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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
084ee1c6 | 2 | #include <linux/io.h> |
5ff3e2c3 | 3 | #include <linux/slab.h> |
084ee1c6 | 4 | #include <linux/memblock.h> |
163ea3c8 | 5 | #include <linux/mem_encrypt.h> |
084ee1c6 | 6 | |
d1163651 | 7 | #include <asm/set_memory.h> |
084ee1c6 JS |
8 | #include <asm/pgtable.h> |
9 | #include <asm/realmode.h> | |
18bc7bd5 | 10 | #include <asm/tlbflush.h> |
084ee1c6 | 11 | |
b429dbf6 | 12 | struct real_mode_header *real_mode_header; |
cda846f1 | 13 | u32 *trampoline_cr4_features; |
084ee1c6 | 14 | |
b234e8a0 TG |
15 | /* Hold the pgd entry used on booting additional CPUs */ |
16 | pgd_t trampoline_pgd_entry; | |
17 | ||
4f7b9226 | 18 | void __init reserve_real_mode(void) |
084ee1c6 JS |
19 | { |
20 | phys_addr_t mem; | |
5ff3e2c3 AL |
21 | size_t size = real_mode_size_needed(); |
22 | ||
23 | if (!size) | |
24 | return; | |
25 | ||
26 | WARN_ON(slab_is_available()); | |
4f7b9226 YL |
27 | |
28 | /* Has to be under 1M so we can execute real-mode AP code. */ | |
29 | mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE); | |
5ff3e2c3 AL |
30 | if (!mem) { |
31 | pr_info("No sub-1M memory is available for the trampoline\n"); | |
32 | return; | |
33 | } | |
4f7b9226 | 34 | |
4f7b9226 | 35 | memblock_reserve(mem, size); |
f560bd19 | 36 | set_real_mode_mem(mem); |
4f7b9226 YL |
37 | } |
38 | ||
d0de0f68 | 39 | static void __init setup_real_mode(void) |
4f7b9226 | 40 | { |
084ee1c6 | 41 | u16 real_mode_seg; |
7306006f | 42 | const u32 *rel; |
084ee1c6 | 43 | u32 count; |
b429dbf6 | 44 | unsigned char *base; |
7306006f | 45 | unsigned long phys_base; |
f37240f1 | 46 | struct trampoline_header *trampoline_header; |
b429dbf6 | 47 | size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob); |
f37240f1 JS |
48 | #ifdef CONFIG_X86_64 |
49 | u64 *trampoline_pgd; | |
638d957b | 50 | u64 efer; |
f37240f1 | 51 | #endif |
084ee1c6 | 52 | |
4f7b9226 | 53 | base = (unsigned char *)real_mode_header; |
084ee1c6 | 54 | |
163ea3c8 TL |
55 | /* |
56 | * If SME is active, the trampoline area will need to be in | |
57 | * decrypted memory in order to bring up other processors | |
fcdcd6cd | 58 | * successfully. This is not needed for SEV. |
163ea3c8 | 59 | */ |
fcdcd6cd TL |
60 | if (sme_active()) |
61 | set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT); | |
163ea3c8 | 62 | |
b429dbf6 | 63 | memcpy(base, real_mode_blob, size); |
084ee1c6 | 64 | |
7306006f PA |
65 | phys_base = __pa(base); |
66 | real_mode_seg = phys_base >> 4; | |
67 | ||
084ee1c6 JS |
68 | rel = (u32 *) real_mode_relocs; |
69 | ||
70 | /* 16-bit segment relocations. */ | |
7306006f PA |
71 | count = *rel++; |
72 | while (count--) { | |
73 | u16 *seg = (u16 *) (base + *rel++); | |
084ee1c6 JS |
74 | *seg = real_mode_seg; |
75 | } | |
76 | ||
77 | /* 32-bit linear relocations. */ | |
7306006f PA |
78 | count = *rel++; |
79 | while (count--) { | |
80 | u32 *ptr = (u32 *) (base + *rel++); | |
81 | *ptr += phys_base; | |
084ee1c6 JS |
82 | } |
83 | ||
f37240f1 JS |
