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https://github.com/FEX-Emu/FEX.git
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lioncash
5f9052a675
In the event that the host doesn't support the requirements for running AVX-enabled applications (SVE2 with at least 256-bit wide vectors) but still wanted to run regular SSE-enabled applications, they would be taking a performance hit due to a load/store pessimization (necessary in order for 256-bit loads/stores to work) However, we can add an alternate view into the xmm data that would allow those hosts to use the previous optimization, while still supporting AVX-capable hosts.
275 lines
8.4 KiB
C++
275 lines
8.4 KiB
C++
#include "Tests/LinuxSyscalls/SignalDelegator.h"
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#include <FEXCore/Config/Config.h>
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#include <FEXCore/Core/CPUBackend.h>
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#include <FEXCore/Core/Context.h>
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#include <FEXCore/Core/CoreState.h>
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#include <FEXCore/Core/X86Enums.h>
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#include <FEXCore/Debug/InternalThreadState.h>
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#include <FEXCore/Utils/LogManager.h>
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#ifdef _M_X86_64
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#include <asm/ldt.h>
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#include <sys/syscall.h>
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#endif
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#include <memory>
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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#include <string>
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#include <ucontext.h>
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#include <vector>
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#include <signal.h>
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#include <xbyak/xbyak.h>
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using namespace Xbyak;
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#ifdef _M_X86_64
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static inline int modify_ldt(int func, void *ldt) { return ::syscall(SYS_modify_ldt, func, ldt, sizeof(struct user_desc)); }
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class x86HostRunner final : public Xbyak::CodeGenerator {
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public:
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using AsmDispatch = void (*)(uintptr_t InitialRip, uintptr_t InitialStack);
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AsmDispatch DispatchPtr;
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x86HostRunner() : CodeGenerator(4096) {
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Setup32BitCodeSegment();
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DispatchPtr = getCurr<AsmDispatch>();
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// x86-64 ABI has the stack aligned when /call/ happens
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// Which means the destination has a misaligned stack at that point
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push(rbx);
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push(rbp);
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push(r12);
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push(r13);
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push(r14);
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push(r15);
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sub(rsp, 8);
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// Save this stack pointer so we can cleanly shutdown the emulation with a long jump
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// regardless of where we were in the stack
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mov(rax, (uint64_t)&ReturningStackLocation);
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mov(qword[rax], rsp);
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mov(rax, 0);
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mov(rbx, 0);
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mov(rcx, 0);
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mov(rdx, 0);
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mov(rbp, 0);
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mov(rsi, 0);
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mov(r8, 0);
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mov(r9, 0);
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mov(r10, 0);
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mov(r11, 0);
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mov(r12, 0);
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mov(r13, 0);
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mov(r14, 0);
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mov(r15, 0);
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finit();
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if (Is64BitMode()) {
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push(rdi);
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// Load our RIP
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// RSP won't be set to zero here but should be fine
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ret();
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} else {
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// Far call needs to go through a gate
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// This is setup just like the following packing
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// {
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// uint32_t RIP;
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// uint16_t CodeSegment;
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// }
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GetCodeSegmentEntryLocation = getCurr<uint64_t>();
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hlt();
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Label Gate{};
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// Patch gate entry point
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// mov(dword[rip + Gate], edi)
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jmpf(ptr[rip + Gate]);
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L(Gate);
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dd(0x1'0000); // This is a 32-bit offset from the start of the gate. We start at 0x1'0000 + 0
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dw(CodeSegmentEntry);
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}
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ThreadStopHandlerAddress = getCurr<uint64_t>();
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add(rsp, 8);
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pop(r15);
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pop(r14);
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pop(r13);
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pop(r12);
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pop(rbp);
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pop(rbx);
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ret();
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ready();
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}
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bool HandleSIGSEGV(FEXCore::Core::CPUState *OutState, int Signal, void *info, void *ucontext) {
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ucontext_t *_context = (ucontext_t *)ucontext;
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mcontext_t *_mcontext = &_context->uc_mcontext;
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// Check our current instruction that we just executed to ensure it was an HLT
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uint8_t *Inst{};
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Inst = reinterpret_cast<uint8_t *>(_mcontext->gregs[REG_RIP]);
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if (!Is64BitMode()) {
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if (_mcontext->gregs[REG_RIP] == GetCodeSegmentEntryLocation) {
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// Backup the CSGSFS register
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GlobalCodeSegmentEntry = _mcontext->gregs[REG_CSGSFS];
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// Skip past this hlt and keep running
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_mcontext->gregs[REG_RIP] += 1;
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return true;
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}
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}
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constexpr uint8_t HLT = 0xF4;
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if (Inst[0] != HLT) {
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return false;
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}
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// Store our host state in to the guest for testing against
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OutState->gregs[FEXCore::X86State::REG_RAX] = _mcontext->gregs[REG_RAX];
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OutState->gregs[FEXCore::X86State::REG_RBX] = _mcontext->gregs[REG_RBX];
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OutState->gregs[FEXCore::X86State::REG_RCX] = _mcontext->gregs[REG_RCX];
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OutState->gregs[FEXCore::X86State::REG_RDX] = _mcontext->gregs[REG_RDX];
