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Subject[PATCH V3 5/5] selftests: arm64: add test for unaligned/inexact watchpoint handling
Date
ARM64 hardware expects 64bit aligned address for watchpoint invocation.
However, it provides byte selection method to select any number of
consecutive byte set within the range of 1-8.

This patch adds support to test all such byte selection option for
different memory write sizes.

Patch also adds a test for handling the case when the cpu does not
report an address which exactly matches one of the regions we have
been watching (which is a situation permitted by the spec if an
instruction accesses both watched and unwatched regions). The test
was failing on a MSM8996pro before this patch series and is
passing now.

Signed-off-by: Pavel Labath <labath@google.com>
Signed-off-by: Pratyush Anand <panand@redhat.com>
---
tools/testing/selftests/breakpoints/Makefile | 5 +-
.../selftests/breakpoints/breakpoint_test_arm64.c | 236 +++++++++++++++++++++
2 files changed, 240 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/breakpoints/breakpoint_test_arm64.c

diff --git a/tools/testing/selftests/breakpoints/Makefile b/tools/testing/selftests/breakpoints/Makefile
index 74e533fd4bc5..61b79e8df1f4 100644
--- a/tools/testing/selftests/breakpoints/Makefile
+++ b/tools/testing/selftests/breakpoints/Makefile
@@ -5,6 +5,9 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
ifeq ($(ARCH),x86)
TEST_PROGS := breakpoint_test
endif
+ifeq ($(ARCH),aarch64)
+TEST_PROGS := breakpoint_test_arm64
+endif

