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