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