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Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/powerpc/mm/bad_accesses.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/mm/bad_accesses.c b/tools/testing/selftests/powerpc/mm/bad_accesses.c new file mode 100644 index 000000000..fd747b2ff --- /dev/null +++ b/tools/testing/selftests/powerpc/mm/bad_accesses.c @@ -0,0 +1,144 @@ +// 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"); +} |