84 | /* Must be perfomed *after* relocation. */ |
85 | trampoline_header = (struct trampoline_header *) | |
86 | __va(real_mode_header->trampoline_header); | |
87 | ||
48927bbb | 88 | #ifdef CONFIG_X86_32 |
fc8d7826 | 89 | trampoline_header->start = __pa_symbol(startup_32_smp); |
f37240f1 | 90 | trampoline_header->gdt_limit = __BOOT_DS + 7; |
fc8d7826 | 91 | trampoline_header->gdt_base = __pa_symbol(boot_gdt); |
48927bbb | 92 | #else |
79603879 PA |
93 | /* |
94 | * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR | |
95 | * so we need to mask it out. | |
96 | */ | |
638d957b PA |
97 | rdmsrl(MSR_EFER, efer); |
98 | trampoline_header->efer = efer & ~EFER_LMA; | |
cda846f1 | 99 | |
f37240f1 | 100 | trampoline_header->start = (u64) secondary_startup_64; |
cda846f1 | 101 | trampoline_cr4_features = &trampoline_header->cr4; |
18bc7bd5 | 102 | *trampoline_cr4_features = mmu_cr4_features; |
cda846f1 | 103 | |
46d010e0 TL |
104 | trampoline_header->flags = 0; |
105 | if (sme_active()) | |
106 | trampoline_header->flags |= TH_FLAGS_SME_ACTIVE; | |
107 | ||
f37240f1 | 108 | trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd); |
b234e8a0 | 109 | trampoline_pgd[0] = trampoline_pgd_entry.pgd; |
65ade2f8 | 110 | trampoline_pgd[511] = init_top_pgt[511].pgd; |
48927bbb | 111 | #endif |
084ee1c6 JS |
112 | } |
113 | ||
114 | /* | |
4f7b9226 | 115 | * reserve_real_mode() gets called very early, to guarantee the |
231b3642 | 116 | * availability of low memory. This is before the proper kernel page |
084ee1c6 | 117 | * tables are set up, so we cannot set page permissions in that |
231b3642 YL |
118 | * function. Also trampoline code will be executed by APs so we |
119 | * need to mark it executable at do_pre_smp_initcalls() at least, | |
120 | * thus run it as a early_initcall(). | |
084ee1c6 | 121 | */ |
d0de0f68 | 122 | static void __init set_real_mode_permissions(void) |
084ee1c6 | 123 | { |
b429dbf6 JS |
124 | unsigned char *base = (unsigned char *) real_mode_header; |
125 | size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob); | |
084ee1c6 | 126 | |
f156ffc4 | 127 | size_t ro_size = |
b429dbf6 JS |
128 | PAGE_ALIGN(real_mode_header->ro_end) - |
129 | __pa(base); | |
f156ffc4 JS |
130 | |
131 | size_t text_size = | |
b429dbf6 JS |
132 | PAGE_ALIGN(real_mode_header->ro_end) - |
133 | real_mode_header->text_start; | |
f156ffc4 JS |
134 | |
135 | unsigned long text_start = | |
b429dbf6 | 136 | (unsigned long) __va(real_mode_header->text_start); |
f156ffc4 | 137 | |
b429dbf6 JS |
138 | set_memory_nx((unsigned long) base, size >> PAGE_SHIFT); |
139 | set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT); | |
f156ffc4 | 140 | set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT); |
d0de0f68 AL |
141 | } |
142 | ||
143 | static int __init init_real_mode(void) | |
144 | { | |
145 | if (!real_mode_header) | |
146 | panic("Real mode trampoline was not allocated"); | |
147 | ||
148 | setup_real_mode(); | |
149 | set_real_mode_permissions(); | |
f156ffc4 | 150 | |
084ee1c6 JS |
151 | return 0; |
152 | } | |
d0de0f68 | 153 | early_initcall(init_real_mode); |