gem5/src/arch/riscv/isa/formats/mem.isa
Alec Roelke 535e6c5fa4 riscv: [Patch 4/5] Added RISC-V atomic memory extension RV64A
Fourth of five patches adding RISC-V to GEM5. This patch adds the RV64A
extension, which includes atomic memory instructions. These instructions
atomically read a value from memory, modify it with a value contained in a
source register, and store the original memory value in the destination
register and modified value back into memory. Because this requires two
memory accesses and GEM5 does not support two timing memory accesses in
a single instruction, each of these instructions is split into two micro-
ops: A "load" micro-op, which reads the memory, and a "store" micro-op,
which modifies and writes it back.  Each atomic memory instruction also has
two bits that acquire and release a lock on its memory location.
Additionally, there are atomic load and store instructions that only either
load or store, but not both, and can acquire or release memory locks.

Note that because the current implementation of RISC-V only supports one
core and one thread, it doesn't make sense to make use of AMO instructions.
However, they do form a standard extension of the RISC-V ISA, so they are
included mostly as a placeholder for when multithreaded execution is
implemented.  As a result, any tests for their correctness in a future
patch may be abbreviated.

Patch 1 introduced RISC-V and implemented the base instruction set, RV64I;
patch 2 implemented the integer multiply extension, RV64M; and patch 3
implemented the single- and double-precision floating point extensions,
RV64FD.

Patch 5 will add support for timing, minor, and detailed CPU models that
isn't present in patches 1-4.

[Added missing file amo.isa]
[Replaced information removed from initial patch that was missed during
division into multiple patches.]
[Fixed some minor formatting issues.]
[Fixed oversight where LR and SC didn't have both AQ and RL flags.]
Signed-off by: Alec Roelke

