| 1 | // SPDX-License-Identifier: GPL-2.0-only |
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| 2 | /* |
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| 3 | * rodata_test.c: functional test for mark_rodata_ro function |
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| 4 | * |
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| 5 | * (C) Copyright 2008 Intel Corporation |
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| 6 | * Author: Arjan van de Ven <arjan@linux.intel.com> |
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| 7 | */ |
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| 8 | #define pr_fmt(fmt) "rodata_test: " fmt |
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| 9 | |
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| 10 | #include <linux/rodata_test.h> |
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| 11 | #include <linux/uaccess.h> |
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| 12 | #include <linux/mm.h> |
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| 13 | #include <asm/sections.h> |
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| 14 | |
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| 15 | static const int rodata_test_data = 0xC3; |
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| 16 | |
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| 17 | void rodata_test(void) |
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| 18 | { |
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| 19 | int zero = 0; |
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| 20 | |
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| 21 | /* test 1: read the value */ |
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| 22 | /* If this test fails, some previous testrun has clobbered the state */ |
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| 23 | if (!rodata_test_data) { |
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| 24 | pr_err("test 1 fails (start data)\n" ); |
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| 25 | return; |
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| 26 | } |
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| 27 | |
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| 28 | /* test 2: write to the variable; this should fault */ |
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| 29 | if (!copy_to_kernel_nofault(dst: (void *)&rodata_test_data, |
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| 30 | src: (void *)&zero, size: sizeof(zero))) { |
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| 31 | pr_err("test data was not read only\n" ); |
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| 32 | return; |
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| 33 | } |
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| 34 | |
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| 35 | /* test 3: check the value hasn't changed */ |
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| 36 | if (rodata_test_data == zero) { |
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| 37 | pr_err("test data was changed\n" ); |
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| 38 | return; |
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| 39 | } |
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| 40 | |
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| 41 | /* test 4: check if the rodata section is PAGE_SIZE aligned */ |
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| 42 | if (!PAGE_ALIGNED(__start_rodata)) { |
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| 43 | pr_err("start of .rodata is not page size aligned\n" ); |
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| 44 | return; |
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| 45 | } |
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| 46 | if (!PAGE_ALIGNED(__end_rodata)) { |
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| 47 | pr_err("end of .rodata is not page size aligned\n" ); |
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| 48 | return; |
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| 49 | } |
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| 50 | |
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| 51 | pr_info("all tests were successful\n" ); |
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| 52 | } |
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| 53 | |
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