/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __TRACE_PROBE_KERNEL_H_
#define __TRACE_PROBE_KERNEL_H_

/*
 * This depends on trace_probe.h, but can not include it due to
 * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
 * Which means that any other user must include trace_probe.h before including
 * this file.
 */
/* Return the length of string -- including null terminal byte */
static nokprobe_inline int
fetch_store_strlen_user(unsigned long addr)
{
        const void __user *uaddr =  (__force const void __user *)addr;

        return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
}

/* Return the length of string -- including null terminal byte */
static nokprobe_inline int
fetch_store_strlen(unsigned long addr)
{
        int ret, len = 0;
        u8 c;

#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
        if (addr < TASK_SIZE)
                return fetch_store_strlen_user(addr);
#endif

        do {
                ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
                len++;
        } while (c && ret == 0 && len < MAX_STRING_SIZE);

        return (ret < 0) ? ret : len;
}

static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base)
{
        if (ret < 0)
                ret = 0;
        *(u32 *)dest = make_data_loc(ret, __dest - base);
}

/*
 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
 * with max length and relative data location.
 */
static nokprobe_inline int
fetch_store_string_user(unsigned long addr, void *dest, void *base)
{
        const void __user *uaddr =  (__force const void __user *)addr;
        int maxlen = get_loc_len(*(u32 *)dest);
        void *__dest;
        long ret;

        if (unlikely(!maxlen))
                return -ENOMEM;

        __dest = get_loc_data(dest, base);

        ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
        set_data_loc(ret, dest, __dest, base);

        return ret;
}

/*
 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
 * length and relative data location.
 */
static nokprobe_inline int
fetch_store_string(unsigned long addr, void *dest, void *base)
{
        int maxlen = get_loc_len(*(u32 *)dest);
        void *__dest;
        long ret;

#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
        if ((unsigned long)addr < TASK_SIZE)
                return fetch_store_string_user(addr, dest, base);
#endif

        if (unlikely(!maxlen))
                return -ENOMEM;

        __dest = get_loc_data(dest, base);

        /*
         * Try to get string again, since the string can be changed while
         * probing.
         */
        ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
        set_data_loc(ret, dest, __dest, base);

        return ret;
}

static nokprobe_inline int
probe_mem_read_user(void *dest, void *src, size_t size)
{
        const void __user *uaddr =  (__force const void __user *)src;

        return copy_from_user_nofault(dest, uaddr, size);
}

static nokprobe_inline int
probe_mem_read(void *dest, void *src, size_t size)
{
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
        if ((unsigned long)src < TASK_SIZE)
                return probe_mem_read_user(dest, src, size);
#endif
        return copy_from_kernel_nofault(dest, src, size);
}

#endif /* __TRACE_PROBE_KERNEL_H_ */