1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/module.h>
5 #include <asm/text-patching.h>
6 #include <asm/alternative.h>
7 #include <asm/facility.h>
8 #include <asm/nospec-branch.h>
10 static int __initdata_or_module alt_instr_disabled;
12 static int __init disable_alternative_instructions(char *str)
14 alt_instr_disabled = 1;
18 early_param("noaltinstr", disable_alternative_instructions);
20 static void __init_or_module __apply_alternatives(struct alt_instr *start,
21 struct alt_instr *end)
24 u8 *instr, *replacement;
27 * The scan order should be from start to end. A later scanned
28 * alternative code can overwrite previously scanned alternative code.
30 for (a = start; a < end; a++) {
31 instr = (u8 *)&a->instr_offset + a->instr_offset;
32 replacement = (u8 *)&a->repl_offset + a->repl_offset;
34 if (!__test_facility(a->facility, alt_stfle_fac_list))
37 if (unlikely(a->instrlen % 2)) {
38 WARN_ONCE(1, "cpu alternatives instructions length is "
39 "odd, skipping patching\n");
43 s390_kernel_write(instr, replacement, a->instrlen);
47 void __init_or_module apply_alternatives(struct alt_instr *start,
48 struct alt_instr *end)
50 if (!alt_instr_disabled)
51 __apply_alternatives(start, end);
54 extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
55 void __init apply_alternative_instructions(void)
57 apply_alternatives(__alt_instructions, __alt_instructions_end);
60 static void do_sync_core(void *info)
65 void text_poke_sync(void)
67 on_each_cpu(do_sync_core, NULL, 1);
70 void text_poke_sync_lock(void)