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
14 void 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
43 void 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
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.