1*62217bebSHelge Deller // SPDX-License-Identifier: GPL-2.0+ 2*62217bebSHelge Deller /* 3*62217bebSHelge Deller * Copyright (C) 2019 Helge Deller <deller@gmx.de> 4*62217bebSHelge Deller * 5*62217bebSHelge Deller * Based on arch/arm64/kernel/jump_label.c 6*62217bebSHelge Deller */ 7*62217bebSHelge Deller #include <linux/kernel.h> 8*62217bebSHelge Deller #include <linux/jump_label.h> 9*62217bebSHelge Deller #include <linux/bug.h> 10*62217bebSHelge Deller #include <asm/alternative.h> 11*62217bebSHelge Deller #include <asm/patch.h> 12*62217bebSHelge Deller reassemble_17(int as17)13*62217bebSHelge Dellerstatic inline int reassemble_17(int as17) 14*62217bebSHelge Deller { 15*62217bebSHelge Deller return (((as17 & 0x10000) >> 16) | 16*62217bebSHelge Deller ((as17 & 0x0f800) << 5) | 17*62217bebSHelge Deller ((as17 & 0x00400) >> 8) | 18*62217bebSHelge Deller ((as17 & 0x003ff) << 3)); 19*62217bebSHelge Deller } 20*62217bebSHelge Deller arch_jump_label_transform(struct jump_entry * entry,enum jump_label_type type)21*62217bebSHelge Dellervoid arch_jump_label_transform(struct jump_entry *entry, 22*62217bebSHelge Deller enum jump_label_type type) 23*62217bebSHelge Deller { 24*62217bebSHelge Deller void *addr = (void *)jump_entry_code(entry); 25*62217bebSHelge Deller u32 insn; 26*62217bebSHelge Deller 27*62217bebSHelge Deller if (type == JUMP_LABEL_JMP) { 28*62217bebSHelge Deller void *target = (void *)jump_entry_target(entry); 29*62217bebSHelge Deller int distance = target - addr; 30*62217bebSHelge Deller /* 31*62217bebSHelge Deller * Encode the PA1.1 "b,n" instruction with a 17-bit 32*62217bebSHelge Deller * displacement. In case we hit the BUG(), we could use 33*62217bebSHelge Deller * another branch instruction with a 22-bit displacement on 34*62217bebSHelge Deller * 64-bit CPUs instead. But this seems sufficient for now. 35*62217bebSHelge Deller */ 36*62217bebSHelge Deller distance -= 8; 37*62217bebSHelge Deller BUG_ON(distance > 262143 || distance < -262144); 38*62217bebSHelge Deller insn = 0xe8000002 | reassemble_17(distance >> 2); 39*62217bebSHelge Deller } else { 40*62217bebSHelge Deller insn = INSN_NOP; 41*62217bebSHelge Deller } 42*62217bebSHelge Deller 43*62217bebSHelge Deller patch_text(addr, insn); 44*62217bebSHelge Deller } 45