1 #include <linux/kernel.h> 2 #include <linux/spinlock.h> 3 #include <linux/kprobes.h> 4 #include <linux/mm.h> 5 #include <linux/stop_machine.h> 6 7 #include <asm/cacheflush.h> 8 #include <asm/fixmap.h> 9 #include <asm/smp_plat.h> 10 #include <asm/opcodes.h> 11 #include <asm/patch.h> 12 13 struct patch { 14 void *addr; 15 unsigned int insn; 16 }; 17 18 static DEFINE_SPINLOCK(patch_lock); 19 20 static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags) 21 __acquires(&patch_lock) 22 { 23 unsigned int uintaddr = (uintptr_t) addr; 24 bool module = !core_kernel_text(uintaddr); 25 struct page *page; 26 27 if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX)) 28 page = vmalloc_to_page(addr); 29 else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA)) 30 page = virt_to_page(addr); 31 else 32 return addr; 33 34 if (flags) 35 spin_lock_irqsave(&patch_lock, *flags); 36 else 37 __acquire(&patch_lock); 38 39 set_fixmap(fixmap, page_to_phys(page)); 40 41 return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); 42 } 43 44 static void __kprobes patch_unmap(int fixmap, unsigned long *flags) 45 __releases(&patch_lock) 46 { 47 clear_fixmap(fixmap); 48 49 if (flags) 50 spin_unlock_irqrestore(&patch_lock, *flags); 51 else 52 __release(&patch_lock); 53 } 54 55 void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap) 56 { 57 bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL); 58 unsigned int uintaddr = (uintptr_t) addr; 59 bool twopage = false; 60 unsigned long flags; 61 void *waddr = addr; 62 int size; 63 64 if (remap) 65 waddr = patch_map(addr, FIX_TEXT_POKE0, &flags); 66 else 67 __acquire(&patch_lock); 68 69 if (thumb2 && __opcode_is_thumb16(insn)) { 70 *(u16 *)waddr = __opcode_to_mem_thumb16(insn); 71 size = sizeof(u16); 72 } else if (thumb2 && (uintaddr & 2)) { 73 u16 first = __opcode_thumb32_first(insn); 74 u16 second = __opcode_thumb32_second(insn); 75 u16 *addrh0 = waddr; 76 u16 *addrh1 = waddr + 2; 77 78 twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2; 79 if (twopage && remap) 80 addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL); 81 82 *addrh0 = __opcode_to_mem_thumb16(first); 83 *addrh1 = __opcode_to_mem_thumb16(second); 84 85 if (twopage && addrh1 != addr + 2) { 86 flush_kernel_vmap_range(addrh1, 2); 87 patch_unmap(FIX_TEXT_POKE1, NULL); 88 } 89 90 size = sizeof(u32); 91 } else { 92 if (thumb2) 93 insn = __opcode_to_mem_thumb32(insn); 94 else 95 insn = __opcode_to_mem_arm(insn); 96 97 *(u32 *)waddr = insn; 98 size = sizeof(u32); 99 } 100 101 if (waddr != addr) { 102 flush_kernel_vmap_range(waddr, twopage ? size / 2 : size); 103 patch_unmap(FIX_TEXT_POKE0, &flags); 104 } else 105 __release(&patch_lock); 106 107 flush_icache_range((uintptr_t)(addr), 108 (uintptr_t)(addr) + size); 109 } 110 111 static int __kprobes patch_text_stop_machine(void *data) 112 { 113 struct patch *patch = data; 114 115 __patch_text(patch->addr, patch->insn); 116 117 return 0; 118 } 119 120 void __kprobes patch_text(void *addr, unsigned int insn) 121 { 122 struct patch patch = { 123 .addr = addr, 124 .insn = insn, 125 }; 126 127 stop_machine(patch_text_stop_machine, &patch, NULL); 128 } 129