1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2020 Emil Renner Berthing
4 *
5 * Based on arch/arm64/kernel/jump_label.c
6 */
7 #include <linux/jump_label.h>
8 #include <linux/kernel.h>
9 #include <linux/memory.h>
10 #include <linux/mutex.h>
11 #include <asm/bug.h>
12 #include <asm/cacheflush.h>
13 #include <asm/patch.h>
14
15 #define RISCV_INSN_NOP 0x00000013U
16 #define RISCV_INSN_JAL 0x0000006fU
17
18 bool arch_jump_label_transform_queue(struct jump_entry *entry,
19 enum jump_label_type type)
20 {
21 void *addr = (void *)jump_entry_code(entry);
22 u32 insn;
23
24 if (type == JUMP_LABEL_JMP) {
25 long offset = jump_entry_target(entry) - jump_entry_code(entry);
26
27 if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
28 return true;
29
30 insn = RISCV_INSN_JAL |
31 (((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
32 (((u32)offset & GENMASK(11, 11)) << (20 - 11)) |
33 (((u32)offset & GENMASK(10, 1)) << (21 - 1)) |
34 (((u32)offset & GENMASK(20, 20)) << (31 - 20));
35 } else {
36 insn = RISCV_INSN_NOP;
37 }
38
39 mutex_lock(&text_mutex);
40 patch_insn_write(addr, &insn, sizeof(insn));
41 mutex_unlock(&text_mutex);
42
43 return true;
44 }
45
46 void arch_jump_label_transform_apply(void)
47 {
48 flush_icache_all();
49 }
50
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