162217bebSHelge Deller // SPDX-License-Identifier: GPL-2.0+ 262217bebSHelge Deller /* 362217bebSHelge Deller * Copyright (C) 2019 Helge Deller <deller@gmx.de> 462217bebSHelge Deller * 562217bebSHelge Deller * Based on arch/arm64/kernel/jump_label.c 662217bebSHelge Deller */ 762217bebSHelge Deller #include <linux/kernel.h> 862217bebSHelge Deller #include <linux/jump_label.h> 962217bebSHelge Deller #include <linux/bug.h> 1062217bebSHelge Deller #include <asm/alternative.h> 1162217bebSHelge Deller #include <asm/patch.h> 1262217bebSHelge Deller reassemble_17(int as17)1362217bebSHelge Dellerstatic inline int reassemble_17(int as17) 1462217bebSHelge Deller { 1562217bebSHelge Deller return (((as17 & 0x10000) >> 16) | 1662217bebSHelge Deller ((as17 & 0x0f800) << 5) | 1762217bebSHelge Deller ((as17 & 0x00400) >> 8) | 1862217bebSHelge Deller ((as17 & 0x003ff) << 3)); 1962217bebSHelge Deller } 2062217bebSHelge Deller arch_jump_label_transform(struct jump_entry * entry,enum jump_label_type type)2162217bebSHelge Dellervoid arch_jump_label_transform(struct jump_entry *entry, 2262217bebSHelge Deller enum jump_label_type type) 2362217bebSHelge Deller { 2462217bebSHelge Deller void *addr = (void *)jump_entry_code(entry); 2562217bebSHelge Deller u32 insn; 2662217bebSHelge Deller 2762217bebSHelge Deller if (type == JUMP_LABEL_JMP) { 2862217bebSHelge Deller void *target = (void *)jump_entry_target(entry); 2962217bebSHelge Deller int distance = target - addr; 3062217bebSHelge Deller /* 3162217bebSHelge Deller * Encode the PA1.1 "b,n" instruction with a 17-bit 3262217bebSHelge Deller * displacement. In case we hit the BUG(), we could use 3362217bebSHelge Deller * another branch instruction with a 22-bit displacement on 3462217bebSHelge Deller * 64-bit CPUs instead. But this seems sufficient for now. 3562217bebSHelge Deller */ 3662217bebSHelge Deller distance -= 8; 3762217bebSHelge Deller BUG_ON(distance > 262143 || distance < -262144); 3862217bebSHelge Deller insn = 0xe8000002 | reassemble_17(distance >> 2); 3962217bebSHelge Deller } else { 4062217bebSHelge Deller insn = INSN_NOP; 4162217bebSHelge Deller } 4262217bebSHelge Deller 4362217bebSHelge Deller patch_text(addr, insn); 4462217bebSHelge Deller } 45