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141 lines
3.7 KiB
141 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* KCSAN short boot-time selftests. |
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* |
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* Copyright (C) 2019, Google LLC. |
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*/ |
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#define pr_fmt(fmt) "kcsan: " fmt |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/printk.h> |
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#include <linux/random.h> |
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#include <linux/types.h> |
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#include "encoding.h" |
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#define ITERS_PER_TEST 2000 |
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/* Test requirements. */ |
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static bool test_requires(void) |
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{ |
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/* random should be initialized for the below tests */ |
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return prandom_u32() + prandom_u32() != 0; |
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} |
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/* |
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* Test watchpoint encode and decode: check that encoding some access's info, |
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* and then subsequent decode preserves the access's info. |
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*/ |
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static bool test_encode_decode(void) |
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{ |
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int i; |
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for (i = 0; i < ITERS_PER_TEST; ++i) { |
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size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1; |
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bool is_write = !!prandom_u32_max(2); |
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unsigned long addr; |
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prandom_bytes(&addr, sizeof(addr)); |
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if (addr < PAGE_SIZE) |
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addr = PAGE_SIZE; |
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if (WARN_ON(!check_encodable(addr, size))) |
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return false; |
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/* Encode and decode */ |
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{ |
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const long encoded_watchpoint = |
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encode_watchpoint(addr, size, is_write); |
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unsigned long verif_masked_addr; |
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size_t verif_size; |
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bool verif_is_write; |
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/* Check special watchpoints */ |
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if (WARN_ON(decode_watchpoint( |
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INVALID_WATCHPOINT, &verif_masked_addr, |
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&verif_size, &verif_is_write))) |
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return false; |
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if (WARN_ON(decode_watchpoint( |
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CONSUMED_WATCHPOINT, &verif_masked_addr, |
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&verif_size, &verif_is_write))) |
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return false; |
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/* Check decoding watchpoint returns same data */ |
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if (WARN_ON(!decode_watchpoint( |
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encoded_watchpoint, &verif_masked_addr, |
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&verif_size, &verif_is_write))) |
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return false; |
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if (WARN_ON(verif_masked_addr != |
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(addr & WATCHPOINT_ADDR_MASK))) |
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goto fail; |
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if (WARN_ON(verif_size != size)) |
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goto fail; |
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if (WARN_ON(is_write != verif_is_write)) |
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goto fail; |
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continue; |
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fail: |
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pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n", |
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__func__, is_write ? "write" : "read", size, |
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addr, encoded_watchpoint, |
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verif_is_write ? "write" : "read", verif_size, |
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verif_masked_addr); |
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return false; |
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} |
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} |
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return true; |
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} |
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/* Test access matching function. */ |
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static bool test_matching_access(void) |
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{ |
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if (WARN_ON(!matching_access(10, 1, 10, 1))) |
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return false; |
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if (WARN_ON(!matching_access(10, 2, 11, 1))) |
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return false; |
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if (WARN_ON(!matching_access(10, 1, 9, 2))) |
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return false; |
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if (WARN_ON(matching_access(10, 1, 11, 1))) |
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return false; |
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if (WARN_ON(matching_access(9, 1, 10, 1))) |
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return false; |
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/* |
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* An access of size 0 could match another access, as demonstrated here. |
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* Rather than add more comparisons to 'matching_access()', which would |
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* end up in the fast-path for *all* checks, check_access() simply |
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* returns for all accesses of size 0. |
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*/ |
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if (WARN_ON(!matching_access(8, 8, 12, 0))) |
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return false; |
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return true; |
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} |
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static int __init kcsan_selftest(void) |
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{ |
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int passed = 0; |
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int total = 0; |
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#define RUN_TEST(do_test) \ |
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do { \ |
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++total; \ |
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if (do_test()) \ |
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++passed; \ |
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else \ |
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pr_err("selftest: " #do_test " failed"); \ |
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} while (0) |
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RUN_TEST(test_requires); |
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RUN_TEST(test_encode_decode); |
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RUN_TEST(test_matching_access); |
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pr_info("selftest: %d/%d tests passed\n", passed, total); |
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if (passed != total) |
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panic("selftests failed"); |
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return 0; |
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} |
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postcore_initcall(kcsan_selftest);
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