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Stop execution when performing HIO request

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Since the HIO request is basically treated like a syscall, we need to
stop emulation while waiting for the GDB client to reply with the
result. This ensures any memory queries etc. that GDB makes to fulfill
the HIO request are accessing memory as it was at the time of the
request, instead of afterwards.
This commit is contained in:
Ian Chamberlain 2022-12-04 15:34:06 -05:00
parent b9c11e71d7
commit f92f494cab
No known key found for this signature in database
GPG key ID: AE5484D09405AA60
5 changed files with 60 additions and 35 deletions
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44
src/core/gdbstub/hio.cpp
View file

@ -12,7 +12,14 @@ namespace {
static VAddr current_hio_request_addr;
static PackedGdbHioRequest current_hio_request;
static std::atomic<bool> sent_request{false};
enum class Status {
NoRequest,
NotSent,
SentWaitingReply,
};
static std::atomic<Status> request_status{Status::NoRequest};
} // namespace
@ -40,15 +47,23 @@ void SetHioRequest(const VAddr addr) {
LOG_WARNING(Debug_GDBStub, "Invalid HIO request sent by application");
current_hio_request_addr = 0;
current_hio_request = {};
request_status = Status::NoRequest;
} else {
LOG_DEBUG(Debug_GDBStub, "HIO request initiated at 0x{:X}", addr);
current_hio_request_addr = addr;
sent_request = false;
LOG_DEBUG(Debug_GDBStub, "HIO request initiated");
request_status = Status::NotSent;
// Now halt, so that no further instructions are executed until the request
// is processed by the client. We auto-continue after the reply comes back
Break();
SetCpuHaltFlag(true);
SetCpuStepFlag(false);
Core::GetRunningCore().ClearInstructionCache();
}
}
bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (current_hio_request_addr == 0 || !sent_request) {
if (!WaitingForHioReply()) {
LOG_WARNING(Debug_GDBStub, "Got HIO reply but never sent a request");
// TODO send error reply packet?
return false;
@ -73,10 +88,6 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
}
const auto retval_end = std::find(command_pos, command_buffer + command_length, ',');
if (retval_end >= command_buffer + command_length) {
// return GDB_ReplyErrno(ctx, EILSEQ);
return false;
}
u64 retval = (u64)HexToInt(command_pos, retval_end - command_pos);
command_pos = retval_end + 1;
@ -86,7 +97,7 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
if (*command_pos != 0) {
u32 errno_;
// GDB protocol technically allows errno to have a +/- prefix but this will never happen.
// GDB protocol technically allows errno to have a +/- prefix but this should never happen.
const auto errno_end = std::find(command_pos, command_buffer + command_length, ',');
errno_ = HexToInt(command_pos, errno_end - command_pos);
command_pos = errno_end + 1;
@ -123,15 +134,19 @@ bool HandleHioReply(const u8* const command_buffer, const u32 command_length) {
memory.WriteBlock(*process, current_hio_request_addr, &current_hio_request,
sizeof(PackedGdbHioRequest));
current_hio_request = PackedGdbHioRequest{};
current_hio_request = {};
current_hio_request_addr = 0;
sent_request = false;
request_status = Status::NoRequest;
return true;
}
bool HasHioRequest() {
return current_hio_request_addr != 0 && !sent_request;
bool HasPendingHioRequest() {
return current_hio_request_addr != 0 && request_status == Status::NotSent;
}
bool WaitingForHioReply() {
return current_hio_request_addr != 0 && request_status == Status::SentWaitingReply;
}
std::string BuildHioRequestPacket() {
@ -163,7 +178,8 @@ std::string BuildHioRequestPacket() {
}
LOG_DEBUG(Debug_GDBStub, "HIO request packet: {}", packet.str());
sent_request = true;
request_status = Status::SentWaitingReply;
return packet.str();
}