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6 | 6 | #include <linux/spinlock.h>
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7 | 7 | #include <linux/mm.h>
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8 | 8 | #include <linux/memory.h>
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| 9 | +#include <linux/string.h> |
9 | 10 | #include <linux/uaccess.h>
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10 | 11 | #include <linux/stop_machine.h>
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11 | 12 | #include <asm/kprobes.h>
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@@ -53,6 +54,39 @@ static void patch_unmap(int fixmap)
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53 | 54 | }
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54 | 55 | NOKPROBE_SYMBOL(patch_unmap);
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55 | 56 |
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| 57 | +static int __patch_insn_set(void *addr, u8 c, size_t len) |
| 58 | +{ |
| 59 | + void *waddr = addr; |
| 60 | + bool across_pages = (((uintptr_t)addr & ~PAGE_MASK) + len) > PAGE_SIZE; |
| 61 | + |
| 62 | + /* |
| 63 | + * Only two pages can be mapped at a time for writing. |
| 64 | + */ |
| 65 | + if (len + offset_in_page(addr) > 2 * PAGE_SIZE) |
| 66 | + return -EINVAL; |
| 67 | + /* |
| 68 | + * Before reaching here, it was expected to lock the text_mutex |
| 69 | + * already, so we don't need to give another lock here and could |
| 70 | + * ensure that it was safe between each cores. |
| 71 | + */ |
| 72 | + lockdep_assert_held(&text_mutex); |
| 73 | + |
| 74 | + if (across_pages) |
| 75 | + patch_map(addr + PAGE_SIZE, FIX_TEXT_POKE1); |
| 76 | + |
| 77 | + waddr = patch_map(addr, FIX_TEXT_POKE0); |
| 78 | + |
| 79 | + memset(waddr, c, len); |
| 80 | + |
| 81 | + patch_unmap(FIX_TEXT_POKE0); |
| 82 | + |
| 83 | + if (across_pages) |
| 84 | + patch_unmap(FIX_TEXT_POKE1); |
| 85 | + |
| 86 | + return 0; |
| 87 | +} |
| 88 | +NOKPROBE_SYMBOL(__patch_insn_set); |
| 89 | + |
56 | 90 | static int __patch_insn_write(void *addr, const void *insn, size_t len)
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57 | 91 | {
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58 | 92 | void *waddr = addr;
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@@ -95,13 +129,56 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len)
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95 | 129 | }
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96 | 130 | NOKPROBE_SYMBOL(__patch_insn_write);
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97 | 131 | #else
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| 132 | +static int __patch_insn_set(void *addr, u8 c, size_t len) |
| 133 | +{ |
| 134 | + memset(addr, c, len); |
| 135 | + |
| 136 | + return 0; |
| 137 | +} |
| 138 | +NOKPROBE_SYMBOL(__patch_insn_set); |
| 139 | + |
98 | 140 | static int __patch_insn_write(void *addr, const void *insn, size_t len)
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99 | 141 | {
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100 | 142 | return copy_to_kernel_nofault(addr, insn, len);
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101 | 143 | }
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102 | 144 | NOKPROBE_SYMBOL(__patch_insn_write);
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103 | 145 | #endif /* CONFIG_MMU */
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104 | 146 |
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| 147 | +static int patch_insn_set(void *addr, u8 c, size_t len) |
| 148 | +{ |
| 149 | + size_t patched = 0; |
| 150 | + size_t size; |
| 151 | + int ret = 0; |
| 152 | + |
| 153 | + /* |
| 154 | + * __patch_insn_set() can only work on 2 pages at a time so call it in a |
| 155 | + * loop with len <= 2 * PAGE_SIZE. |
| 156 | + */ |
| 157 | + while (patched < len && !ret) { |
| 158 | + size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched); |
| 159 | + ret = __patch_insn_set(addr + patched, c, size); |
| 160 | + |
| 161 | + patched += size; |
| 162 | + } |
| 163 | + |
| 164 | + return ret; |
| 165 | +} |
| 166 | +NOKPROBE_SYMBOL(patch_insn_set); |
| 167 | + |
| 168 | +int patch_text_set_nosync(void *addr, u8 c, size_t len) |
| 169 | +{ |
| 170 | + u32 *tp = addr; |
| 171 | + int ret; |
| 172 | + |
| 173 | + ret = patch_insn_set(tp, c, len); |
| 174 | + |
| 175 | + if (!ret) |
| 176 | + flush_icache_range((uintptr_t)tp, (uintptr_t)tp + len); |
| 177 | + |
| 178 | + return ret; |
| 179 | +} |
| 180 | +NOKPROBE_SYMBOL(patch_text_set_nosync); |
| 181 | + |
105 | 182 | static int patch_insn_write(void *addr, const void *insn, size_t len)
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106 | 183 | {
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107 | 184 | size_t patched = 0;
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