c1ec1c2aba
This type is primarily used to determine the size of a pointer when using that ABI, similar to the uintptr_t type, but also less directly to determine the "native" size of the ABI. For instance, for 32 bit ARM ABIs, it should be defined as uint32_t since that's both the size of a uintptr_t, and, less directly, the size of a 32 bit ARM register and "naturally" sized types in that ABI. This type can be used by the VPtr template to retrieve its actual value from a simcall's parameters. In general, when accepting or returning a pointer or address in a simcall, the VPtr template should be used so that it's managed correctly by GuestABI. Addr will be treated as a uint64_t allways which will be incorrect for 32 bit ABIs. Change-Id: I3af046917387541d6faff96a21a1f1dbf7317e06 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40496 Maintainer: Gabe Black <gabe.black@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
134 lines
4.2 KiB
C++
134 lines
4.2 KiB
C++
/*
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* Copyright 2019 Google, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __SIM_SYSCALL_ABI_HH__
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#define __SIM_SYSCALL_ABI_HH__
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#include "base/bitfield.hh"
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#include "base/types.hh"
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#include "cpu/thread_context.hh"
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#include "sim/guest_abi.hh"
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#include "sim/syscall_return.hh"
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class SyscallDesc;
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namespace GuestABI
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{
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// Does this normally 64 bit data type shrink down to 32 bits for 32 bit ABIs?
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template <typename T, typename Enabled=void>
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struct IsConforming : public std::false_type {};
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template <>
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struct IsConforming<Addr> : public std::true_type {};
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} // namespace GuestABI
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struct GenericSyscallABI
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{
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using State = int;
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};
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struct GenericSyscallABI64 : public GenericSyscallABI
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{
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using UintPtr = uint64_t;
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};
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struct GenericSyscallABI32 : public GenericSyscallABI
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{
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using UintPtr = uint32_t;
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// Is this argument too big for a single register?
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template <typename T, typename Enabled=void>
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struct IsWide;
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template <typename T>
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struct IsWide<T, typename std::enable_if_t<
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std::is_integral<T>::value &&
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(sizeof(T) <= sizeof(UintPtr) ||
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GuestABI::IsConforming<T>::value)>>
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{
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static const bool value = false;
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};
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template <typename T>
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struct IsWide<T, typename std::enable_if_t<
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std::is_integral<T>::value &&
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(sizeof(T) > sizeof(UintPtr)) &&
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!GuestABI::IsConforming<T>::value>>
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{
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static const bool value = true;
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};
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// Read two registers and merge them into one value.
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static uint64_t
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mergeRegs(ThreadContext *tc, RegIndex low_idx, RegIndex high_idx)
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{
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RegVal low = tc->readIntReg(low_idx);
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RegVal high = tc->readIntReg(high_idx);
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return insertBits(low, 63, 32, high);
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}
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};
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namespace GuestABI
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{
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// For 64 bit systems, return syscall args directly.
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template <typename ABI, typename Arg>
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struct Argument<ABI, Arg,
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typename std::enable_if_t<
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std::is_base_of<GenericSyscallABI64, ABI>::value &&
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std::is_integral<Arg>::value>>
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{
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static Arg
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get(ThreadContext *tc, typename ABI::State &state)
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{
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panic_if(state >= ABI::ArgumentRegs.size(),
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"Ran out of syscall argument registers.");
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return tc->readIntReg(ABI::ArgumentRegs[state++]);
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}
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};
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// For 32 bit systems, return small enough syscall args directly. Large
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// arguments aren't handled generically.
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template <typename ABI, typename Arg>
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struct Argument<ABI, Arg,
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typename std::enable_if_t<!ABI::template IsWide<Arg>::value>>
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{
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static Arg
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get(ThreadContext *tc, typename ABI::State &state)
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{
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panic_if(state >= ABI::ArgumentRegs.size(),
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"Ran out of syscall argument registers.");
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return bits(tc->readIntReg(ABI::ArgumentRegs[state++]), 31, 0);
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}
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};
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} // namespace GuestABI
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#endif // __SIM_SYSCALL_ABI_HH__
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