1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (C) 2019 Helge Deller <deller@gmx.de>
5 * Based on arch/arm64/kernel/jump_label.c
7 #include <linux/kernel.h>
8 #include <linux/jump_label.h>
10 #include <asm/alternative.h>
11 #include <asm/patch.h>
13 static inline int reassemble_17(int as17)
15 return (((as17 & 0x10000) >> 16) |
16 ((as17 & 0x0f800) << 5) |
17 ((as17 & 0x00400) >> 8) |
18 ((as17 & 0x003ff) << 3));
21 void arch_jump_label_transform(struct jump_entry *entry,
22 enum jump_label_type type)
24 void *addr = (void *)jump_entry_code(entry);
27 if (type == JUMP_LABEL_JMP) {
28 void *target = (void *)jump_entry_target(entry);
29 int distance = target - addr;
31 * Encode the PA1.1 "b,n" instruction with a 17-bit
32 * displacement. In case we hit the BUG(), we could use
33 * another branch instruction with a 22-bit displacement on
34 * 64-bit CPUs instead. But this seems sufficient for now.
37 BUG_ON(distance > 262143 || distance < -262144);
38 insn = 0xe8000002 | reassemble_17(distance >> 2);
43 patch_text(addr, insn);