1// SPDX-License-Identifier: GPL-2.0
 2
 3#include <linux/uaccess.h>
 4#include <asm/nospec-branch.h>
 5#include <asm/abs_lowcore.h>
 6#include <asm/alternative.h>
 7#include <asm/facility.h>
 
 
 
 8
 9void __apply_alternatives(struct alt_instr *start, struct alt_instr *end, unsigned int ctx)
 
 
 
 
 
 
 
 
 
10{
11	u8 *instr, *replacement;
12	struct alt_instr *a;
13	bool replace;
14
15	/*
16	 * The scan order should be from start to end. A later scanned
17	 * alternative code can overwrite previously scanned alternative code.
18	 */
19	for (a = start; a < end; a++) {
20		if (!(a->ctx & ctx))
21			continue;
22		switch (a->type) {
23		case ALT_TYPE_FACILITY:
24			replace = test_facility(a->data);
25			break;
26		case ALT_TYPE_SPEC:
27			replace = nobp_enabled();
28			break;
29		case ALT_TYPE_LOWCORE:
30			replace = have_relocated_lowcore();
31			break;
32		default:
33			replace = false;
34		}
35		if (!replace)
36			continue;
37		instr = (u8 *)&a->instr_offset + a->instr_offset;
38		replacement = (u8 *)&a->repl_offset + a->repl_offset;
 
 
 
 
 
 
 
 
 
 
39		s390_kernel_write(instr, replacement, a->instrlen);
40	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
41}

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/module.h>
 3#include <linux/cpu.h>
 4#include <linux/smp.h>
 5#include <asm/text-patching.h>
 6#include <asm/alternative.h>
 7#include <asm/facility.h>
 8#include <asm/nospec-branch.h>
 9
10static int __initdata_or_module alt_instr_disabled;
11
12static int __init disable_alternative_instructions(char *str)
13{
14	alt_instr_disabled = 1;
15	return 0;
16}
17
18early_param("noaltinstr", disable_alternative_instructions);
19
20static void __init_or_module __apply_alternatives(struct alt_instr *start,
21						  struct alt_instr *end)
22{
 
23	struct alt_instr *a;
24	u8 *instr, *replacement;
25
26	/*
27	 * The scan order should be from start to end. A later scanned
28	 * alternative code can overwrite previously scanned alternative code.
29	 */
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;
33
34		if (!__test_facility(a->facility, alt_stfle_fac_list))
35			continue;
36
37		if (unlikely(a->instrlen % 2)) {
38			WARN_ONCE(1, "cpu alternatives instructions length is "
39				     "odd, skipping patching\n");
40			continue;
41		}
42
43		s390_kernel_write(instr, replacement, a->instrlen);
44	}
45}
46
47void __init_or_module apply_alternatives(struct alt_instr *start,
48					 struct alt_instr *end)
49{
50	if (!alt_instr_disabled)
51		__apply_alternatives(start, end);
52}
53
54extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
55void __init apply_alternative_instructions(void)
56{
57	apply_alternatives(__alt_instructions, __alt_instructions_end);
58}
59
60static void do_sync_core(void *info)
61{
62	sync_core();
63}
64
65void text_poke_sync(void)
66{
67	on_each_cpu(do_sync_core, NULL, 1);
68}
69
70void text_poke_sync_lock(void)
71{
72	cpus_read_lock();
73	text_poke_sync();
74	cpus_read_unlock();
75}