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 long, unsigned long); 25 26 static unsigned long hartid; 27 28 static int 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 -EINVAL; 37 38 chosen_node = fdt_path_offset(fdt, "/chosen"); 39 if (chosen_node < 0) 40 return -EINVAL; 41 42 prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len); 43 if (!prop || len != sizeof(u32)) 44 return -EINVAL; 45 46 hartid = fdt32_to_cpu(*prop); 47 return 0; 48 } 49 50 static efi_status_t get_boot_hartid_from_efi(void) 51 { 52 efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID; 53 struct riscv_efi_boot_protocol *boot_protocol; 54 efi_status_t status; 55 56 status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL, 57 (void **)&boot_protocol); 58 if (status != EFI_SUCCESS) 59 return status; 60 return efi_call_proto(boot_protocol, get_boot_hartid, &hartid); 61 } 62 63 efi_status_t check_platform_features(void) 64 { 65 efi_status_t status; 66 int ret; 67 68 status = get_boot_hartid_from_efi(); 69 if (status != EFI_SUCCESS) { 70 ret = get_boot_hartid_from_fdt(); 71 if (ret) { 72 efi_err("Failed to get boot hartid!\n"); 73 return EFI_UNSUPPORTED; 74 } 75 } 76 return EFI_SUCCESS; 77 } 78 79 void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt, 80 unsigned long fdt_size) 81 { 82 unsigned long stext_offset = _start_kernel - _start; 83 unsigned long kernel_entry = entrypoint + stext_offset; 84 jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry; 85 86 /* 87 * Jump to real kernel here with following constraints. 88 * 1. MMU should be disabled. 89 * 2. a0 should contain hartid 90 * 3. a1 should DT address 91 */ 92 csr_write(CSR_SATP, 0); 93 jump_kernel(hartid, fdt); 94 } 95 96 efi_status_t handle_kernel_image(unsigned long *image_addr, 97 unsigned long *image_size, 98 unsigned long *reserve_addr, 99 unsigned long *reserve_size, 100 efi_loaded_image_t *image, 101 efi_handle_t image_handle) 102 { 103 unsigned long kernel_size = 0; 104 unsigned long preferred_addr; 105 efi_status_t status; 106 107 kernel_size = _edata - _start; 108 *image_addr = (unsigned long)_start; 109 *image_size = kernel_size + (_end - _edata); 110 111 /* 112 * RISC-V kernel maps PAGE_OFFSET virtual address to the same physical 113 * address where kernel is booted. That's why kernel should boot from 114 * as low as possible to avoid wastage of memory. Currently, dram_base 115 * is occupied by the firmware. So the preferred address for kernel to 116 * boot is next aligned address. If preferred address is not available, 117 * relocate_kernel will fall back to efi_low_alloc_above to allocate 118 * lowest possible memory region as long as the address and size meets 119 * the alignment constraints. 120 */ 121 preferred_addr = MIN_KIMG_ALIGN; 122 status = efi_relocate_kernel(image_addr, kernel_size, *image_size, 123 preferred_addr, MIN_KIMG_ALIGN, 0x0); 124 125 if (status != EFI_SUCCESS) { 126 efi_err("Failed to relocate kernel\n"); 127 *image_size = 0; 128 } 129 return status; 130 } 131