citra/src/core/hle/kernel/server_session.cpp
Weiyi Wang f565ea80f0 HLE/IPC: HLEContext can memorize the client thread and use it for SleepClientThread
This reduces the boilerplate that services have to write out the current thread explicitly. Using current thread instead of client thread is also semantically incorrect, and will be a problem when we implement multicore (at which time there will be multiple current threads)
2019-04-02 13:23:39 -04:00

140 lines
6 KiB
C++

// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <tuple>
#include "core/hle/kernel/client_port.h"
#include "core/hle/kernel/client_session.h"
#include "core/hle/kernel/hle_ipc.h"
#include "core/hle/kernel/server_session.h"
#include "core/hle/kernel/session.h"
#include "core/hle/kernel/thread.h"
namespace Kernel {
ServerSession::ServerSession(KernelSystem& kernel) : WaitObject(kernel), kernel(kernel) {}
ServerSession::~ServerSession() {
// This destructor will be called automatically when the last ServerSession handle is closed by
// the emulated application.
// Decrease the port's connection count.
if (parent->port)
parent->port->ConnectionClosed();
// TODO(Subv): Wake up all the ClientSession's waiting threads and set
// the SendSyncRequest result to 0xC920181A.
parent->server = nullptr;
}
ResultVal<std::shared_ptr<ServerSession>> ServerSession::Create(KernelSystem& kernel,
std::string name) {
auto server_session{std::make_shared<ServerSession>(kernel)};
server_session->name = std::move(name);
server_session->parent = nullptr;
return MakeResult(std::move(server_session));
}
bool ServerSession::ShouldWait(Thread* thread) const {
// Closed sessions should never wait, an error will be returned from svcReplyAndReceive.
if (parent->client == nullptr)
return false;
// Wait if we have no pending requests, or if we're currently handling a request.
return pending_requesting_threads.empty() || currently_handling != nullptr;
}
void ServerSession::Acquire(Thread* thread) {
ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
// If the client endpoint was closed, don't do anything. This ServerSession is now useless and
// will linger until its last handle is closed by the running application.
if (parent->client == nullptr)
return;
// We are now handling a request, pop it from the stack.
ASSERT(!pending_requesting_threads.empty());
currently_handling = pending_requesting_threads.back();
pending_requesting_threads.pop_back();
}
ResultCode ServerSession::HandleSyncRequest(std::shared_ptr<Thread> thread) {
// The ServerSession received a sync request, this means that there's new data available
// from its ClientSession, so wake up any threads that may be waiting on a svcReplyAndReceive or
// similar.
// If this ServerSession has an associated HLE handler, forward the request to it.
if (hle_handler != nullptr) {
std::array<u32_le, IPC::COMMAND_BUFFER_LENGTH + 2 * IPC::MAX_STATIC_BUFFERS> cmd_buf;
Kernel::Process* current_process = thread->owner_process;
kernel.memory.ReadBlock(*current_process, thread->GetCommandBufferAddress(), cmd_buf.data(),
cmd_buf.size() * sizeof(u32));
Kernel::HLERequestContext context(kernel, SharedFrom(this), thread.get());
context.PopulateFromIncomingCommandBuffer(cmd_buf.data(), *current_process);
hle_handler->HandleSyncRequest(context);
ASSERT(thread->status == Kernel::ThreadStatus::Running ||
thread->status == Kernel::ThreadStatus::WaitHleEvent);
// Only write the response immediately if the thread is still running. If the HLE handler
// put the thread to sleep then the writing of the command buffer will be deferred to the
// wakeup callback.
if (thread->status == Kernel::ThreadStatus::Running) {
context.WriteToOutgoingCommandBuffer(cmd_buf.data(), *current_process);
kernel.memory.WriteBlock(*current_process, thread->GetCommandBufferAddress(),
cmd_buf.data(), cmd_buf.size() * sizeof(u32));
}
}
if (thread->status == ThreadStatus::Running) {
// Put the thread to sleep until the server replies, it will be awoken in
// svcReplyAndReceive for LLE servers.
thread->status = ThreadStatus::WaitIPC;
if (hle_handler != nullptr) {
// For HLE services, we put the request threads to sleep for a short duration to
// simulate IPC overhead, but only if the HLE handler didn't put the thread to sleep for
// other reasons like an async callback. The IPC overhead is needed to prevent
// starvation when a thread only does sync requests to HLE services while a
// lower-priority thread is waiting to run.
// This delay was approximated in a homebrew application by measuring the average time
// it takes for svcSendSyncRequest to return when performing the SetLcdForceBlack IPC
// request to the GSP:GPU service in a n3DS with firmware 11.6. The measured values have
// a high variance and vary between models.
static constexpr u64 IPCDelayNanoseconds = 39000;
thread->WakeAfterDelay(IPCDelayNanoseconds);
} else {
// Add the thread to the list of threads that have issued a sync request with this
// server.
pending_requesting_threads.push_back(std::move(thread));
}
}
// If this ServerSession does not have an HLE implementation, just wake up the threads waiting
// on it.
WakeupAllWaitingThreads();
return RESULT_SUCCESS;
}
std::tuple<std::shared_ptr<ServerSession>, std::shared_ptr<ClientSession>>
KernelSystem::CreateSessionPair(const std::string& name, std::shared_ptr<ClientPort> port) {
auto server_session = ServerSession::Create(*this, name + "_Server").Unwrap();
auto client_session{std::make_shared<ClientSession>(*this)};
client_session->name = name + "_Client";
std::shared_ptr<Session> parent(new Session);
parent->client = client_session.get();
parent->server = server_session.get();
parent->port = port;
client_session->parent = parent;
server_session->parent = parent;
return std::make_tuple(std::move(server_session), std::move(client_session));
}
} // namespace Kernel