x86/StackFrame.cc

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "pedigree/kernel/processor/StackFrame.h"
#include "pedigree/kernel/Log.h"
#include <stdarg.h>

#ifdef DEBUGGER
uintptr_t X86StackFrame::getParameter(size_t n)
{
    if (m_BasePointer < 0x2000)
        return 0;
#if defined(OMIT_FRAMEPOINTER)
    uint32_t *pPtr = reinterpret_cast<uint32_t *>(
        m_BasePointer + (n + 1) * sizeof(uint32_t));
#else
    uint32_t *pPtr = reinterpret_cast<uint32_t *>(
        m_BasePointer + (n + 2) * sizeof(uint32_t));
#endif
    return *pPtr;
}
#endif

void X86StackFrame::construct(
    ProcessorState &state, uintptr_t returnAddress, unsigned int nParams, ...)
{
    // Obtain the stack pointer.
    uintptr_t *pStack = reinterpret_cast<uintptr_t *>(state.getStackPointer());

    // How many parameters do we need to push?
    // We push in reverse order but must iterate through the va_list in forward
    // order, so we decrement the stack pointer here.
    pStack -= nParams + 1;  // +1 for return address.
    uintptr_t *pStackLowWaterMark = pStack;

    *pStack++ = returnAddress;

    va_list list;
    va_start(list, nParams);

    for (int i = nParams - 1; i >= 0; i--)
    {
        *pStack++ = va_arg(list, uintptr_t);
    }

    va_end(list);

    // Write the new stack pointer back.
    state.setStackPointer(reinterpret_cast<uintptr_t>(pStackLowWaterMark));
}