Signed-off by: Jason Lowe-Power <jason@lowepower.com>
2016-11-30 17:10:28 -05:00

437 lines
11 KiB
C++

// -*- mode:c++ -*-
// Copyright (c) 2015 RISC-V Foundation
// Copyright (c) 2016 The University of Virginia
// All rights reserved.
//
// 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.
//
// Authors: Alec Roelke
////////////////////////////////////////////////////////////////////
//
// Memory operation instructions
//
output header {{
class Load : public RiscvStaticInst
{
public:
/// Displacement for EA calculation (signed).
int64_t ldisp;
protected:
/// Memory request flags. See mem_req_base.hh.
Request::Flags memAccessFlags;
/// Constructor
Load(const char *mnem, ExtMachInst _machInst, OpClass __opClass)
: RiscvStaticInst(mnem, _machInst, __opClass), ldisp(IMM12)
{
if (IMMSIGN > 0)
ldisp |= ~((uint64_t)0xFFF);
}
std::string
generateDisassembly(Addr pc, const SymbolTable *symtab) const;
};
class Store : public RiscvStaticInst
{
public:
/// Displacement for EA calculation (signed).
int64_t sdisp;
protected:
/// Memory request flags. See mem_req_base.hh.
Request::Flags memAccessFlags;
/// Constructor
Store(const char *mnem, ExtMachInst _machInst, OpClass __opClass)
: RiscvStaticInst(mnem, _machInst, __opClass), sdisp(IMM5)
{
sdisp |= IMM7 << 5;
if (IMMSIGN > 0)
sdisp |= ~((uint64_t)0xFFF);
}
std::string
generateDisassembly(Addr pc, const SymbolTable *symtab) const;
};
}};
output decoder {{
std::string
Load::generateDisassembly(Addr pc, const SymbolTable *symtab) const
{
std::stringstream ss;
ss << mnemonic << ' ' << regName(_destRegIdx[0]) << ", " << ldisp <<
'(' << regName(_srcRegIdx[0]) << ')';
return ss.str();
}
std::string
Store::generateDisassembly(Addr pc, const SymbolTable *symtab) const
{
std::stringstream ss;
ss << mnemonic << ' ' << regName(_srcRegIdx[1]) << ", " << sdisp <<
'(' << regName(_srcRegIdx[0]) << ')';
return ss.str();
}
}};
def template LoadStoreDeclare {{
/**
* Static instruction class for "%(mnemonic)s".
*/
class %(class_name)s : public %(base_class)s
{
public:
/// Constructor.
%(class_name)s(ExtMachInst machInst);
%(BasicExecDeclare)s
%(EACompDeclare)s
%(InitiateAccDeclare)s
%(CompleteAccDeclare)s
};
}};
def template EACompDeclare {{
Fault
eaComp(%(CPU_exec_context)s *, Trace::InstRecord *) const;
}};
def template InitiateAccDeclare {{
Fault
initiateAcc(%(CPU_exec_context)s *, Trace::InstRecord *) const;
}};
def template CompleteAccDeclare {{
Fault
completeAcc(PacketPtr, %(CPU_exec_context)s *, Trace::InstRecord *) const;
}};
def template LoadStoreConstructor {{
%(class_name)s::%(class_name)s(ExtMachInst machInst):
%(base_class)s("%(mnemonic)s", machInst, %(op_class)s)
{
%(constructor)s;
}
}};
def template EACompExecute {{
Fault
%(class_name)s::eaComp(CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Addr EA;
Fault fault = NoFault;
%(op_decl)s;
%(op_rd)s;
%(ea_code)s;
if (fault == NoFault) {
%(op_wb)s;
xc->setEA(EA);
}
return fault;
}
}};
let {{
def LoadStoreBase(name, Name, ea_code, memacc_code, mem_flags, inst_flags,
base_class, postacc_code='', decode_template=BasicDecode,
exec_template_base=''):
# Make sure flags are in lists (convert to lists if not).
mem_flags = makeList(mem_flags)
inst_flags = makeList(inst_flags) # + ['IsNonSpeculative']
iop = InstObjParams(name, Name, base_class,
{ 'ea_code':ea_code, 'memacc_code':memacc_code,
'postacc_code':postacc_code }, inst_flags)
if mem_flags:
mem_flags = [ 'Request::%s' % flag for flag in mem_flags ]
s = '\n\tmemAccessFlags = ' + string.join(mem_flags, '|') + ';'
iop.constructor += s
# select templates
# The InitiateAcc template is the same for StoreCond templates as the
# corresponding Store template..
StoreCondInitiateAcc = StoreInitiateAcc
fullExecTemplate = eval(exec_template_base + 'Execute')
initiateAccTemplate = eval(exec_template_base + 'InitiateAcc')
completeAccTemplate = eval(exec_template_base + 'CompleteAcc')
# (header_output, decoder_output, decode_block, exec_output)
return (LoadStoreDeclare.subst(iop),
LoadStoreConstructor.subst(iop),
decode_template.subst(iop),
fullExecTemplate.subst(iop) +
EACompExecute.subst(iop) +
