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| 2 | |
| 3 | * Two translation units with a same-named static, placed so that the linker
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| 4 | * puts them in the opposite order to the one they appear in the symbol table.
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| 5 | *
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| 6 | * VARSEC selects the section the static lands in. Linking with
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| 7 | * --sort-section=name then orders them alphabetically rather than by object
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| 8 | * order, so the first symbol in the symbol table ends up at the *higher*
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| 9 | * address. That is the whole point: counting symbol table order and reading
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| 10 | * the linked image's addresses now give different answers, which is what makes
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| 11 | * it possible to tell which one klp diff used.
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| 12 | *
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| 13 | * Only use_a is patched, so exactly one sympos is emitted and there is nothing
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| 14 | * to attribute.
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| 15 |
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| 16 |
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| 17 | #ifndef FUNC_NAME
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| 18 | #define FUNC_NAME use_a
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| 19 | #endif
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| 20 | #ifndef VARSEC
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| 21 | #define VARSEC ".data.mmm"
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| 22 | #endif
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| 23 |
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| 24 | #ifndef NO_MODINFO
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| 25 | static const char __modinfo[]
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| 26 | __attribute__((section(".modinfo"), used, aligned(1))) = "\0name=vmlinux";
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| 27 | #endif
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| 28 |
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| 29 |
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| 30 | static volatile int dup_counter __attribute__((section(VARSEC))) = 1;
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| 31 |
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| 32 | int FUNC_NAME(int x)
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| 33 | {
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| 34 | dup_counter += x;
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| 35 | #ifdef PATCHED
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| 36 | return dup_counter + 1;
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| 37 | #else
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| 38 | return dup_counter;
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| 39 | #endif
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| 40 | }
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