1 /* 2 * jump label x86 support 3 * 4 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com> 5 * 6 */ 7 #include <linux/jump_label.h> 8 #include <linux/memory.h> 9 #include <linux/uaccess.h> 10 #include <linux/module.h> 11 #include <linux/list.h> 12 #include <linux/jhash.h> 13 #include <linux/cpu.h> 14 #include <asm/kprobes.h> 15 #include <asm/alternative.h> 16 17 #ifdef HAVE_JUMP_LABEL 18 19 union jump_code_union { 20 char code[JUMP_LABEL_NOP_SIZE]; 21 struct { 22 char jump; 23 int offset; 24 } __attribute__((packed)); 25 }; 26 27 static void __jump_label_transform(struct jump_entry *entry, 28 enum jump_label_type type, 29 void *(*poker)(void *, const void *, size_t)) 30 { 31 union jump_code_union code; 32 33 if (type == JUMP_LABEL_ENABLE) { 34 code.jump = 0xe9; 35 code.offset = entry->target - 36 (entry->code + JUMP_LABEL_NOP_SIZE); 37 } else 38 memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE); 39 40 (*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE); 41 } 42 43 void arch_jump_label_transform(struct jump_entry *entry, 44 enum jump_label_type type) 45 { 46 get_online_cpus(); 47 mutex_lock(&text_mutex); 48 __jump_label_transform(entry, type, text_poke_smp); 49 mutex_unlock(&text_mutex); 50 put_online_cpus(); 51 } 52 53 __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, 54 enum jump_label_type type) 55 { 56 __jump_label_transform(entry, type, text_poke_early); 57 } 58 59 #endif 60