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 #include <linux/libfdt.h> 8 9 #include <asm/efi.h> 10 #include <asm/sections.h> 11 12 #include "efistub.h" 13 14 /* 15 * RISC-V requires the kernel image to placed 2 MB aligned base for 64 bit and 16 * 4MB for 32 bit. 17 */ 18 #ifdef CONFIG_64BIT 19 #define MIN_KIMG_ALIGN SZ_2M 20 #else 21 #define MIN_KIMG_ALIGN SZ_4M 22 #endif 23 24 typedef void __noreturn (*jump_kernel_func)(unsigned int, unsigned long); 25 26 static u32 hartid; 27 28 static u32 get_boot_hartid_from_fdt(void) 29 { 30 const void *fdt; 31 int chosen_node, len; 32 const fdt32_t *prop; 33 34 fdt = get_efi_config_table(DEVICE_TREE_GUID); 35 if (!fdt) 36 return U32_MAX; 37 38 chosen_node = fdt_path_offset(fdt, "/chosen"); 39 if (chosen_node < 0) 40 return U32_MAX; 41 42 prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len); 43 if (!prop || len != sizeof(u32)) 44 return U32_MAX; 45 46 return fdt32_to_cpu(*prop); 47 } 48 49 efi_status_t check_platform_features(void) 50 { 51 hartid = get_boot_hartid_from_fdt(); 52 if (hartid == U32_MAX) { 53 efi_err("/chosen/boot-hartid missing or invalid!\n"); 54 return EFI_UNSUPPORTED; 55 } 56 return EFI_SUCCESS; 57 } 58 59 void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt, 60 unsigned long fdt_size) 61 { 62 unsigned long stext_offset = _start_kernel - _start; 63 unsigned long kernel_entry = entrypoint + stext_offset; 64 jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry; 65 66 /* 67 * Jump to real kernel here with following constraints. 68 * 1. MMU should be disabled. 69 * 2. a0 should contain hartid 70 * 3. a1 should DT address 71 */ 72 csr_write(CSR_SATP, 0); 73 jump_kernel(hartid, fdt); 74 } 75 76 efi_status_t handle_kernel_image(unsigned long *image_addr, 77 unsigned long *image_size, 78 unsigned long *reserve_addr, 79 unsigned long *reserve_size, 80 efi_loaded_image_t *image) 81 { 82 unsigned long kernel_size = 0; 83 unsigned long preferred_addr; 84 efi_status_t status; 85 86 kernel_size = _edata - _start; 87 *image_addr = (unsigned long)_start; 88 *image_size = kernel_size + (_end - _edata); 89 90 /* 91 * RISC-V kernel maps PAGE_OFFSET virtual address to the same physical 92 * address where kernel is booted. That's why kernel should boot from 93 * as low as possible to avoid wastage of memory. Currently, dram_base 94 * is occupied by the firmware. So the preferred address for kernel to 95 * boot is next aligned address. If preferred address is not available, 96 * relocate_kernel will fall back to efi_low_alloc_above to allocate 97 * lowest possible memory region as long as the address and size meets 98 * the alignment constraints. 99 */ 100 preferred_addr = MIN_KIMG_ALIGN; 101 status = efi_relocate_kernel(image_addr, kernel_size, *image_size, 102 preferred_addr, MIN_KIMG_ALIGN, 0x0); 103 104 if (status != EFI_SUCCESS) { 105 efi_err("Failed to relocate kernel\n"); 106 *image_size = 0; 107 } 108 return status; 109 } 110