// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <syscall.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
#include <asm/ptrace.h>
#include <errno.h>
#include "debug.h"
#include "tests/tests.h"
#include "arch-tests.h"

static noinline int bp_1(void)
{
        pr_debug("in %s\n", __func__);
        return 0;
}

static noinline int bp_2(void)
{
        pr_debug("in %s\n", __func__);
        return 0;
}

static int spawn_child(void)
{
        int child = fork();

        if (child == 0) {
                /*
                 * The child sets itself for as tracee and
                 * waits in signal for parent to trace it,
                 * then it calls bp_1 and quits.
                 */
                int err = ptrace(PTRACE_TRACEME, 0, NULL, NULL);

                if (err) {
                        pr_debug("failed to PTRACE_TRACEME\n");
                        exit(1);
                }

                raise(SIGCONT);
                bp_1();
                exit(0);
        }

        return child;
}

/*
 * This tests creates HW breakpoint, tries to
 * change it and checks it was properly changed.
 */
static int bp_modify1(void)
{
        pid_t child;
        int status;
        unsigned long rip = 0, dr7 = 1;

        child = spawn_child();

        waitpid(child, &status, 0);
        if (WIFEXITED(status)) {
                pr_debug("tracee exited prematurely 1\n");
                return TEST_FAIL;
        }

        /*
         * The parent does following steps:
         *  - creates a new breakpoint (id 0) for bp_2 function
         *  - changes that breakpoint to bp_1 function
         *  - waits for the breakpoint to hit and checks
         *    it has proper rip of bp_1 function
         *  - detaches the child
         */
        if (ptrace(PTRACE_POKEUSER, child,
                   offsetof(struct user, u_debugreg[0]), bp_2)) {
                pr_debug("failed to set breakpoint, 1st time: %s\n",
                         strerror(errno));
                goto out;
        }

        if (ptrace(PTRACE_POKEUSER, child,
                   offsetof(struct user, u_debugreg[0]), bp_1)) {
                pr_debug("failed to set breakpoint, 2nd time: %s\n",
                         strerror(errno));
                goto out;
        }

        if (ptrace(PTRACE_POKEUSER, child,
                   offsetof(struct user, u_debugreg[7]), dr7)) {
                pr_debug("failed to set dr7: %s\n", strerror(errno));
                goto out;
        }

        if (ptrace(PTRACE_CONT, child, NULL, NULL)) {
                pr_debug("failed to PTRACE_CONT: %s\n", strerror(errno));
                goto out;
        }

        waitpid(child, &status, 0);
        if (WIFEXITED(status)) {
                pr_debug("tracee exited prematurely 2\n");
                return TEST_FAIL;
        }

        rip = ptrace(PTRACE_PEEKUSER, child,
                     offsetof(struct user_regs_struct, rip), NULL);
        if (rip == (unsigned long) -1) {
                pr_debug("failed to PTRACE_PEEKUSER: %s\n",
                         strerror(errno));
                goto out;
        }

        pr_debug("rip %lx, bp_1 %p\n", rip, bp_1);

out:
        if (ptrace(PTRACE_DETACH, child, NULL, NULL)) {
                pr_debug("failed to PTRACE_DETACH: %s", strerror(errno));
                return TEST_FAIL;
        }

        return rip == (unsigned long) bp_1 ? TEST_OK : TEST_FAIL;
}

/*
 * This tests creates HW breakpoint, tries to
 * change it to bogus value and checks the original
 * breakpoint is hit.
 */
static int bp_modify2(void)
{
        pid_t child;
        int status;
        unsigned long rip = 0, dr7 = 1;

        child = spawn_child();

        waitpid(child, &status, 0);
        if (WIFEXITED(status)) {
                pr_debug("tracee exited prematurely 1\n");
                return TEST_FAIL;
        }

        /*
         * The parent does following steps:
         *  - creates a new breakpoint (id 0) for bp_1 function
         *  - tries to change that breakpoint to (-1) address
         *  - waits for the breakpoint to hit and checks
         *    it has proper rip of bp_1 function
         *  - detaches the child
         */
        if (ptrace(PTRACE_POKEUSER, child,
                   offsetof(struct user, u_debugreg[0]), bp_1)) {
                pr_debug("failed to set breakpoint: %s\n",
                         strerror(errno));
                goto out;
        }

        if (ptrace(PTRACE_POKEUSER, child,
                   offsetof(struct user, u_debugreg[7]), dr7)) {
                pr_debug("failed to set dr7: %s\n", strerror(errno));
                goto out;
        }

        if (!ptrace(PTRACE_POKEUSER, child,
                   offsetof(struct user, u_debugreg[0]), (unsigned long) (-1))) {
                pr_debug("failed, breakpoint set to bogus address\n");
                goto out;
        }

        if (ptrace(PTRACE_CONT, child, NULL, NULL)) {
                pr_debug("failed to PTRACE_CONT: %s\n", strerror(errno));
                goto out;
        }

        waitpid(child, &status, 0);
        if (WIFEXITED(status)) {
                pr_debug("tracee exited prematurely 2\n");
                return TEST_FAIL;
        }

        rip = ptrace(PTRACE_PEEKUSER, child,
                     offsetof(struct user_regs_struct, rip), NULL);
        if (rip == (unsigned long) -1) {
                pr_debug("failed to PTRACE_PEEKUSER: %s\n",
                         strerror(errno));
                goto out;
        }

        pr_debug("rip %lx, bp_1 %p\n", rip, bp_1);

out:
        if (ptrace(PTRACE_DETACH, child, NULL, NULL)) {
                pr_debug("failed to PTRACE_DETACH: %s", strerror(errno));
                return TEST_FAIL;
        }

        return rip == (unsigned long) bp_1 ? TEST_OK : TEST_FAIL;
}

int test__bp_modify(struct test *test __maybe_unused,
                    int subtest __maybe_unused)
{
        TEST_ASSERT_VAL("modify test 1 failed\n", !bp_modify1());
        TEST_ASSERT_VAL("modify test 2 failed\n", !bp_modify2());

        return 0;
}