1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2020 Western Digital Corporation or its affiliates. 4 */ 5 6 #include <linux/efi.h> 7 8 #include <asm/efi.h> 9 #include <asm/sections.h> 10 #include <asm/unaligned.h> 11 12 #include "efistub.h" 13 14 unsigned long stext_offset(void) 15 { 16 /* 17 * When built as part of the kernel, the EFI stub cannot branch to the 18 * kernel proper via the image header, as the PE/COFF header is 19 * strictly not part of the in-memory presentation of the image, only 20 * of the file representation. So instead, we need to jump to the 21 * actual entrypoint in the .text region of the image. 22 */ 23 return _start_kernel - _start; 24 } 25 26 efi_status_t handle_kernel_image(unsigned long *image_addr, 27 unsigned long *image_size, 28 unsigned long *reserve_addr, 29 unsigned long *reserve_size, 30 efi_loaded_image_t *image, 31 efi_handle_t image_handle) 32 { 33 unsigned long kernel_size = 0; 34 unsigned long preferred_addr; 35 efi_status_t status; 36 37 kernel_size = _edata - _start; 38 *image_addr = (unsigned long)_start; 39 *image_size = kernel_size + (_end - _edata); 40 41 /* 42 * RISC-V kernel maps PAGE_OFFSET virtual address to the same physical 43 * address where kernel is booted. That's why kernel should boot from 44 * as low as possible to avoid wastage of memory. Currently, dram_base 45 * is occupied by the firmware. So the preferred address for kernel to 46 * boot is next aligned address. If preferred address is not available, 47 * relocate_kernel will fall back to efi_low_alloc_above to allocate 48 * lowest possible memory region as long as the address and size meets 49 * the alignment constraints. 50 */ 51 preferred_addr = EFI_KIMG_PREFERRED_ADDRESS; 52 status = efi_relocate_kernel(image_addr, kernel_size, *image_size, 53 preferred_addr, efi_get_kimg_min_align(), 54 0x0); 55 56 if (status != EFI_SUCCESS) { 57 efi_err("Failed to relocate kernel\n"); 58 *image_size = 0; 59 } 60 return status; 61 } 62