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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/io.h>
3#include <linux/slab.h>
4#include <linux/memblock.h>
5#include <linux/mem_encrypt.h>
6
7#include <asm/set_memory.h>
8#include <asm/pgtable.h>
9#include <asm/realmode.h>
10#include <asm/tlbflush.h>
11
12struct real_mode_header *real_mode_header;
13u32 *trampoline_cr4_features;
14
15/* Hold the pgd entry used on booting additional CPUs */
16pgd_t trampoline_pgd_entry;
17
18void __init reserve_real_mode(void)
19{
20 phys_addr_t mem;
21 size_t size = real_mode_size_needed();
22
23 if (!size)
24 return;
25
26 WARN_ON(slab_is_available());
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);
30 if (!mem) {
31 pr_info("No sub-1M memory is available for the trampoline\n");
32 return;
33 }
34
35 memblock_reserve(mem, size);
36 set_real_mode_mem(mem);
37}
38
39static void __init setup_real_mode(void)
40{
41 u16 real_mode_seg;
42 const u32 *rel;
43 u32 count;
44 unsigned char *base;
45 unsigned long phys_base;
46 struct trampoline_header *trampoline_header;
47 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
48#ifdef CONFIG_X86_64
49 u64 *trampoline_pgd;
50 u64 efer;
51#endif
52
53 base = (unsigned char *)real_mode_header;
54
55 /*
56 * If SME is active, the trampoline area will need to be in
57 * decrypted memory in order to bring up other processors
58 * successfully. This is not needed for SEV.
59 */
60 if (sme_active())
61 set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);
62
63 memcpy(base, real_mode_blob, size);
64
65 phys_base = __pa(base);
66 real_mode_seg = phys_base >> 4;
67
68 rel = (u32 *) real_mode_relocs;
69
70 /* 16-bit segment relocations. */
71 count = *rel++;
72 while (count--) {
73 u16 *seg = (u16 *) (base + *rel++);
74 *seg = real_mode_seg;
75 }
76
77 /* 32-bit linear relocations. */
78 count = *rel++;
79 while (count--) {
80 u32 *ptr = (u32 *) (base + *rel++);
81 *ptr += phys_base;
82 }
83
84 /* Must be perfomed *after* relocation. */
85 trampoline_header = (struct trampoline_header *)
86 __va(real_mode_header->trampoline_header);
87
88#ifdef CONFIG_X86_32
89 trampoline_header->start = __pa_symbol(startup_32_smp);
90 trampoline_header->gdt_limit = __BOOT_DS + 7;
91 trampoline_header->gdt_base = __pa_symbol(boot_gdt);
92#else
93 /*
94 * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
95 * so we need to mask it out.
96 */
97 rdmsrl(MSR_EFER, efer);
98 trampoline_header->efer = efer & ~EFER_LMA;
99
100 trampoline_header->start = (u64) secondary_startup_64;
101 trampoline_cr4_features = &trampoline_header->cr4;
102 *trampoline_cr4_features = mmu_cr4_features;
103
104 trampoline_header->flags = 0;
105 if (sme_active())
106 trampoline_header->flags |= TH_FLAGS_SME_ACTIVE;
107
108 trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
109 trampoline_pgd[0] = trampoline_pgd_entry.pgd;
110 trampoline_pgd[511] = init_top_pgt[511].pgd;
111#endif
112}
113
114/*
115 * reserve_real_mode() gets called very early, to guarantee the
116 * availability of low memory. This is before the proper kernel page
117 * tables are set up, so we cannot set page permissions in that
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().
121 */
122static void __init set_real_mode_permissions(void)
123{
124 unsigned char *base = (unsigned char *) real_mode_header;
125 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
126
127 size_t ro_size =
128 PAGE_ALIGN(real_mode_header->ro_end) -
129 __pa(base);
130
131 size_t text_size =
132 PAGE_ALIGN(real_mode_header->ro_end) -
133 real_mode_header->text_start;
134
135 unsigned long text_start =
136 (unsigned long) __va(real_mode_header->text_start);
137
138 set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
139 set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
140 set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
141}
142
143static 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();
150
151 return 0;
152}
153early_initcall(init_real_mode);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/io.h>
3#include <linux/slab.h>
4#include <linux/memblock.h>
5#include <linux/mem_encrypt.h>
6#include <linux/pgtable.h>
7
8#include <asm/set_memory.h>
9#include <asm/realmode.h>
10#include <asm/tlbflush.h>
11#include <asm/crash.h>
12#include <asm/sev.h>
13
14struct real_mode_header *real_mode_header;
15u32 *trampoline_cr4_features;
16
17/* Hold the pgd entry used on booting additional CPUs */
18pgd_t trampoline_pgd_entry;
19
20void __init reserve_real_mode(void)
21{
22 phys_addr_t mem;
23 size_t size = real_mode_size_needed();
24
25 if (!size)
26 return;
27
28 WARN_ON(slab_is_available());
29
30 /* Has to be under 1M so we can execute real-mode AP code. */
31 mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
32 if (!mem)
33 pr_info("No sub-1M memory is available for the trampoline\n");
34 else
35 set_real_mode_mem(mem);
36
37 /*
38 * Unconditionally reserve the entire fisrt 1M, see comment in
39 * setup_arch().
