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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | // SPDX-License-Identifier: GPL-2.0+ // // Copyright 2019, Michael Ellerman, IBM Corp. // // Test that out-of-bounds reads/writes behave as expected. #include <setjmp.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include "utils.h" // Old distros (Ubuntu 16.04 at least) don't define this #ifndef SEGV_BNDERR #define SEGV_BNDERR 3 #endif // 64-bit kernel is always here #define PAGE_OFFSET (0xcul << 60) static unsigned long kernel_virt_end; static volatile int fault_code; static volatile unsigned long fault_addr; static jmp_buf setjmp_env; static void segv_handler(int n, siginfo_t *info, void *ctxt_v) { fault_code = info->si_code; fault_addr = (unsigned long)info->si_addr; siglongjmp(setjmp_env, 1); } int bad_access(char *p, bool write) { char x; fault_code = 0; fault_addr = 0; if (sigsetjmp(setjmp_env, 1) == 0) { if (write) *p = 1; else x = *p; printf("Bad - no SEGV! (%c)\n", x); return 1; } // If we see MAPERR that means we took a page fault rather than an SLB // miss. We only expect to take page faults for addresses within the // valid kernel range. FAIL_IF(fault_code == SEGV_MAPERR && \ (fault_addr < PAGE_OFFSET || fault_addr >= kernel_virt_end)); FAIL_IF(fault_code != SEGV_MAPERR && fault_code != SEGV_BNDERR); return 0; } static int test(void) { unsigned long i, j, addr, region_shift, page_shift, page_size; struct sigaction sig; bool hash_mmu; sig = (struct sigaction) { .sa_sigaction = segv_handler, .sa_flags = SA_SIGINFO, }; FAIL_IF(sigaction(SIGSEGV, &sig, NULL) != 0); FAIL_IF(using_hash_mmu(&hash_mmu)); page_size = sysconf(_SC_PAGESIZE); if (page_size == (64 * 1024)) page_shift = 16; else page_shift = 12; if (page_size == (64 * 1024) || !hash_mmu) { region_shift = 52; // We have 7 512T regions (4 kernel linear, vmalloc, io, vmemmap) kernel_virt_end = PAGE_OFFSET + (7 * (512ul << 40)); } else if (page_size == (4 * 1024) && hash_mmu) { region_shift = 46; // We have 7 64T regions (4 kernel linear, vmalloc, io, vmemmap) kernel_virt_end = PAGE_OFFSET + (7 * (64ul << 40)); } else FAIL_IF(true); printf("Using %s MMU, PAGE_SIZE = %dKB start address 0x%016lx\n", hash_mmu ? "hash" : "radix", (1 << page_shift) >> 10, 1ul << region_shift); // This generates access patterns like: // 0x0010000000000000 // 0x0010000000010000 // 0x0010000000020000 // ... // 0x0014000000000000 // 0x0018000000000000 // 0x0020000000000000 // 0x0020000000010000 // 0x0020000000020000 // ... // 0xf400000000000000 // 0xf800000000000000 for (i = 1; i <= ((0xful << 60) >> region_shift); i++) { for (j = page_shift - 1; j < 60; j++) { unsigned long base, delta; base = i << region_shift; delta = 1ul << j; if (delta >= base) break; addr = (base | delta) & ~((1 << page_shift) - 1); FAIL_IF(bad_access((char *)addr, false)); FAIL_IF(bad_access((char *)addr, true)); } } return 0; } int main(void) { test_harness_set_timeout(300); return test_harness(test, "bad_accesses"); } |