include/gdbstub/helpers.h

/*
 * gdbstub helpers
 *
 * These are all used by the various frontends and have to be host
 * aware to ensure things are store in target order.
 *
 * Copyright (c) 2022 Linaro Ltd
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#ifndef _GDBSTUB_HELPERS_H_
#define _GDBSTUB_HELPERS_H_

#ifndef COMPILING_PER_TARGET
#error "gdbstub helpers should only be included by target specific code"
#endif

#include "exec/tswap.h"
#include "cpu-param.h"

/*
 * The GDB remote protocol transfers values in target byte order. As
 * the gdbstub may be batching up several register values we always
 * append to the array.
 */

static inline int gdb_get_reg8(GByteArray *buf, uint8_t val)
{
    g_byte_array_append(buf, &val, 1);
    return 1;
}

static inline int gdb_get_reg16(GByteArray *buf, uint16_t val)
{
    uint16_t to_word = tswap16(val);
    g_byte_array_append(buf, (uint8_t *) &to_word, 2);
    return 2;
}

static inline int gdb_get_reg32(GByteArray *buf, uint32_t val)
{
    uint32_t to_long = tswap32(val);
    g_byte_array_append(buf, (uint8_t *) &to_long, 4);
    return 4;
}

static inline int gdb_get_reg64(GByteArray *buf, uint64_t val)
{
    uint64_t to_quad = tswap64(val);
    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
    return 8;
}

static inline int gdb_get_reg128(GByteArray *buf, uint64_t val_hi,
                                 uint64_t val_lo)
{
    uint64_t to_quad;
#if TARGET_BIG_ENDIAN
    to_quad = tswap64(val_hi);
    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
    to_quad = tswap64(val_lo);
    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
#else
    to_quad = tswap64(val_lo);
    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
    to_quad = tswap64(val_hi);
    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
#endif
    return 16;
}

static inline int gdb_get_zeroes(GByteArray *array, size_t len)
{
    guint oldlen = array->len;
    g_byte_array_set_size(array, oldlen + len);
    memset(array->data + oldlen, 0, len);

    return len;
}

/**
 * gdb_get_reg_ptr: get pointer to start of last element
 * @len: length of element
 *
 * This is a helper function to extract the pointer to the last
 * element for additional processing. Some front-ends do additional
 * dynamic swapping of the elements based on CPU state.
 */
static inline uint8_t *gdb_get_reg_ptr(GByteArray *buf, int len)
{
    return buf->data + buf->len - len;
}

#if TARGET_LONG_BITS == 64
#define gdb_get_regl(buf, val) gdb_get_reg64(buf, val)
#define ldtul_p(addr) ldq_p(addr)
#define ldtul_le_p(addr) ldq_le_p(addr)
#define ldtul_be_p(addr) ldq_be_p(addr)
#else
#define gdb_get_regl(buf, val) gdb_get_reg32(buf, val)
#define ldtul_p(addr) ldl_p(addr)
#define ldtul_le_p(addr) ldl_le_p(addr)
#define ldtul_be_p(addr) ldl_be_p(addr)
#endif

#endif /* _GDBSTUB_HELPERS_H_ */