| 1 | // REQUIRES: native-run |
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| 2 | // RUN: %clang_builtins %s %librt -o %t && %run_nomprotect %t |
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| 3 | // REQUIRES: librt_has_enable_execute_stack |
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| 4 | |
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| 5 | #include <stdio.h> |
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| 6 | #include <string.h> |
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| 7 | #include <stdint.h> |
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| 8 | extern void __clear_cache(void* start, void* end); |
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| 9 | extern void __enable_execute_stack(void* addr); |
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| 10 | |
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| 11 | typedef int (*pfunc)(void); |
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| 12 | |
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| 13 | #ifdef __arm64ec__ |
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| 14 | // On ARM64EC, we need the x86_64 version of this function, but the compiler |
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| 15 | // would normally generate the AArch64 variant, so we hardcode it here. |
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| 16 | static char func1[] = { |
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| 17 | 0xb8, 0x01, 0x00, 0x00, 0x00, // movl $0x1, %eax |
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| 18 | 0xc3 // retq |
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| 19 | }; |
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| 20 | static char func2[] = { |
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| 21 | 0xb8, 0x02, 0x00, 0x00, 0x00, // movl $0x2, %eax |
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| 22 | 0xc3 // retq |
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| 23 | }; |
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| 24 | #else |
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| 25 | // Make these static to avoid ILT jumps for incremental linking on Windows. |
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| 26 | static int func1() { return 1; } |
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| 27 | static int func2() { return 2; } |
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| 28 | #endif |
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| 29 | |
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| 30 | void *__attribute__((noinline)) |
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| 31 | memcpy_f(void *dst, const void *src, size_t n) { |
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| 32 | // ARM and MIPS naturally align functions, but use the LSB for ISA selection |
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| 33 | // (THUMB, MIPS16/uMIPS respectively). Ensure that the ISA bit is ignored in |
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| 34 | // the memcpy |
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| 35 | #if defined(__arm__) || defined(__mips__) |
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| 36 | return (void *)((uintptr_t)memcpy(dst, (void *)((uintptr_t)src & ~1), n) | |
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| 37 | ((uintptr_t)src & 1)); |
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| 38 | #else |
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| 39 | return memcpy(dest: dst, src: (void *)((uintptr_t)src), n: n); |
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| 40 | #endif |
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| 41 | } |
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| 42 | |
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| 43 | int main() |
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| 44 | { |
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| 45 | #if defined(__ve__) |
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| 46 | unsigned char execution_buffer[128] __attribute__((__aligned__(8))); |
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| 47 | #else |
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| 48 | unsigned char execution_buffer[128]; |
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| 49 | #endif |
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| 50 | // mark stack page containing execution_buffer to be executable |
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| 51 | __enable_execute_stack(addr: execution_buffer); |
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| 52 | |
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| 53 | // verify you can copy and execute a function |
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| 54 | pfunc f1 = (pfunc)memcpy_f(dst: execution_buffer, src: func1, n: 128); |
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| 55 | __clear_cache(start: execution_buffer, end: &execution_buffer[128]); |
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| 56 | printf(format: "f1: %p\n" , f1); |
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| 57 | if ((*f1)() != 1) |
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| 58 | return 1; |
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| 59 | |
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| 60 | // verify you can overwrite a function with another |
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| 61 | pfunc f2 = (pfunc)memcpy_f(dst: execution_buffer, src: func2, n: 128); |
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| 62 | __clear_cache(start: execution_buffer, end: &execution_buffer[128]); |
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| 63 | if ((*f2)() != 2) |
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| 64 | return 1; |
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| 65 | |
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| 66 | return 0; |
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| 67 | } |
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| 68 | |
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