55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
// REQUIRES: native-run
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// RUN: %clang_builtins %s %librt -o %t && %run_nomprotect %t
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// REQUIRES: librt_has_enable_execute_stack
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#include <stdio.h>
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#include <string.h>
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#include <stdint.h>
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extern void __clear_cache(void* start, void* end);
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extern void __enable_execute_stack(void* addr);
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typedef int (*pfunc)(void);
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// Make these static to avoid ILT jumps for incremental linking on Windows.
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static int func1() { return 1; }
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static int func2() { return 2; }
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void *__attribute__((noinline))
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memcpy_f(void *dst, const void *src, size_t n) {
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// ARM and MIPS naturally align functions, but use the LSB for ISA selection
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// (THUMB, MIPS16/uMIPS respectively). Ensure that the ISA bit is ignored in
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// the memcpy
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#if defined(__arm__) || defined(__mips__)
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return (void *)((uintptr_t)memcpy(dst, (void *)((uintptr_t)src & ~1), n) |
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((uintptr_t)src & 1));
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#else
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return memcpy(dst, (void *)((uintptr_t)src), n);
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#endif
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}
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int main()
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{
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#if defined(__ve__)
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unsigned char execution_buffer[128] __attribute__((__aligned__(8)));
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#else
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unsigned char execution_buffer[128];
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#endif
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// mark stack page containing execution_buffer to be executable
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__enable_execute_stack(execution_buffer);
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// verify you can copy and execute a function
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pfunc f1 = (pfunc)memcpy_f(execution_buffer, func1, 128);
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__clear_cache(execution_buffer, &execution_buffer[128]);
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printf("f1: %p\n", f1);
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if ((*f1)() != 1)
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return 1;
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// verify you can overwrite a function with another
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pfunc f2 = (pfunc)memcpy_f(execution_buffer, func2, 128);
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__clear_cache(execution_buffer, &execution_buffer[128]);
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if ((*f2)() != 2)
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return 1;
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return 0;
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}
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