// SPDX-License-Identifier: GPL-2.0
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/hw_breakpoint.h>
#include <linux/kernel.h>
#include "tests.h"
#include "debug.h"
#include "event.h"
#include "cloexec.h"
#include "../perf-sys.h"

#define WP_TEST_ASSERT_VAL(fd, text, val)       \
do {                                            \
        long long count;                        \
        wp_read(fd, &count, sizeof(long long)); \
        TEST_ASSERT_VAL(text, count == val);    \
} while (0)

volatile u64 data1;
volatile u8 data2[3];

static int wp_read(int fd, long long *count, int size)
{
        int ret = read(fd, count, size);

        if (ret != size) {
                pr_debug("failed to read: %d\n", ret);
                return -1;
        }
        return 0;
}

static void get__perf_event_attr(struct perf_event_attr *attr, int wp_type,
                                 void *wp_addr, unsigned long wp_len)
{
        memset(attr, 0, sizeof(struct perf_event_attr));
        attr->type           = PERF_TYPE_BREAKPOINT;
        attr->size           = sizeof(struct perf_event_attr);
        attr->config         = 0;
        attr->bp_type        = wp_type;
        attr->bp_addr        = (unsigned long)wp_addr;
        attr->bp_len         = wp_len;
        attr->sample_period  = 1;
        attr->sample_type    = PERF_SAMPLE_IP;
        attr->exclude_kernel = 1;
        attr->exclude_hv     = 1;
}

static int __event(int wp_type, void *wp_addr, unsigned long wp_len)
{
        int fd;
        struct perf_event_attr attr;

        get__perf_event_attr(&attr, wp_type, wp_addr, wp_len);
        fd = sys_perf_event_open(&attr, 0, -1, -1,
                                 perf_event_open_cloexec_flag());
        if (fd < 0)
                pr_debug("failed opening event %x\n", attr.bp_type);

        return fd;
}

static int wp_ro_test(void)
{
        int fd;
        unsigned long tmp, tmp1 = rand();

        fd = __event(HW_BREAKPOINT_R, (void *)&data1, sizeof(data1));
        if (fd < 0)
                return -1;

        tmp = data1;
        WP_TEST_ASSERT_VAL(fd, "RO watchpoint", 1);

        data1 = tmp1 + tmp;
        WP_TEST_ASSERT_VAL(fd, "RO watchpoint", 1);

        close(fd);
        return 0;
}

static int wp_wo_test(void)
{
        int fd;
        unsigned long tmp, tmp1 = rand();

        fd = __event(HW_BREAKPOINT_W, (void *)&data1, sizeof(data1));
        if (fd < 0)
                return -1;

        tmp = data1;
        WP_TEST_ASSERT_VAL(fd, "WO watchpoint", 0);

        data1 = tmp1 + tmp;
        WP_TEST_ASSERT_VAL(fd, "WO watchpoint", 1);

        close(fd);
        return 0;
}

static int wp_rw_test(void)
{
        int fd;
        unsigned long tmp, tmp1 = rand();

        fd = __event(HW_BREAKPOINT_R | HW_BREAKPOINT_W, (void *)&data1,
                     sizeof(data1));
        if (fd < 0)
                return -1;

        tmp = data1;
        WP_TEST_ASSERT_VAL(fd, "RW watchpoint", 1);

        data1 = tmp1 + tmp;
        WP_TEST_ASSERT_VAL(fd, "RW watchpoint", 2);

        close(fd);
        return 0;
}

static int wp_modify_test(void)
{
        int fd, ret;
        unsigned long tmp = rand();
        struct perf_event_attr new_attr;

        fd = __event(HW_BREAKPOINT_W, (void *)&data1, sizeof(data1));
        if (fd < 0)
                return -1;

        data1 = tmp;
        WP_TEST_ASSERT_VAL(fd, "Modify watchpoint", 1);

        /* Modify watchpoint with disabled = 1 */
        get__perf_event_attr(&new_attr, HW_BREAKPOINT_W, (void *)&data2[0],
                             sizeof(u8) * 2);
        new_attr.disabled = 1;
        ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &new_attr);
        if (ret < 0) {
                pr_debug("ioctl(PERF_EVENT_IOC_MODIFY_ATTRIBUTES) failed\n");
                close(fd);
                return ret;
        }

        data2[1] = tmp; /* Not Counted */
        WP_TEST_ASSERT_VAL(fd, "Modify watchpoint", 1);

        /* Enable the event */
        ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);
        if (ret < 0) {
                pr_debug("Failed to enable event\n");
                close(fd);
                return ret;
        }

        data2[1] = tmp; /* Counted */
        WP_TEST_ASSERT_VAL(fd, "Modify watchpoint", 2);

        data2[2] = tmp; /* Not Counted */
        WP_TEST_ASSERT_VAL(fd, "Modify watchpoint", 2);

        close(fd);
        return 0;
}

static bool wp_ro_supported(void)
{
#if defined (__x86_64__) || defined (__i386__)
        return false;
#else
        return true;
#endif
}

static const char *wp_ro_skip_msg(void)
{
#if defined (__x86_64__) || defined (__i386__)
        return "missing hardware support";
#else
        return NULL;
#endif
}

static struct {
        const char *desc;
        int (*target_func)(void);
        bool (*is_supported)(void);
        const char *(*skip_msg)(void);
} wp_testcase_table[] = {
        {
                .desc = "Read Only Watchpoint",
                .target_func = &wp_ro_test,
                .is_supported = &wp_ro_supported,
                .skip_msg = &wp_ro_skip_msg,
        },
        {
                .desc = "Write Only Watchpoint",
                .target_func = &wp_wo_test,
        },
        {
                .desc = "Read / Write Watchpoint",
                .target_func = &wp_rw_test,
        },
        {
                .desc = "Modify Watchpoint",
                .target_func = &wp_modify_test,
        },
};

int test__wp_subtest_get_nr(void)
{
        return (int)ARRAY_SIZE(wp_testcase_table);
}

const char *test__wp_subtest_get_desc(int i)
{
        if (i < 0 || i >= (int)ARRAY_SIZE(wp_testcase_table))
                return NULL;
        return wp_testcase_table[i].desc;
}

const char *test__wp_subtest_skip_reason(int i)
{
        if (i < 0 || i >= (int)ARRAY_SIZE(wp_testcase_table))
                return NULL;
        if (!wp_testcase_table[i].skip_msg)
                return NULL;
        return wp_testcase_table[i].skip_msg();
}

int test__wp(struct test *test __maybe_unused, int i)
{
        if (i < 0 || i >= (int)ARRAY_SIZE(wp_testcase_table))
                return TEST_FAIL;

        if (wp_testcase_table[i].is_supported &&
            !wp_testcase_table[i].is_supported())
                return TEST_SKIP;

        return !wp_testcase_table[i].target_func() ? TEST_OK : TEST_FAIL;
}

/* The s390 so far does not have support for
 * instruction breakpoint using the perf_event_open() system call.
 */
bool test__wp_is_supported(void)
{
#if defined(__s390x__)
        return false;
#else
        return true;
#endif
}