *reserve_size = 0;
+                return status;
+        }
+
+        /*
+         * Check to see if we were able to allocate memory low enough
+         * in memory. The kernel determines the base of DRAM from the
+         * address at which the zImage is loaded.
+         */
+        if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
+                pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
+                efi_free(sys_table, *reserve_size, *reserve_addr);
+                *reserve_size = 0;
+                efi_free(sys_table, *image_size, *image_addr);
+                *image_size = 0;
+                return EFI_LOAD_ERROR;
+        }
+        return EFI_SUCCESS;
+}