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/*
* Copyright 2019 Google, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __SIM_SYSCALL_ABI_HH__
#define __SIM_SYSCALL_ABI_HH__
#include "base/bitfield.hh"
#include "base/types.hh"
#include "cpu/thread_context.hh"
#include "sim/guest_abi.hh"
#include "sim/syscall_return.hh"
class SyscallDesc;
struct GenericSyscallABI
{
using State = int;
};
struct GenericSyscallABI64 : public GenericSyscallABI
{
using UintPtr = uint64_t;
};
struct GenericSyscallABI32 : public GenericSyscallABI
{
using UintPtr = uint32_t;
// Is this argument too big for a single register?
template <typename T, typename Enabled=void>
struct IsWide : public std::false_type {};
template <typename T>
struct IsWide<T, std::enable_if_t<(sizeof(T) > sizeof(UintPtr))>> :
public std::true_type
{};
// Read two registers and merge them into one value.
static uint64_t
mergeRegs(ThreadContext *tc, RegIndex low_idx, RegIndex high_idx)
{
RegVal low = tc->readIntReg(low_idx);
RegVal high = tc->readIntReg(high_idx);
return insertBits(low, 63, 32, high);
}
};
namespace GuestABI
{
// For 64 bit systems, return syscall args directly.
template <typename ABI, typename Arg>
struct Argument<ABI, Arg,
typename std::enable_if_t<
std::is_base_of<GenericSyscallABI64, ABI>::value &&
std::is_integral<Arg>::value>>
{
static Arg
get(ThreadContext *tc, typename ABI::State &state)
{
panic_if(state >= ABI::ArgumentRegs.size(),
"Ran out of syscall argument registers.");
return tc->readIntReg(ABI::ArgumentRegs[state++]);
}
};
// For 32 bit systems, return small enough syscall args directly. Large
// arguments aren't handled generically.
template <typename ABI, typename Arg>
struct Argument<ABI, Arg,
typename std::enable_if_t<std::is_integral<Arg>::value &&
!ABI::template IsWide<Arg>::value>>
{
static Arg
get(ThreadContext *tc, typename ABI::State &state)
{
panic_if(state >= ABI::ArgumentRegs.size(),
"Ran out of syscall argument registers.");
return bits(tc->readIntReg(ABI::ArgumentRegs[state++]), 31, 0);
}
};
} // namespace GuestABI
#endif // __SIM_SYSCALL_ABI_HH__