Commit f43365ee authored by Pratyush Anand's avatar Pratyush Anand Committed by Will Deacon
Browse files

selftests: arm64: add test for unaligned/inexact watchpoint handling 



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: default avatarPavel Labath <labath@google.com>
Signed-off-by: default avatarPratyush Anand <panand@redhat.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 0ddb8e0b

tools/testing/selftests/breakpoints/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/breakpoints/breakpoint_test_arm64.c

0 → 100644
+236 −0
Original line number Diff line number Diff line 
/*

 * 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();

}

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