| 1 | #include <stdio.h> |
|---|---|
| 2 | |
| 3 | // For the test case, we really want the the layout of this binary |
| 4 | // to be: |
| 5 | // |
| 6 | // foo() |
| 7 | // bar() - 4096 bytes of nop's |
| 8 | // main() |
| 9 | // "HI" string |
| 10 | // |
| 11 | // in reality getting this layout from the compiler and linker |
| 12 | // is a crapshoot, so I have yaml's checked in of the correct |
| 13 | // layout. Recompiling from source may not get the needed |
| 14 | // binary layout. |
| 15 | |
| 16 | static int bar(); |
| 17 | static int foo() { return 5 + bar(); } |
| 18 | // A function of 4096 bytes, so when main() loads the |
| 19 | // address of foo() before this one, it has to subtract |
| 20 | // a 4096 page. |
| 21 | #define SIXTY_FOUR_BYTES_NOP \ |
| 22 | asm("nop"); \ |
| 23 | asm("nop"); \ |
| 24 | asm("nop"); \ |
| 25 | asm("nop"); \ |
| 26 | asm("nop"); \ |
| 27 | asm("nop"); \ |
| 28 | asm("nop"); \ |
| 29 | asm("nop"); \ |
| 30 | asm("nop"); \ |
| 31 | asm("nop"); \ |
| 32 | asm("nop"); \ |
| 33 | asm("nop"); \ |
| 34 | asm("nop"); \ |
| 35 | asm("nop"); \ |
| 36 | asm("nop"); \ |
| 37 | asm("nop"); |
| 38 | |
| 39 | static int bar() { |
| 40 | SIXTY_FOUR_BYTES_NOP; |
| 41 | SIXTY_FOUR_BYTES_NOP; |
| 42 | SIXTY_FOUR_BYTES_NOP; |
| 43 | SIXTY_FOUR_BYTES_NOP; |
| 44 | SIXTY_FOUR_BYTES_NOP; |
| 45 | SIXTY_FOUR_BYTES_NOP; |
| 46 | SIXTY_FOUR_BYTES_NOP; |
| 47 | SIXTY_FOUR_BYTES_NOP; |
| 48 | SIXTY_FOUR_BYTES_NOP; |
| 49 | SIXTY_FOUR_BYTES_NOP; |
| 50 | SIXTY_FOUR_BYTES_NOP; |
| 51 | SIXTY_FOUR_BYTES_NOP; |
| 52 | SIXTY_FOUR_BYTES_NOP; |
| 53 | SIXTY_FOUR_BYTES_NOP; |
| 54 | SIXTY_FOUR_BYTES_NOP; |
| 55 | SIXTY_FOUR_BYTES_NOP; |
| 56 | SIXTY_FOUR_BYTES_NOP; |
| 57 | SIXTY_FOUR_BYTES_NOP; |
| 58 | SIXTY_FOUR_BYTES_NOP; |
| 59 | SIXTY_FOUR_BYTES_NOP; |
| 60 | SIXTY_FOUR_BYTES_NOP; |
| 61 | SIXTY_FOUR_BYTES_NOP; |
| 62 | SIXTY_FOUR_BYTES_NOP; |
| 63 | SIXTY_FOUR_BYTES_NOP; |
| 64 | SIXTY_FOUR_BYTES_NOP; |
| 65 | SIXTY_FOUR_BYTES_NOP; |
| 66 | SIXTY_FOUR_BYTES_NOP; |
| 67 | SIXTY_FOUR_BYTES_NOP; |
| 68 | SIXTY_FOUR_BYTES_NOP; |
| 69 | SIXTY_FOUR_BYTES_NOP; |
| 70 | SIXTY_FOUR_BYTES_NOP; |
| 71 | SIXTY_FOUR_BYTES_NOP; |
| 72 | SIXTY_FOUR_BYTES_NOP; |
| 73 | SIXTY_FOUR_BYTES_NOP; |
| 74 | SIXTY_FOUR_BYTES_NOP; |
| 75 | SIXTY_FOUR_BYTES_NOP; |
| 76 | SIXTY_FOUR_BYTES_NOP; |
| 77 | SIXTY_FOUR_BYTES_NOP; |
| 78 | SIXTY_FOUR_BYTES_NOP; |
| 79 | SIXTY_FOUR_BYTES_NOP; |
| 80 | SIXTY_FOUR_BYTES_NOP; |
| 81 | SIXTY_FOUR_BYTES_NOP; |
| 82 | SIXTY_FOUR_BYTES_NOP; |
| 83 | SIXTY_FOUR_BYTES_NOP; |
| 84 | SIXTY_FOUR_BYTES_NOP; |
| 85 | SIXTY_FOUR_BYTES_NOP; |
| 86 | SIXTY_FOUR_BYTES_NOP; |
| 87 | SIXTY_FOUR_BYTES_NOP; |
| 88 | SIXTY_FOUR_BYTES_NOP; |
| 89 | SIXTY_FOUR_BYTES_NOP; |
| 90 | SIXTY_FOUR_BYTES_NOP; |
| 91 | SIXTY_FOUR_BYTES_NOP; |
| 92 | SIXTY_FOUR_BYTES_NOP; |
| 93 | SIXTY_FOUR_BYTES_NOP; |
| 94 | SIXTY_FOUR_BYTES_NOP; |
| 95 | SIXTY_FOUR_BYTES_NOP; |
| 96 | SIXTY_FOUR_BYTES_NOP; |
| 97 | SIXTY_FOUR_BYTES_NOP; |
| 98 | SIXTY_FOUR_BYTES_NOP; |
| 99 | SIXTY_FOUR_BYTES_NOP; |
| 100 | SIXTY_FOUR_BYTES_NOP; |
| 101 | SIXTY_FOUR_BYTES_NOP; |
| 102 | SIXTY_FOUR_BYTES_NOP; |
| 103 | SIXTY_FOUR_BYTES_NOP; |
| 104 | return 5; |
| 105 | } |
| 106 | int main() { |
| 107 | int (*f)(void) = foo; |
| 108 | puts(s: "HI"); |
| 109 | return f(); |
| 110 | } |
| 111 |