1 #include <linux/kernel.h> 2 #include <linux/kprobes.h> 3 #include <linux/stop_machine.h> 4 5 #include <asm/cacheflush.h> 6 #include <asm/smp_plat.h> 7 #include <asm/opcodes.h> 8 9 #include "patch.h" 10 11 struct patch { 12 void *addr; 13 unsigned int insn; 14 }; 15 16 void __kprobes __patch_text(void *addr, unsigned int insn) 17 { 18 bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); 19 int size; 20 21 if (thumb2 && __opcode_is_thumb16(insn)) { 22 *(u16 *)addr = __opcode_to_mem_thumb16(insn); 23 size = sizeof(u16); 24 } else if (thumb2 && ((uintptr_t)addr & 2)) { 25 u16 first = __opcode_thumb32_first(insn); 26 u16 second = __opcode_thumb32_second(insn); 27 u16 *addrh = addr; 28 29 addrh[0] = __opcode_to_mem_thumb16(first); 30 addrh[1] = __opcode_to_mem_thumb16(second); 31 32 size = sizeof(u32); 33 } else { 34 if (thumb2) 35 insn = __opcode_to_mem_thumb32(insn); 36 else 37 insn = __opcode_to_mem_arm(insn); 38 39 *(u32 *)addr = insn; 40 size = sizeof(u32); 41 } 42 43 flush_icache_range((uintptr_t)(addr), 44 (uintptr_t)(addr) + size); 45 } 46 47 static int __kprobes patch_text_stop_machine(void *data) 48 { 49 struct patch *patch = data; 50 51 __patch_text(patch->addr, patch->insn); 52 53 return 0; 54 } 55 56 void __kprobes patch_text(void *addr, unsigned int insn) 57 { 58 struct patch patch = { 59 .addr = addr, 60 .insn = insn, 61 }; 62 63 if (cache_ops_need_broadcast()) { 64 stop_machine(patch_text_stop_machine, &patch, cpu_online_mask); 65 } else { 66 bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL) 67 && __opcode_is_thumb32(insn) 68 && ((uintptr_t)addr & 2); 69 70 if (straddles_word) 71 stop_machine(patch_text_stop_machine, &patch, NULL); 72 else 73 __patch_text(addr, insn); 74 } 75 } 76