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
|
// SPDX-License-Identifier: GPL-2.0+
/*
* MIPS Relocation
*
* Copyright (c) 2017 Imagination Technologies Ltd.
*
* Relocation data, found in the .rel section, is generated by the mips-relocs
* tool & contains a record of all locations in the U-Boot binary that need to
* be fixed up during relocation.
*
* The data is a sequence of unsigned integers, which are of somewhat arbitrary
* size. This is achieved by encoding integers as a sequence of bytes, each of
* which contains 7 bits of data with the most significant bit indicating
* whether any further bytes need to be read. The least significant bits of the
* integer are found in the first byte - ie. it somewhat resembles little
* endian.
*
* Each pair of two integers represents a relocation that must be applied. The
* first integer represents the type of relocation as a standard ELF relocation
* type (ie. R_MIPS_*). The second integer represents the offset at which to
* apply the relocation, relative to the previous relocation or for the first
* relocation the start of the relocated .text section.
*
* The end of the relocation data is indicated when type R_MIPS_NONE (0) is
* read, at which point no further integers should be read. That is, the
* terminating R_MIPS_NONE reloc includes no offset.
*/
#include <common.h>
#include <cpu_func.h>
#include <init.h>
#include <asm/relocs.h>
#include <asm/sections.h>
#include <linux/bitops.h>
/**
* read_uint() - Read an unsigned integer from the buffer
* @buf: pointer to a pointer to the reloc buffer
*
* Read one whole unsigned integer from the relocation data pointed to by @buf,
* advancing @buf past the bytes encoding the integer.
*
* Returns: the integer read from @buf
*/
static unsigned long read_uint(uint8_t **buf)
{
unsigned long val = 0;
unsigned int shift = 0;
uint8_t new;
do {
new = *(*buf)++;
val |= (new & 0x7f) << shift;
shift += 7;
} while (new & 0x80);
return val;
}
/**
* apply_reloc() - Apply a single relocation
* @type: the type of reloc (R_MIPS_*)
* @addr: the address that the reloc should be applied to
* @off: the relocation offset, ie. number of bytes we're moving U-Boot by
*
* Apply a single relocation of type @type at @addr. This function is
* intentionally simple, and does the bare minimum needed to fixup the
* relocated U-Boot - in particular, it does not check for overflows.
*/
static void apply_reloc(unsigned int type, void *addr, long off, uint8_t *buf)
{
uint32_t u32;
switch (type) {
case R_MIPS_26:
u32 = *(uint32_t *)addr;
u32 = (u32 & GENMASK(31, 26)) |
((u32 + (off >> 2)) & GENMASK(25, 0));
*(uint32_t *)addr = u32;
break;
case R_MIPS_32:
*(uint32_t *)addr += off;
break;
case R_MIPS_64:
*(uint64_t *)addr += off;
break;
case R_MIPS_HI16:
*(uint32_t *)addr += off >> 16;
break;
default:
panic("Unhandled reloc type %u (@ %p), bss used before relocation?\n",
type, buf);
}
}
/**
* relocate_code() - Relocate U-Boot, generally from flash to DDR
* @start_addr_sp: new stack pointer
* @new_gd: pointer to relocated global data
* @relocaddr: the address to relocate to
*
* Relocate U-Boot from its current location (generally in flash) to a new one
* (generally in DDR). This function will copy the U-Boot binary & apply
* relocations as necessary, then jump to board_init_r in the new build of
* U-Boot. As such, this function does not return.
*/
void relocate_code(ulong start_addr_sp, gd_t *new_gd, ulong relocaddr)
{
unsigned long addr, length, bss_len;
uint8_t *buf, *bss_start;
unsigned int type;
long off;
/*
* Ensure that we're relocating by an offset which is a multiple of
* 64KiB, ie. doesn't change the least significant 16 bits of any
* addresses. This allows us to discard R_MIPS_LO16 relocs, saving
* space in the U-Boot binary & complexity in handling them.
*/
off = relocaddr - (unsigned long)__text_start;
if (off & 0xffff)
panic("Mis-aligned relocation\n");
/* Copy U-Boot to RAM */
length = __image_copy_end - __text_start;
memcpy((void *)relocaddr, __text_start, length);
/* Now apply relocations to the copy in RAM */
buf = __rel_start;
addr = relocaddr;
while (true) {
type = read_uint(&buf);
if (type == R_MIPS_NONE)
break;
addr += read_uint(&buf) << 2;
apply_reloc(type, (void *)addr, off, buf);
}
/* Ensure the icache is coherent */
flush_cache(relocaddr, length);
/* Clear the .bss section */
bss_start = (uint8_t *)((unsigned long)__bss_start + off);
bss_len = (unsigned long)&__bss_end - (unsigned long)__bss_start;
memset(bss_start, 0, bss_len);
/* Jump to the relocated U-Boot */
asm volatile(
"move $29, %0\n"
" move $4, %1\n"
" move $5, %2\n"
" move $31, $0\n"
" jr %3"
: /* no outputs */
: "r"(start_addr_sp),
"r"(new_gd),
"r"(relocaddr),
"r"((unsigned long)board_init_r + off));
/* Since we jumped to the new U-Boot above, we won't get here */
unreachable();
}
|