projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 620a53d5 SS |
1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* | |
| 3 | * functions to patch RO kernel text during runtime | |
| 4 | * | |
| 5 | * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org> | |
| 6 | */ | |
| 7 | ||
| 8 | #include <linux/kernel.h> | |
| 9 | #include <linux/spinlock.h> | |
| 10 | #include <linux/kprobes.h> | |
| 11 | #include <linux/mm.h> | |
| 12 | #include <linux/stop_machine.h> | |
| 13 | ||
| 14 | #include <asm/cacheflush.h> | |
| 15 | #include <asm/fixmap.h> | |
| 16 | #include <asm/patch.h> | |
| 17 | ||
| 18 | struct patch { | |
| 19 | void *addr; | |
| 20 | unsigned int insn; | |
| 21 | }; | |
| 22 | ||
| ea5a8c62 | 23 | static void __kprobes *patch_map(void *addr, int fixmap) |
| 620a53d5 SS |
24 | { |
| 25 | unsigned long uintaddr = (uintptr_t) addr; | |
| 26 | bool module = !core_kernel_text(uintaddr); | |
| 27 | struct page *page; | |
| 28 | ||
| 29 | if (module && IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) | |
| 30 | page = vmalloc_to_page(addr); | |
| 31 | else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) | |
| 32 | page = virt_to_page(addr); | |
| 33 | else | |
| 34 | return addr; | |
| 35 | ||
| 36 | set_fixmap(fixmap, page_to_phys(page)); | |
| 37 | ||
| 38 | return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); | |
| 39 | } | |
| 40 | ||
| ea5a8c62 | 41 | static void __kprobes patch_unmap(int fixmap) |
| 620a53d5 SS |
42 | { |
| 43 | clear_fixmap(fixmap); | |
| 44 | } | |
| 45 | ||
| 46 | void __kprobes __patch_text(void *addr, unsigned int insn) | |
| 47 | { | |
| 620a53d5 SS |
48 | void *waddr = addr; |
| 49 | int size; | |
| 50 | ||
| ea5a8c62 | 51 | waddr = patch_map(addr, FIX_TEXT_POKE0); |
| 620a53d5 SS |
52 | *(u32 *)waddr = insn; |
| 53 | size = sizeof(u32); | |
| 54 | flush_kernel_vmap_range(waddr, size); | |
| ea5a8c62 | 55 | patch_unmap(FIX_TEXT_POKE0); |
| 620a53d5 SS |
56 | flush_icache_range((uintptr_t)(addr), |
| 57 | (uintptr_t)(addr) + size); | |
| 58 | } | |
| 59 | ||
| 60 | static int __kprobes patch_text_stop_machine(void *data) | |
| 61 | { | |
| 62 | struct patch *patch = data; | |
| 63 | ||
| 64 | __patch_text(patch->addr, patch->insn); | |
| 65 | ||
| 66 | return 0; | |
| 67 | } | |
| 68 | ||
| 69 | void __kprobes patch_text(void *addr, unsigned int insn) | |
| 70 | { | |
| 71 | struct patch patch = { | |
| 72 | .addr = addr, | |
| 73 | .insn = insn, | |
| 74 | }; | |
| 75 | ||
| 76 | stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL); | |
| 77 | } |