TEST_PROGS += step_after_suspend_test

@@ -13,4 +16,4 @@ all: $(TEST_PROGS)
include ../lib.mk

clean:
- rm -fr breakpoint_test step_after_suspend_test
+ rm -fr breakpoint_test breakpoint_test_arm64 step_after_suspend_test
diff --git a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
new file mode 100644
index 000000000000..3897e996541e
--- /dev/null
+++ b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
@@ -0,0 +1,236 @@
+/*
+ * Copyright (C) 2016 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Original Code by Pavel Labath <labath@google.com>
+ *
+ * Code modified by Pratyush Anand <panand@redhat.com>
+ * for testing different byte select for each access size.
+ *
+ */
+
+#define _GNU_SOURCE
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/ptrace.h>
+#include <sys/param.h>
+#include <sys/uio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <elf.h>
+#include <errno.h>
+#include <signal.h>
+
+#include "../kselftest.h"
+
+static volatile uint8_t var[96] __attribute__((__aligned__(32)));
+
+static void child(int size, int wr)
+{
+ volatile uint8_t *addr = &var[32 + wr];
+
+ if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) != 0) {
+ perror("ptrace(PTRACE_TRACEME) failed");
+ _exit(1);
+ }
+
+ if (raise(SIGSTOP) != 0) {
+ perror("raise(SIGSTOP) failed");
+ _exit(1);
+ }
+
+ if ((uintptr_t) addr % size) {
+ perror("Wrong address write for the given size\n");
+ _exit(1);
+ }
+ switch (size) {
+ case 1:
+ *addr = 47;
+ break;
+ case 2:
+ *(uint16_t *)addr = 47;
+ break;
+ case 4:
+ *(uint32_t *)addr = 47;
+ break;
+ case 8:
+ *(uint64_t *)addr = 47;
+ break;
+ case 16:
+ __asm__ volatile ("stp x29, x30, %0" : "=m" (addr[0]));
+ break;
+ case 32:
+ __asm__ volatile ("stp q29, q30, %0" : "=m" (addr[0]));
+ break;
+ }
+
+ _exit(0);
+}
+
+static bool set_watchpoint(pid_t pid, int size, int wp)
+{
+ const volatile uint8_t *addr = &var[32 + wp];
+ const int offset = (uintptr_t)addr % 8;
+ const unsigned int byte_mask = ((1 << size) - 1) << offset;
+ const unsigned int type = 2; /* Write */
+ const unsigned int enable = 1;
+ const unsigned int control = byte_mask << 5 | type << 3 | enable;
+ struct user_hwdebug_state dreg_state;
+ struct iovec iov;
+
+ memset(&dreg_state, 0, sizeof(dreg_state));
+ dreg_state.dbg_regs[0].addr = (uintptr_t)(addr - offset);
+ dreg_state.dbg_regs[0].ctrl = control;
+ iov.iov_base = &dreg_state;
+ iov.iov_len = offsetof(struct user_hwdebug_state, dbg_regs) +
+ sizeof(dreg_state.dbg_regs[0]);
+ if (ptrace(PTRACE_SETREGSET, pid, NT_ARM_HW_WATCH, &iov) == 0)
+ return true;
+
+ if (errno == EIO) {
+ printf("ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) "
+ "not supported on this hardware\n");
+ ksft_exit_skip();
+ }
+ perror("ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) failed");
+ return false;
+}
+
+static bool run_test(int wr_size, int wp_size, int wr, int wp)
+{
+ int status;
+ siginfo_t siginfo;
+ pid_t pid = fork();
+ pid_t wpid;
+
+ if (pid < 0) {
+ perror("fork() failed");
+ return false;
+ }
+ if (pid == 0)
+ child(wr_size, wr);
+
+ wpid = waitpid(pid, &status, __WALL);
+ if (wpid != pid) {
+ perror("waitpid() failed");
+ return false;
+ }
+ if (!WIFSTOPPED(status)) {
+ printf("child did not stop\n");
+ return false;
+ }
+ if (WSTOPSIG(status) != SIGSTOP) {
+ printf("child did not stop with SIGSTOP\n");
+ return false;
+ }
+
+ if (!set_watchpoint(pid, wp_size, wp))
+ return false;
+
+ if (ptrace(PTRACE_CONT, pid, NULL, NULL) < 0) {
+ perror("ptrace(PTRACE_SINGLESTEP) failed");
+ return false;
+ }
+
+ alarm(3);
+ wpid = waitpid(pid, &status, __WALL);
+ if (wpid != pid) {
+ perror("waitpid() failed");
+ return false;
+ }
+ alarm(0);
+ if (WIFEXITED(status)) {
+ printf("child did not single-step\t");
+ return false;
+ }
+ if (!WIFSTOPPED(status)) {
+ printf("child did not stop\n");
+ return false;
+ }
+ if (WSTOPSIG(status) != SIGTRAP) {
+ printf("child did not stop with SIGTRAP\n");
+ return false;
+ }
+ if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo) != 0) {
+ perror("ptrace(PTRACE_GETSIGINFO)");
+ return false;
+ }
+ if (siginfo.si_code != TRAP_HWBKPT) {
+ printf("Unexpected si_code %d\n", siginfo.si_code);
+ return false;
+ }
+
+ kill(pid, SIGKILL);
+ wpid = waitpid(pid, &status, 0);
+ if (wpid != pid) {
+ perror("waitpid() failed");
+ return false;
+ }
+ return true;
+}
+
+static void sigalrm(int sig)
+{
+}
+
+int main(int argc, char **argv)
+{
+ int opt;
+ bool succeeded = true;
+ struct sigaction act;
+ int wr, wp, size;
+ bool result;
+
+ act.sa_handler = sigalrm;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ sigaction(SIGALRM, &act, NULL);
+ for (size = 1; size <= 32; size = size*2) {
+ for (wr = 0; wr <= 32; wr = wr + size) {
+ for (wp = wr - size; wp <= wr + size; wp = wp + size) {
+ printf("Test size = %d write offset = %d watchpoint offset = %d\t", size, wr, wp);
+ result = run_test(size, MIN(size, 8), wr, wp);
+ if ((result && wr == wp) || (!result && wr != wp)) {
+ printf("[OK]\n");
+ ksft_inc_pass_cnt();
+ } else {
+ printf("[FAILED]\n");
+ ksft_inc_fail_cnt();
+ succeeded = false;
+ }
+ }
+ }
+ }
+
+ for (size = 1; size <= 32; size = size*2) {
+ printf("Test size = %d write offset = %d watchpoint offset = -8\t", size, -size);
+
+ if (run_test(size, 8, -size, -8)) {
+ printf("[OK]\n");
+ ksft_inc_pass_cnt();
+ } else {
+ printf("[FAILED]\n");
+ ksft_inc_fail_cnt();
+ succeeded = false;
+ }
+ }
+
+ ksft_print_cnts();
+ if (succeeded)
+ ksft_exit_pass();
+ else
+ ksft_exit_fail();
+}
--
2.7.4
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