1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2025 Chen Miao
4 *
5 * Based on arch/arm/kernel/jump_label.c
6 */
7 #include <linux/jump_label.h>
8 #include <linux/kernel.h>
9 #include <linux/memory.h>
10 #include <asm/bug.h>
11 #include <asm/cacheflush.h>
12 #include <asm/text-patching.h>
13
arch_jump_label_transform_queue(struct jump_entry * entry,enum jump_label_type type)14 bool arch_jump_label_transform_queue(struct jump_entry *entry,
15 enum jump_label_type type)
16 {
17 void *addr = (void *)jump_entry_code(entry);
18 u32 insn;
19
20 if (type == JUMP_LABEL_JMP) {
21 long offset;
22
23 offset = jump_entry_target(entry) - jump_entry_code(entry);
24 /*
25 * The actual maximum range of the l.j instruction's offset is -134,217,728
26 * ~ 134,217,724 (sign 26-bit imm).
27 * For the original jump range, we need to right-shift N by 2 to obtain the
28 * instruction's offset.
29 */
30 WARN_ON_ONCE(offset < -134217728 || offset > 134217724);
31
32 /* 26bit imm mask */
33 offset = (offset >> 2) & 0x03ffffff;
34
35 insn = offset;
36 } else {
37 insn = OPENRISC_INSN_NOP;
38 }
39
40 if (early_boot_irqs_disabled)
41 copy_to_kernel_nofault(addr, &insn, sizeof(insn));
42 else
43 patch_insn_write(addr, insn);
44
45 return true;
46 }
47
arch_jump_label_transform_apply(void)48 void arch_jump_label_transform_apply(void)
49 {
50 kick_all_cpus_sync();
51 }
52