initiateAccTemplate.subst(iop) +
completeAccTemplate.subst(iop))
}};
def template LoadExecute {{
Fault
%(class_name)s::execute(CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Addr EA;
Fault fault = NoFault;
%(op_decl)s;
%(op_rd)s;
%(ea_code)s;
if (fault == NoFault) {
fault = readMemAtomic(xc, traceData, EA, Mem, memAccessFlags);
%(memacc_code)s;
}
if (fault == NoFault) {
%(op_wb)s;
}
return fault;
}
}};
def template LoadInitiateAcc {{
Fault
%(class_name)s::initiateAcc(CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Addr EA;
Fault fault = NoFault;
%(op_src_decl)s;
%(op_rd)s;
%(ea_code)s;
if (fault == NoFault) {
fault = initiateMemRead(xc, traceData, EA, Mem, memAccessFlags);
}
return fault;
}
}};
def template LoadCompleteAcc {{
Fault
%(class_name)s::completeAcc(PacketPtr pkt, CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Fault fault = NoFault;
%(op_decl)s;
%(op_rd)s;
getMem(pkt, Mem, traceData);
if (fault == NoFault) {
%(memacc_code)s;
}
if (fault == NoFault) {
%(op_wb)s;
}
return fault;
}
}};
def template StoreExecute {{
Fault
%(class_name)s::execute(CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Addr EA;
Fault fault = NoFault;
%(op_decl)s;
%(op_rd)s;
%(ea_code)s;
if (fault == NoFault) {
%(memacc_code)s;
}
if (fault == NoFault) {
fault = writeMemAtomic(xc, traceData, Mem, EA, memAccessFlags,
nullptr);
}
if (fault == NoFault) {
%(postacc_code)s;
}
if (fault == NoFault) {
%(op_wb)s;
}
return fault;
}
}};
def template StoreInitiateAcc {{
Fault
%(class_name)s::initiateAcc(CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Addr EA;
Fault fault = NoFault;
%(op_decl)s;
%(op_rd)s;
%(ea_code)s;
if (fault == NoFault) {
%(memacc_code)s;
}
if (fault == NoFault) {
fault = writeMemTiming(xc, traceData, Mem, EA,
memAccessFlags, nullptr);
}
if (fault == NoFault) {
%(op_wb)s;
}
return fault;
}
}};
def template StoreCompleteAcc {{
Fault
%(class_name)s::completeAcc(PacketPtr pkt, CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
return NoFault;
}
}};
def template StoreCondExecute {{
Fault %(class_name)s::execute(CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Addr EA;
Fault fault = NoFault;
uint64_t result;
%(op_decl)s;
%(op_rd)s;
%(ea_code)s;
if (fault == NoFault) {
%(memacc_code)s;
}
if (fault == NoFault) {
fault = writeMemAtomic(xc, traceData, Mem, EA, memAccessFlags,
&result);
}
if (fault == NoFault) {
%(postacc_code)s;
}
if (fault == NoFault) {
%(op_wb)s;
}
return fault;
}
}};
def template StoreCondCompleteAcc {{
Fault %(class_name)s::completeAcc(Packet *pkt, CPU_EXEC_CONTEXT *xc,
Trace::InstRecord *traceData) const
{
Fault fault = NoFault;
%(op_dest_decl)s;
uint64_t result = pkt->req->getExtraData();
if (fault == NoFault) {
%(postacc_code)s;
}
if (fault == NoFault) {
%(op_wb)s;
}
return fault;
}
}};
def format Load(memacc_code, ea_code = {{EA = Rs1 + ldisp;}}, mem_flags=[],
inst_flags=[]) {{
(header_output, decoder_output, decode_block, exec_output) = \
LoadStoreBase(name, Name, ea_code, memacc_code, mem_flags, inst_flags,
'Load', exec_template_base='Load')
}};
def format Store(memacc_code, ea_code={{EA = Rs1 + sdisp;}}, mem_flags=[],
inst_flags=[]) {{
(header_output, decoder_output, decode_block, exec_output) = \
LoadStoreBase(name, Name, ea_code, memacc_code, mem_flags, inst_flags,
'Store', exec_template_base='Store')
}};
def format StoreCond(memacc_code, postacc_code, ea_code={{EA = Rs1;}},
mem_flags=[], inst_flags=[], aq=0, rl=0) {{
if aq:
mem_flags = makeList(mem_flags) + ["ACQUIRE"]
if rl:
mem_flags = makeList(mem_flags) + ["RELEASE"]
(header_output, decoder_output, decode_block, exec_output) = LoadStoreBase(
name, Name, ea_code, memacc_code, mem_flags, inst_flags, 'Store',
postacc_code, exec_template_base='StoreCond')
}};
def format LoadReserved(memacc_code, ea_code={{EA = Rs1;}}, mem_flags=[],
inst_flags=[], aq=0, rl=0) {{
if aq:
mem_flags = makeList(mem_flags) + ["ACQUIRE"]
if rl:
mem_flags = makeList(mem_flags) + ["RELEASE"]
(header_output, decoder_output, decode_block, exec_output) = LoadStoreBase(
name, Name, ea_code, memacc_code, mem_flags, inst_flags, 'Load',
exec_template_base='Load')
}};