1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Alternative live-patching for parisc.
4 * Copyright (C) 2018 Helge Deller <deller@gmx.de>
5 *
6 */
7
8 #include <asm/processor.h>
9 #include <asm/sections.h>
10 #include <asm/alternative.h>
11
12 #include <linux/module.h>
13
14 static int no_alternatives;
setup_no_alternatives(char * str)15 static int __init setup_no_alternatives(char *str)
16 {
17 no_alternatives = 1;
18 return 1;
19 }
20 __setup("no-alternatives", setup_no_alternatives);
21
apply_alternatives(struct alt_instr * start,struct alt_instr * end,const char * module_name)22 void __init_or_module apply_alternatives(struct alt_instr *start,
23 struct alt_instr *end, const char *module_name)
24 {
25 struct alt_instr *entry;
26 int index = 0, applied = 0;
27 int num_cpus = num_online_cpus();
28 u32 cond_check;
29
30 cond_check = ALT_COND_ALWAYS |
31 ((num_cpus == 1) ? ALT_COND_NO_SMP : 0) |
32 ((cache_info.dc_size == 0) ? ALT_COND_NO_DCACHE : 0) |
33 ((cache_info.ic_size == 0) ? ALT_COND_NO_ICACHE : 0) |
34 (running_on_qemu ? ALT_COND_RUN_ON_QEMU : 0) |
35 ((split_tlb == 0) ? ALT_COND_NO_SPLIT_TLB : 0) |
36 /*
37 * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
38 * set (bit #61, big endian), we have to flush and sync every
39 * time IO-PDIR is changed in Ike/Astro.
40 */
41 (((boot_cpu_data.cpu_type > pcxw_) &&
42 ((boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC) == 0))
43 ? ALT_COND_NO_IOC_FDC : 0);
44
45 for (entry = start; entry < end; entry++, index++) {
46
47 u32 *from, cond, replacement;
48 s32 len;
49
50 from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
51 len = entry->len;
52 cond = entry->cond;
53 replacement = entry->replacement;
54
55 WARN_ON(!cond);
56
57 if ((cond & ALT_COND_ALWAYS) == 0 && no_alternatives)
58 continue;
59
60 pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
61 index, cond, len, from, replacement);
62
63 /* Bounce out if none of the conditions are true. */
64 if ((cond & cond_check) == 0)
65 continue;
66
67 /* Want to replace pdtlb by a pdtlb,l instruction? */
68 if (replacement == INSN_PxTLB) {
69 replacement = *from;
70 if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */
71 replacement |= (1 << 10); /* set el bit */
72 }
73
74 /*
75 * Replace instruction with NOPs?
76 * For long distance insert a branch instruction instead.
77 */
78 if (replacement == INSN_NOP && len > 1)
79 replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */
80
81 pr_debug("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n",
82 index, cond, len, replacement, from, from);
83
84 if (len < 0) {
85 /* Replace multiple instruction by new code */
86 u32 *source;
87 len = -len;
88 source = (u32 *)((ulong)&entry->replacement + entry->replacement);
89 memcpy(from, source, 4 * len);
90 } else {
91 /* Replace by one instruction */
92 *from = replacement;
93 }
94 applied++;
95 }
96
97 pr_info("%s%salternatives: applied %d out of %d patches\n",
98 module_name ? : "", module_name ? " " : "",
99 applied, index);
100 }
101
102
apply_alternatives_all(void)103 void __init apply_alternatives_all(void)
104 {
105 set_kernel_text_rw(1);
106
107 apply_alternatives((struct alt_instr *) &__alt_instructions,
108 (struct alt_instr *) &__alt_instructions_end, NULL);
109
110 set_kernel_text_rw(0);
111 }
112