1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/bug.h> |
3 | #include <linux/kernel.h> |
4 | #include <asm/opcodes.h> |
5 | |
6 | static unsigned long __arm_gen_branch_thumb2(unsigned long pc, |
7 | unsigned long addr, bool link, |
8 | bool warn) |
9 | { |
10 | unsigned long s, j1, j2, i1, i2, imm10, imm11; |
11 | unsigned long first, second; |
12 | long offset; |
13 | |
14 | offset = (long)addr - (long)(pc + 4); |
15 | if (offset < -16777216 || offset > 16777214) { |
16 | WARN_ON_ONCE(warn); |
17 | return 0; |
18 | } |
19 | |
20 | s = (offset >> 24) & 0x1; |
21 | i1 = (offset >> 23) & 0x1; |
22 | i2 = (offset >> 22) & 0x1; |
23 | imm10 = (offset >> 12) & 0x3ff; |
24 | imm11 = (offset >> 1) & 0x7ff; |
25 | |
26 | j1 = (!i1) ^ s; |
27 | j2 = (!i2) ^ s; |
28 | |
29 | first = 0xf000 | (s << 10) | imm10; |
30 | second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11; |
31 | if (link) |
32 | second |= 1 << 14; |
33 | |
34 | return __opcode_thumb32_compose(first, second); |
35 | } |
36 | |
37 | static unsigned long __arm_gen_branch_arm(unsigned long pc, unsigned long addr, |
38 | bool link, bool warn) |
39 | { |
40 | unsigned long opcode = 0xea000000; |
41 | long offset; |
42 | |
43 | if (link) |
44 | opcode |= 1 << 24; |
45 | |
46 | offset = (long)addr - (long)(pc + 8); |
47 | if (unlikely(offset < -33554432 || offset > 33554428)) { |
48 | WARN_ON_ONCE(warn); |
49 | return 0; |
50 | } |
51 | |
52 | offset = (offset >> 2) & 0x00ffffff; |
53 | |
54 | return opcode | offset; |
55 | } |
56 | |
57 | unsigned long |
58 | __arm_gen_branch(unsigned long pc, unsigned long addr, bool link, bool warn) |
59 | { |
60 | if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) |
61 | return __arm_gen_branch_thumb2(pc, addr, link, warn); |
62 | else |
63 | return __arm_gen_branch_arm(pc, addr, link, warn); |
64 | } |
65 | |