1// SPDX-License-Identifier: GPL-2.0-only
2
3#include <linux/jump_label.h>
4#include <linux/kernel.h>
5#include <linux/memory.h>
6#include <linux/mutex.h>
7#include <linux/uaccess.h>
8#include <asm/cacheflush.h>
9
10#define NOP32_HI	0xc400
11#define NOP32_LO	0x4820
12#define BSR_LINK	0xe000
13
14void arch_jump_label_transform(struct jump_entry *entry,
15			       enum jump_label_type type)
16{
17	unsigned long addr = jump_entry_code(entry);
18	u16 insn[2];
19	int ret = 0;
20
21	if (type == JUMP_LABEL_JMP) {
22		long offset = jump_entry_target(entry) - jump_entry_code(entry);
23
24		if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
25			return;
26
27		offset = offset >> 1;
28
29		insn[0] = BSR_LINK |
30			((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
31		insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
32	} else {
33		insn[0] = NOP32_HI;
34		insn[1] = NOP32_LO;
35	}
36
37	ret = copy_to_kernel_nofault((void *)addr, insn, 4);
38	WARN_ON(ret);
39
40	flush_icache_range(addr, addr + 4);
41}
42
43void arch_jump_label_transform_static(struct jump_entry *entry,
44				      enum jump_label_type type)
45{
46	/*
47	 * We use the same instructions in the arch_static_branch and
48	 * arch_static_branch_jump inline functions, so there's no
49	 * need to patch them up here.
50	 * The core will call arch_jump_label_transform  when those
51	 * instructions need to be replaced.
52	 */
53	arch_jump_label_transform(entry, type);
54}
55