1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | |
3 | #define pr_fmt(fmt) "efi: " fmt |
4 | |
5 | #include <linux/module.h> |
6 | #include <linux/init.h> |
7 | #include <linux/efi.h> |
8 | #include <linux/libfdt.h> |
9 | #include <linux/of_fdt.h> |
10 | |
11 | #include <asm/unaligned.h> |
12 | |
13 | enum { |
14 | SYSTAB, |
15 | MMBASE, |
16 | MMSIZE, |
17 | DCSIZE, |
18 | DCVERS, |
19 | |
20 | PARAMCOUNT |
21 | }; |
22 | |
23 | static __initconst const char name[][22] = { |
24 | [SYSTAB] = "System Table " , |
25 | [MMBASE] = "MemMap Address " , |
26 | [MMSIZE] = "MemMap Size " , |
27 | [DCSIZE] = "MemMap Desc. Size " , |
28 | [DCVERS] = "MemMap Desc. Version " , |
29 | }; |
30 | |
31 | static __initconst const struct { |
32 | const char path[17]; |
33 | u8 paravirt; |
34 | const char params[PARAMCOUNT][26]; |
35 | } dt_params[] = { |
36 | { |
37 | #ifdef CONFIG_XEN // <-------17------> |
38 | .path = "/hypervisor/uefi" , |
39 | .paravirt = 1, |
40 | .params = { |
41 | [SYSTAB] = "xen,uefi-system-table" , |
42 | [MMBASE] = "xen,uefi-mmap-start" , |
43 | [MMSIZE] = "xen,uefi-mmap-size" , |
44 | [DCSIZE] = "xen,uefi-mmap-desc-size" , |
45 | [DCVERS] = "xen,uefi-mmap-desc-ver" , |
46 | } |
47 | }, { |
48 | #endif |
49 | .path = "/chosen" , |
50 | .params = { // <-----------26-----------> |
51 | [SYSTAB] = "linux,uefi-system-table" , |
52 | [MMBASE] = "linux,uefi-mmap-start" , |
53 | [MMSIZE] = "linux,uefi-mmap-size" , |
54 | [DCSIZE] = "linux,uefi-mmap-desc-size" , |
55 | [DCVERS] = "linux,uefi-mmap-desc-ver" , |
56 | } |
57 | } |
58 | }; |
59 | |
60 | static int __init efi_get_fdt_prop(const void *fdt, int node, const char *pname, |
61 | const char *rname, void *var, int size) |
62 | { |
63 | const void *prop; |
64 | int len; |
65 | u64 val; |
66 | |
67 | prop = fdt_getprop(fdt, nodeoffset: node, name: pname, lenp: &len); |
68 | if (!prop) |
69 | return 1; |
70 | |
71 | val = (len == 4) ? (u64)be32_to_cpup(p: prop) : get_unaligned_be64(p: prop); |
72 | |
73 | if (size == 8) |
74 | *(u64 *)var = val; |
75 | else |
76 | *(u32 *)var = (val < U32_MAX) ? val : U32_MAX; // saturate |
77 | |
78 | if (efi_enabled(EFI_DBG)) |
79 | pr_info(" %s: 0x%0*llx\n" , rname, size * 2, val); |
80 | |
81 | return 0; |
82 | } |
83 | |
84 | u64 __init efi_get_fdt_params(struct efi_memory_map_data *mm) |
85 | { |
86 | const void *fdt = initial_boot_params; |
87 | unsigned long systab; |
88 | int i, j, node; |
89 | struct { |
90 | void *var; |
91 | int size; |
92 | } target[] = { |
93 | [SYSTAB] = { &systab, sizeof(systab) }, |
94 | [MMBASE] = { .var: &mm->phys_map, .size: sizeof(mm->phys_map) }, |
95 | [MMSIZE] = { .var: &mm->size, .size: sizeof(mm->size) }, |
96 | [DCSIZE] = { .var: &mm->desc_size, .size: sizeof(mm->desc_size) }, |
97 | [DCVERS] = { .var: &mm->desc_version, .size: sizeof(mm->desc_version) }, |
98 | }; |
99 | |
100 | BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(name)); |
101 | BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(dt_params[0].params)); |
102 | |
103 | if (!fdt) |
104 | return 0; |
105 | |
106 | for (i = 0; i < ARRAY_SIZE(dt_params); i++) { |
107 | node = fdt_path_offset(fdt, path: dt_params[i].path); |
108 | if (node < 0) |
109 | continue; |
110 | |
111 | if (efi_enabled(EFI_DBG)) |
112 | pr_info("Getting UEFI parameters from %s in DT:\n" , |
113 | dt_params[i].path); |
114 | |
115 | for (j = 0; j < ARRAY_SIZE(target); j++) { |
116 | const char *pname = dt_params[i].params[j]; |
117 | |
118 | if (!efi_get_fdt_prop(fdt, node, pname, rname: name[j], |
119 | var: target[j].var, size: target[j].size)) |
120 | continue; |
121 | if (!j) |
122 | goto notfound; |
123 | pr_err("Can't find property '%s' in DT!\n" , pname); |
124 | return 0; |
125 | } |
126 | if (dt_params[i].paravirt) |
127 | set_bit(EFI_PARAVIRT, addr: &efi.flags); |
128 | return systab; |
129 | } |
130 | notfound: |
131 | pr_info("UEFI not found.\n" ); |
132 | return 0; |
133 | } |
134 | |