1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Alternative live-patching for parisc.
4*4882a593Smuzhiyun * Copyright (C) 2018 Helge Deller <deller@gmx.de>
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <asm/processor.h>
9*4882a593Smuzhiyun #include <asm/sections.h>
10*4882a593Smuzhiyun #include <asm/alternative.h>
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/module.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun static int no_alternatives;
setup_no_alternatives(char * str)15*4882a593Smuzhiyun static int __init setup_no_alternatives(char *str)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun no_alternatives = 1;
18*4882a593Smuzhiyun return 1;
19*4882a593Smuzhiyun }
20*4882a593Smuzhiyun __setup("no-alternatives", setup_no_alternatives);
21*4882a593Smuzhiyun
apply_alternatives(struct alt_instr * start,struct alt_instr * end,const char * module_name)22*4882a593Smuzhiyun void __init_or_module apply_alternatives(struct alt_instr *start,
23*4882a593Smuzhiyun struct alt_instr *end, const char *module_name)
24*4882a593Smuzhiyun {
25*4882a593Smuzhiyun struct alt_instr *entry;
26*4882a593Smuzhiyun int index = 0, applied = 0;
27*4882a593Smuzhiyun int num_cpus = num_online_cpus();
28*4882a593Smuzhiyun u32 cond_check;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun cond_check = ALT_COND_ALWAYS |
31*4882a593Smuzhiyun ((num_cpus == 1) ? ALT_COND_NO_SMP : 0) |
32*4882a593Smuzhiyun ((cache_info.dc_size == 0) ? ALT_COND_NO_DCACHE : 0) |
33*4882a593Smuzhiyun ((cache_info.ic_size == 0) ? ALT_COND_NO_ICACHE : 0) |
34*4882a593Smuzhiyun (running_on_qemu ? ALT_COND_RUN_ON_QEMU : 0) |
35*4882a593Smuzhiyun ((split_tlb == 0) ? ALT_COND_NO_SPLIT_TLB : 0) |
36*4882a593Smuzhiyun /*
37*4882a593Smuzhiyun * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
38*4882a593Smuzhiyun * set (bit #61, big endian), we have to flush and sync every
39*4882a593Smuzhiyun * time IO-PDIR is changed in Ike/Astro.
40*4882a593Smuzhiyun */
41*4882a593Smuzhiyun (((boot_cpu_data.cpu_type > pcxw_) &&
42*4882a593Smuzhiyun ((boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC) == 0))
43*4882a593Smuzhiyun ? ALT_COND_NO_IOC_FDC : 0);
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun for (entry = start; entry < end; entry++, index++) {
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun u32 *from, cond, replacement;
48*4882a593Smuzhiyun s32 len;
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun from = (u32 *)((ulong)&entry->orig_offset + entry->orig_offset);
51*4882a593Smuzhiyun len = entry->len;
52*4882a593Smuzhiyun cond = entry->cond;
53*4882a593Smuzhiyun replacement = entry->replacement;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun WARN_ON(!cond);
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun if ((cond & ALT_COND_ALWAYS) == 0 && no_alternatives)
58*4882a593Smuzhiyun continue;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
61*4882a593Smuzhiyun index, cond, len, from, replacement);
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun /* Bounce out if none of the conditions are true. */
64*4882a593Smuzhiyun if ((cond & cond_check) == 0)
65*4882a593Smuzhiyun continue;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun /* Want to replace pdtlb by a pdtlb,l instruction? */
68*4882a593Smuzhiyun if (replacement == INSN_PxTLB) {
69*4882a593Smuzhiyun replacement = *from;
70*4882a593Smuzhiyun if (boot_cpu_data.cpu_type >= pcxu) /* >= pa2.0 ? */
71*4882a593Smuzhiyun replacement |= (1 << 10); /* set el bit */
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun /*
75*4882a593Smuzhiyun * Replace instruction with NOPs?
76*4882a593Smuzhiyun * For long distance insert a branch instruction instead.
77*4882a593Smuzhiyun */
78*4882a593Smuzhiyun if (replacement == INSN_NOP && len > 1)
79*4882a593Smuzhiyun replacement = 0xe8000002 + (len-2)*8; /* "b,n .+8" */
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun pr_debug("ALTERNATIVE %3d: Cond %2x, Replace %2d instructions to 0x%08x @ 0x%px (%pS)\n",
82*4882a593Smuzhiyun index, cond, len, replacement, from, from);
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun if (len < 0) {
85*4882a593Smuzhiyun /* Replace multiple instruction by new code */
86*4882a593Smuzhiyun u32 *source;
87*4882a593Smuzhiyun len = -len;
88*4882a593Smuzhiyun source = (u32 *)((ulong)&entry->replacement + entry->replacement);
89*4882a593Smuzhiyun memcpy(from, source, 4 * len);
90*4882a593Smuzhiyun } else {
91*4882a593Smuzhiyun /* Replace by one instruction */
92*4882a593Smuzhiyun *from = replacement;
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun applied++;
95*4882a593Smuzhiyun }
96*4882a593Smuzhiyun
97*4882a593Smuzhiyun pr_info("%s%salternatives: applied %d out of %d patches\n",
98*4882a593Smuzhiyun module_name ? : "", module_name ? " " : "",
99*4882a593Smuzhiyun applied, index);
100*4882a593Smuzhiyun }
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun
apply_alternatives_all(void)103*4882a593Smuzhiyun void __init apply_alternatives_all(void)
104*4882a593Smuzhiyun {
105*4882a593Smuzhiyun set_kernel_text_rw(1);
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun apply_alternatives((struct alt_instr *) &__alt_instructions,
108*4882a593Smuzhiyun (struct alt_instr *) &__alt_instructions_end, NULL);
109*4882a593Smuzhiyun
110*4882a593Smuzhiyun set_kernel_text_rw(0);
111*4882a593Smuzhiyun }
112