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 #include <asm/unaligned.h>
12
13 #include "efistub.h"
14
15 /*
16 * RISC-V requires the kernel image to placed 2 MB aligned base for 64 bit and
17 * 4MB for 32 bit.
18 */
19 #ifdef CONFIG_64BIT
20 #define MIN_KIMG_ALIGN SZ_2M
21 #else
22 #define MIN_KIMG_ALIGN SZ_4M
23 #endif
24
25 typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);
26
27 static unsigned long hartid;
28
get_boot_hartid_from_fdt(void)29 static int get_boot_hartid_from_fdt(void)
30 {
31 const void *fdt;
32 int chosen_node, len;
33 const void *prop;
34
35 fdt = get_efi_config_table(DEVICE_TREE_GUID);
36 if (!fdt)
37 return -EINVAL;
38
39 chosen_node = fdt_path_offset(fdt, "/chosen");
40 if (chosen_node < 0)
41 return -EINVAL;
42
43 prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
44 if (!prop)
45 return -EINVAL;
46
47 if (len == sizeof(u32))
48 hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop);
49 else if (len == sizeof(u64))
50 hartid = (unsigned long) fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop));
51 else
52 return -EINVAL;
53
54 return 0;
55 }
56
get_boot_hartid_from_efi(void)57 static efi_status_t get_boot_hartid_from_efi(void)
58 {
59 efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
60 struct riscv_efi_boot_protocol *boot_protocol;
61 efi_status_t status;
62
63 status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
64 (void **)&boot_protocol);
65 if (status != EFI_SUCCESS)
66 return status;
67 return efi_call_proto(boot_protocol, get_boot_hartid, &hartid);
68 }
69
check_platform_features(void)70 efi_status_t check_platform_features(void)
71 {
72 efi_status_t status;
73 int ret;
74
75 status = get_boot_hartid_from_efi();
76 if (status != EFI_SUCCESS) {
77 ret = get_boot_hartid_from_fdt();
78 if (ret) {
79 efi_err("Failed to get boot hartid!\n");
80 return EFI_UNSUPPORTED;
81 }
82 }
83 return EFI_SUCCESS;
84 }
85
efi_enter_kernel(unsigned long entrypoint,unsigned long fdt,unsigned long fdt_size)86 void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt,
87 unsigned long fdt_size)
88 {
89 unsigned long stext_offset = _start_kernel - _start;
90 unsigned long kernel_entry = entrypoint + stext_offset;
91 jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry;
92
93 /*
94 * Jump to real kernel here with following constraints.
95 * 1. MMU should be disabled.
96 * 2. a0 should contain hartid
97 * 3. a1 should DT address
98 */
99 csr_write(CSR_SATP, 0);
100 jump_kernel(hartid, fdt);
101 }
102
handle_kernel_image(unsigned long * image_addr,unsigned long * image_size,unsigned long * reserve_addr,unsigned long * reserve_size,efi_loaded_image_t * image,efi_handle_t image_handle)103 efi_status_t handle_kernel_image(unsigned long *image_addr,
104 unsigned long *image_size,
105 unsigned long *reserve_addr,
106 unsigned long *reserve_size,
107 efi_loaded_image_t *image,
108 efi_handle_t image_handle)
109 {
110 unsigned long kernel_size = 0;
111 unsigned long preferred_addr;
112 efi_status_t status;
113
114 kernel_size = _edata - _start;
115 *image_addr = (unsigned long)_start;
116 *image_size = kernel_size + (_end - _edata);
117
118 /*
119 * RISC-V kernel maps PAGE_OFFSET virtual address to the same physical
120 * address where kernel is booted. That's why kernel should boot from
121 * as low as possible to avoid wastage of memory. Currently, dram_base
122 * is occupied by the firmware. So the preferred address for kernel to
123 * boot is next aligned address. If preferred address is not available,
124 * relocate_kernel will fall back to efi_low_alloc_above to allocate
125 * lowest possible memory region as long as the address and size meets
126 * the alignment constraints.
127 */
128 preferred_addr = MIN_KIMG_ALIGN;
129 status = efi_relocate_kernel(image_addr, kernel_size, *image_size,
130 preferred_addr, MIN_KIMG_ALIGN, 0x0);
131
132 if (status != EFI_SUCCESS) {
133 efi_err("Failed to relocate kernel\n");
134 *image_size = 0;
135 }
136 return status;
137 }
138