40 */
41 memblock_reserve(0, SZ_1M);
42}
43
44static void sme_sev_setup_real_mode(struct trampoline_header *th)
45{
46#ifdef CONFIG_AMD_MEM_ENCRYPT
47 if (sme_active())
48 th->flags |= TH_FLAGS_SME_ACTIVE;
49
50 if (sev_es_active()) {
51 /*
52 * Skip the call to verify_cpu() in secondary_startup_64 as it
53 * will cause #VC exceptions when the AP can't handle them yet.
54 */
55 th->start = (u64) secondary_startup_64_no_verify;
56
57 if (sev_es_setup_ap_jump_table(real_mode_header))
58 panic("Failed to get/update SEV-ES AP Jump Table");
59 }
60#endif
61}
62
63static void __init setup_real_mode(void)
64{
65 u16 real_mode_seg;
66 const u32 *rel;
67 u32 count;
68 unsigned char *base;
69 unsigned long phys_base;
70 struct trampoline_header *trampoline_header;
71 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
72#ifdef CONFIG_X86_64
73 u64 *trampoline_pgd;
74 u64 efer;
75#endif
76
77 base = (unsigned char *)real_mode_header;
78
79 /*
80 * If SME is active, the trampoline area will need to be in
81 * decrypted memory in order to bring up other processors
82 * successfully. This is not needed for SEV.
83 */
84 if (sme_active())
85 set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);
86
87 memcpy(base, real_mode_blob, size);
88
89 phys_base = __pa(base);
90 real_mode_seg = phys_base >> 4;
91
92 rel = (u32 *) real_mode_relocs;
93
94 /* 16-bit segment relocations. */
95 count = *rel++;
96 while (count--) {
97 u16 *seg = (u16 *) (base + *rel++);
98 *seg = real_mode_seg;
99 }
100
101 /* 32-bit linear relocations. */
102 count = *rel++;
103 while (count--) {
104 u32 *ptr = (u32 *) (base + *rel++);
105 *ptr += phys_base;
106 }
107
108 /* Must be performed *after* relocation. */
109 trampoline_header = (struct trampoline_header *)
110 __va(real_mode_header->trampoline_header);
111
112#ifdef CONFIG_X86_32
113 trampoline_header->start = __pa_symbol(startup_32_smp);
114 trampoline_header->gdt_limit = __BOOT_DS + 7;
115 trampoline_header->gdt_base = __pa_symbol(boot_gdt);
116#else
117 /*
118 * Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
119 * so we need to mask it out.
120 */
121 rdmsrl(MSR_EFER, efer);
122 trampoline_header->efer = efer & ~EFER_LMA;
123
124 trampoline_header->start = (u64) secondary_startup_64;
125 trampoline_cr4_features = &trampoline_header->cr4;
126 *trampoline_cr4_features = mmu_cr4_features;
127
128 trampoline_header->flags = 0;
129
130 trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
131 trampoline_pgd[0] = trampoline_pgd_entry.pgd;
132 trampoline_pgd[511] = init_top_pgt[511].pgd;
133#endif
134
135 sme_sev_setup_real_mode(trampoline_header);
136}
137
138/*
139 * reserve_real_mode() gets called very early, to guarantee the
140 * availability of low memory. This is before the proper kernel page
141 * tables are set up, so we cannot set page permissions in that
142 * function. Also trampoline code will be executed by APs so we
143 * need to mark it executable at do_pre_smp_initcalls() at least,
144 * thus run it as a early_initcall().
145 */
146static void __init set_real_mode_permissions(void)
147{
148 unsigned char *base = (unsigned char *) real_mode_header;
149 size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
150
151 size_t ro_size =
152 PAGE_ALIGN(real_mode_header->ro_end) -
153 __pa(base);
154
155 size_t text_size =
156 PAGE_ALIGN(real_mode_header->ro_end) -
157 real_mode_header->text_start;
158
159 unsigned long text_start =
160 (unsigned long) __va(real_mode_header->text_start);
161
162 set_memory_nx((unsigned long) base, size >> PAGE_SHIFT);
163 set_memory_ro((unsigned long) base, ro_size >> PAGE_SHIFT);
164 set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
165}
166
167static int __init init_real_mode(void)
168{
169 if (!real_mode_header)
170 panic("Real mode trampoline was not allocated");
171
172 setup_real_mode();
173 set_real_mode_permissions();
174
175 return 0;
176}
177early_initcall(init_real_mode);