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
|
// SPDX-License-Identifier: GPL-2.0
/*
* Alternative live-patching for parisc.
* Copyright (C) 2018 Helge Deller <deller@gmx.de>
*
*/
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/alternative.h>
#include <linux/module.h>
static int no_alternatives;
static int __init setup_no_alternatives(char *str)
{
no_alternatives = 1;
return 1;
}
__setup("no-alternatives", setup_no_alternatives);
void __init_or_module apply_alternatives(struct alt_instr *start,
struct alt_instr *end, const char *module_name)
{
struct alt_instr *entry;
int index = 0, applied = 0;
int num_cpus = num_online_cpus();
for (entry = start; entry < end; entry++, index++) {
u32 *from, len, cond, replacement;
from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
len = entry->len;
cond = entry->cond;
replacement = entry->replacement;
WARN_ON(!cond);
if (cond != ALT_COND_ALWAYS && no_alternatives)
continue;
pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
index, cond, len, from, replacement);
if ((cond & ALT_COND_NO_SMP) && (num_cpus != 1))
continue;
if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0))
continue;
if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0))
continue;
/*
* If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
* set (bit #61, big endian), we have to flush and sync every
* time IO-PDIR is changed in Ike/Astro.
*/
if ((cond & ALT_COND_NO_IOC_FDC) &&
((boot_cpu_data.cpu_type <= pcxw_) ||
(boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)))
continue;
/* Want to replace pdtlb by a pdtlb,l instruction? */
if (replacement == INSN_PxTLB) {
replacement = *from;
if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */
replacement |= (1 << 10); /* set el bit */
}
/*
* Replace instruction with NOPs?
* For long distance insert a branch instruction instead.
*/
if (replacement == INSN_NOP && len > 1)
replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */
pr_debug("Do %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
index, cond, len, from, replacement);
/* Replace instruction */
*from = replacement;
applied++;
}
pr_info("%s%salternatives: applied %d out of %d patches\n",
module_name ? : "", module_name ? " " : "",
applied, index);
}
void __init apply_alternatives_all(void)
{
set_kernel_text_rw(1);
apply_alternatives((struct alt_instr *) &__alt_instructions,
(struct alt_instr *) &__alt_instructions_end, NULL);
set_kernel_text_rw(0);
}
|
