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/unaligned.h>
11
12 #include "efistub.h"
13
14 typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);
15
16 static unsigned long hartid;
17
get_boot_hartid_from_fdt(void)18 static int get_boot_hartid_from_fdt(void)
19 {
20 const void *fdt;
21 int chosen_node, len;
22 const void *prop;
23
24 fdt = get_efi_config_table(DEVICE_TREE_GUID);
25 if (!fdt)
26 return -EINVAL;
27
28 chosen_node = fdt_path_offset(fdt, "/chosen");
29 if (chosen_node < 0)
30 return -EINVAL;
31
32 prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
33 if (!prop)
34 return -EINVAL;
35
36 if (len == sizeof(u32))
37 hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop);
38 else if (len == sizeof(u64))
39 hartid = (unsigned long) fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop));
40 else
41 return -EINVAL;
42
43 return 0;
44 }
45
get_boot_hartid_from_efi(void)46 static efi_status_t get_boot_hartid_from_efi(void)
47 {
48 efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
49 struct riscv_efi_boot_protocol *boot_protocol;
50 efi_status_t status;
51
52 status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
53 (void **)&boot_protocol);
54 if (status != EFI_SUCCESS)
55 return status;
56 return efi_call_proto(boot_protocol, get_boot_hartid, &hartid);
57 }
58
check_platform_features(void)59 efi_status_t check_platform_features(void)
60 {
61 efi_status_t status;
62 int ret;
63
64 status = get_boot_hartid_from_efi();
65 if (status != EFI_SUCCESS) {
66 ret = get_boot_hartid_from_fdt();
67 if (ret) {
68 efi_err("Failed to get boot hartid!\n");
69 return EFI_UNSUPPORTED;
70 }
71 }
72 return EFI_SUCCESS;
73 }
74
stext_offset(void)75 unsigned long __weak stext_offset(void)
76 {
77 /*
78 * This fallback definition is used by the EFI zboot stub, which loads
79 * the entire image so it can branch via the image header at offset #0.
80 */
81 return 0;
82 }
83
efi_enter_kernel(unsigned long entrypoint,unsigned long fdt,unsigned long fdt_size)84 void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt,
85 unsigned long fdt_size)
86 {
87 unsigned long kernel_entry = entrypoint + stext_offset();
88 jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry;
89
90 /*
91 * Jump to real kernel here with following constraints.
92 * 1. MMU should be disabled.
93 * 2. a0 should contain hartid
94 * 3. a1 should DT address
95 */
96 csr_write(CSR_SATP, 0);
97 jump_kernel(hartid, fdt);
98 }
99