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-rw-r--r--tools/testing/selftests/powerpc/mm/bad_accesses.c171
1 files changed, 171 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 000000000000..adc465f499ef
--- /dev/null
+++ b/tools/testing/selftests/powerpc/mm/bad_accesses.c
@@ -0,0 +1,171 @@
+// 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 using_hash_mmu(bool *using_hash)
+{
+ char line[128];
+ FILE *f;
+ int rc;
+
+ f = fopen("/proc/cpuinfo", "r");
+ FAIL_IF(!f);
+
+ rc = 0;
+ while (fgets(line, sizeof(line), f) != NULL) {
+ if (strcmp(line, "MMU : Hash\n") == 0) {
+ *using_hash = true;
+ goto out;
+ }
+
+ if (strcmp(line, "MMU : Radix\n") == 0) {
+ *using_hash = false;
+ goto out;
+ }
+ }
+
+ rc = -1;
+out:
+ fclose(f);
+ return rc;
+}
+
+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)
+{
+ return test_harness(test, "bad_accesses");
+}