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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/*
* Copyright (c) 2015 Google, Inc
*
* SPDX-License-Identifier: GPL-2.0
*
* Taken from coreboot file of the same name
*/
/*
* The SIPI vector is responsible for initializing the APs in the sytem. It
* loads microcode, sets up MSRs, and enables caching before calling into
* C code
*/
#include <asm/global_data.h>
#include <asm/msr-index.h>
#include <asm/processor.h>
#include <asm/processor-flags.h>
#include <asm/sipi.h>
#define CODE_SEG (X86_GDT_ENTRY_32BIT_CS * X86_GDT_ENTRY_SIZE)
#define DATA_SEG (X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE)
/*
* First we have the 16-bit section. Every AP process starts here.
* The simple task is to load U-Boot's Global Descriptor Table (GDT) to allow
* U-Boot's 32-bit code to become visible, then jump to ap_start.
*
* Note that this code is copied to RAM below 1MB in mp_init.c, and runs from
* there, but the 32-bit code (ap_start and onwards) is part of U-Boot and
* is therefore relocated to the top of RAM with other U-Boot code. This
* means that for the 16-bit code we must write relocatable code, but for the
* rest, we can do what we like.
*/
.text
.code16
.globl ap_start16
ap_start16:
cli
xorl %eax, %eax
movl %eax, %cr3 /* Invalidate TLB */
/* setup the data segment */
movw %cs, %ax
movw %ax, %ds
/* Use an address relative to the data segment for the GDT */
movl $gdtaddr, %ebx
subl $ap_start16, %ebx
data32 lgdt (%ebx)
movl %cr0, %eax
andl $(~(X86_CR0_PG | X86_CR0_AM | X86_CR0_WP | X86_CR0_NE | \
X86_CR0_TS | X86_CR0_EM | X86_CR0_MP)), %eax
orl $(X86_CR0_NW | X86_CR0_CD | X86_CR0_PE), %eax
movl %eax, %cr0
movl $ap_start_jmp, %eax
subl $ap_start16, %eax
movw %ax, %bp
/* Jump to ap_start within U-Boot */
data32 cs ljmp *(%bp)
.align 4
.globl sipi_params_16bit
sipi_params_16bit:
/* 48-bit far pointer */
ap_start_jmp:
.long 0 /* offset set to ap_start by U-Boot */
.word CODE_SEG /* segment */
.word 0 /* padding */
gdtaddr:
.word 0 /* limit */
.long 0 /* table */
.word 0 /* unused */
.globl ap_start16_code_end
ap_start16_code_end:
/*
* Set up the special 'fs' segment for global_data. Then jump to ap_continue
* to set up the AP.
*/
.globl ap_start
ap_start:
.code32
movw $DATA_SEG, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %ss
movw %ax, %gs
movw $(X86_GDT_ENTRY_32BIT_FS * X86_GDT_ENTRY_SIZE), %ax
movw %ax, %fs
/* Load the Interrupt descriptor table */
mov idt_ptr, %ebx
lidt (%ebx)
/* Obtain cpu number */
movl ap_count, %eax
1:
movl %eax, %ecx
inc %ecx
lock cmpxchg %ecx, ap_count
jnz 1b
/* Setup stacks for each CPU */
movl stack_size, %eax
mul %ecx
movl stack_top, %edx
subl %eax, %edx
mov %edx, %esp
/* Save cpu number */
mov %ecx, %esi
/* Determine if one should check microcode versions */
mov microcode_ptr, %edi
test %edi, %edi
jz microcode_done /* Bypass if no microde exists */
/* Get the Microcode version */
mov $1, %eax
cpuid
mov $MSR_IA32_UCODE_REV, %ecx
rdmsr
/* If something already loaded skip loading again */
test %edx, %edx
jnz microcode_done
/* Determine if parallel microcode loading is allowed */
cmp $0xffffffff, microcode_lock
je load_microcode
/* Protect microcode loading */
lock_microcode:
lock bts $0, microcode_lock
jc lock_microcode
load_microcode:
/* Load new microcode */
mov $MSR_IA32_UCODE_WRITE, %ecx
xor %edx, %edx
mov %edi, %eax
/*
* The microcode pointer is passed in pointing to the header. Adjust
* pointer to reflect the payload (header size is 48 bytes)
*/
add $UCODE_HEADER_LEN, %eax
pusha
wrmsr
popa
/* Unconditionally unlock microcode loading */
cmp $0xffffffff, microcode_lock
je microcode_done
xor %eax, %eax
mov %eax, microcode_lock
microcode_done:
/*
* Load MSRs. Each entry in the table consists of:
* 0: index,
* 4: value[31:0]
* 8: value[63:32]
* See struct saved_msr in mp_init.c.
*/
mov msr_table_ptr, %edi
mov msr_count, %ebx
test %ebx, %ebx
jz 1f
load_msr:
mov (%edi), %ecx
mov 4(%edi), %eax
mov 8(%edi), %edx
wrmsr
add $12, %edi
dec %ebx
jnz load_msr
1:
/* Enable caching */
mov %cr0, %eax
andl $(~(X86_CR0_CD | X86_CR0_NW)), %eax
mov %eax, %cr0
/* c_handler(cpu_num) */
movl %esi, %eax /* cpu_num */
mov c_handler, %eax
call *%eax
.align 4
.globl sipi_params
sipi_params:
idt_ptr:
.long 0
stack_top:
.long 0
stack_size:
.long 0
microcode_lock:
.long 0
microcode_ptr:
.long 0
msr_table_ptr:
.long 0
msr_count:
.long 0
c_handler:
.long 0
ap_count:
.long 0
|
