// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2016 Google, Inc.
 *
 * 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 <asm/ptrace.h>
#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) {
                ksft_print_msg(
                        "ptrace(PTRACE_TRACEME) failed: %s\n",
                        strerror(errno));
                _exit(1);
        }

        if (raise(SIGSTOP) != 0) {
                ksft_print_msg(
                        "raise(SIGSTOP) failed: %s\n", strerror(errno));
                _exit(1);
        }

        if ((uintptr_t) addr % size) {
                ksft_print_msg(
                         "Wrong address write for the given size: %s\n",
                         strerror(errno));
                _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)
                ksft_print_msg(
                        "ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) not supported on this hardware: %s\n",
                        strerror(errno));

        ksft_print_msg(
                "ptrace(PTRACE_SETREGSET, NT_ARM_HW_WATCH) failed: %s\n",
                strerror(errno));
        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) {
                ksft_test_result_fail(
                        "fork() failed: %s\n", strerror(errno));
                return false;
        }
        if (pid == 0)
                child(wr_size, wr);

        wpid = waitpid(pid, &status, __WALL);
        if (wpid != pid) {
                ksft_print_msg(
                        "waitpid() failed: %s\n", strerror(errno));
                return false;
        }
        if (!WIFSTOPPED(status)) {
                ksft_print_msg(
                        "child did not stop: %s\n", strerror(errno));
                return false;
        }
        if (WSTOPSIG(status) != SIGSTOP) {
                ksft_print_msg("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) {
                ksft_print_msg(
                        "ptrace(PTRACE_CONT) failed: %s\n",
                        strerror(errno));
                return false;
        }

        alarm(3);
        wpid = waitpid(pid, &status, __WALL);
        if (wpid != pid) {
                ksft_print_msg(
                        "waitpid() failed: %s\n", strerror(errno));
                return false;
        }
        alarm(0);
        if (WIFEXITED(status)) {
                ksft_print_msg("child exited prematurely\n");
                return false;
        }
        if (!WIFSTOPPED(status)) {
                ksft_print_msg("child did not stop\n");
                return false;
        }
        if (WSTOPSIG(status) != SIGTRAP) {
                ksft_print_msg("child did not stop with SIGTRAP\n");
                return false;
        }
        if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo) != 0) {
                ksft_print_msg(
                        "ptrace(PTRACE_GETSIGINFO): %s\n",
                        strerror(errno));
                return false;
        }
        if (siginfo.si_code != TRAP_HWBKPT) {
                ksft_print_msg(
                        "Unexpected si_code %d\n", siginfo.si_code);
                return false;
        }

        kill(pid, SIGKILL);
        wpid = waitpid(pid, &status, 0);
        if (wpid != pid) {
                ksft_print_msg(
                        "waitpid() failed: %s\n", strerror(errno));
                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;

        ksft_print_header();
        ksft_set_plan(213);

        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) {
                                result = run_test(size, MIN(size, 8), wr, wp);
                                if ((result && wr == wp) ||
                                    (!result && wr != wp))
                                        ksft_test_result_pass(
                                                "Test size = %d write offset = %d watchpoint offset = %d\n",
                                                size, wr, wp);
                                else {
                                        ksft_test_result_fail(
                                                "Test size = %d write offset = %d watchpoint offset = %d\n",
                                                size, wr, wp);
                                        succeeded = false;
                                }
                        }
                }
        }

        for (size = 1; size <= 32; size = size*2) {
                if (run_test(size, 8, -size, -8))
                        ksft_test_result_pass(
                                "Test size = %d write offset = %d watchpoint offset = -8\n",
                                size, -size);
                else {
                        ksft_test_result_fail(
                                "Test size = %d write offset = %d watchpoint offset = -8\n",
                                size, -size);
                        succeeded = false;
                }
        }

        if (succeeded)
                ksft_exit_pass();
        else
                ksft_exit_fail();
}