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OutState->gregs[FEXCore::X86State::REG_RBP] = _mcontext->gregs[REG_RBP];
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OutState->gregs[FEXCore::X86State::REG_RSI] = _mcontext->gregs[REG_RSI];
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OutState->gregs[FEXCore::X86State::REG_RDI] = _mcontext->gregs[REG_RDI];
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OutState->gregs[FEXCore::X86State::REG_RSP] = _mcontext->gregs[REG_RSP];
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OutState->gregs[FEXCore::X86State::REG_R8] = _mcontext->gregs[REG_R8];
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OutState->gregs[FEXCore::X86State::REG_R9] = _mcontext->gregs[REG_R9];
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OutState->gregs[FEXCore::X86State::REG_R10] = _mcontext->gregs[REG_R10];
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OutState->gregs[FEXCore::X86State::REG_R11] = _mcontext->gregs[REG_R11];
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OutState->gregs[FEXCore::X86State::REG_R12] = _mcontext->gregs[REG_R12];
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OutState->gregs[FEXCore::X86State::REG_R13] = _mcontext->gregs[REG_R13];
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OutState->gregs[FEXCore::X86State::REG_R14] = _mcontext->gregs[REG_R14];
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OutState->gregs[FEXCore::X86State::REG_R15] = _mcontext->gregs[REG_R15];
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OutState->rip = _mcontext->gregs[REG_RIP];
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for (size_t i = 0; i < FEXCore::Core::CPUState::NUM_XMMS; ++i) {
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memcpy(&OutState->xmm.avx.data[i], &_mcontext->fpregs->_xmm[i], sizeof(_mcontext->fpregs->_xmm[0]));
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}
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uint16_t CurrentOffset = (_mcontext->fpregs->swd >> 11) & 7;
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for (size_t i = 0; i < FEXCore::Core::CPUState::NUM_MMS; ++i) {
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memcpy(&OutState->mm[(i + CurrentOffset) % 8], &_mcontext->fpregs->_st[i], sizeof(_mcontext->fpregs->_st[0]));
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}
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// Our thread is stopping
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// We don't care about anything at this point
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// Set the stack to our starting location when we entered the JIT and get out safely
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_mcontext->gregs[REG_RSP] = ReturningStackLocation;
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// Set the new PC
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_mcontext->gregs[REG_RIP] = ThreadStopHandlerAddress;
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if (!Is64BitMode()) {
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// Unset code segment so we can jump back in to 64-bit mode
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_mcontext->gregs[REG_CSGSFS] = GlobalCodeSegmentEntry;
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}
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return true;
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}
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private:
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FEX_CONFIG_OPT(Is64BitMode, IS64BIT_MODE);
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int CodeSegmentEntry{};
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int GlobalCodeSegmentEntry{};
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uint64_t GetCodeSegmentEntryLocation;
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uint64_t ReturningStackLocation;
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uint64_t ThreadStopHandlerAddress;
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uint32_t MakeSelector(int Segment, bool LDT) const {
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// Selector Index, Table Indicator (1 = LDT, 0 = GDT), CPL (3 = userland)
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return (Segment << 3) | ((uint32_t)LDT << 2) | 3;
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};
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void Setup32BitCodeSegment() {
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if (Is64BitMode()) {
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return;
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}
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struct user_desc ldt {};
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ldt.entry_number = 1;
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// This is where HarnessCodeLoader loads code to
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ldt.base_addr = 0;
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ldt.limit = ~0U; // No limit
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ldt.seg_32bit = 1; // 32-bit
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ldt.contents = MODIFY_LDT_CONTENTS_CODE;
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ldt.read_exec_only = 0;
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ldt.limit_in_pages = 1;
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ldt.seg_not_present = 0;
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ldt.useable = 1;
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ldt.lm = 0; // Not-64-bit
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int Res = modify_ldt(0x11, &ldt);
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if (Res == -1) {
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LogMan::Msg::EFmt("Couldn't load 32-bit LDT");
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return;
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}
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CodeSegmentEntry = MakeSelector(ldt.entry_number, 1);
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// Make the data segment follow directly after the code segment
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// Overlapping region makes it read/write
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ldt.entry_number = 2;
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// This is where HarnessCodeLoader loads code to
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ldt.base_addr = 0;
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ldt.limit = ~0U; // No limit
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ldt.seg_32bit = 1; // 32-bit
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ldt.contents = MODIFY_LDT_CONTENTS_DATA;
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ldt.read_exec_only = 0;
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ldt.limit_in_pages = 1;
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ldt.seg_not_present = 0;
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ldt.useable = 1;
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ldt.lm = 0; // Not-64-bit
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Res = modify_ldt(0x11, &ldt);
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if (Res == -1) {
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LogMan::Msg::EFmt("Couldn't load 32-bit LDT");
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return;
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}
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// Stack entry overlapping data
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ldt.entry_number = 3;
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// This is where HarnessCodeLoader loads code to
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ldt.base_addr = 0;
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ldt.limit = ~0U; // No limit
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ldt.seg_32bit = 1; // 32-bit
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ldt.contents = MODIFY_LDT_CONTENTS_STACK;
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ldt.read_exec_only = 0;
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ldt.limit_in_pages = 1;
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ldt.seg_not_present = 0;
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ldt.useable = 1;
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ldt.lm = 0; // Not-64-bit
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Res = modify_ldt(0x11, &ldt);
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if (Res == -1) {
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LogMan::Msg::EFmt("Couldn't load 32-bit LDT");
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return;
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}
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}
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};
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void RunAsHost(std::unique_ptr<FEX::HLE::SignalDelegator> &SignalDelegation, uintptr_t InitialRip, uintptr_t StackPointer,
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FEXCore::Core::CPUState *OutputState) {
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x86HostRunner runner;
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SignalDelegation->RegisterHostSignalHandler(
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SIGSEGV,
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[&runner, OutputState](FEXCore::Core::InternalThreadState *Thread, int Signal, void *info, void *ucontext) -> bool {
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return runner.HandleSIGSEGV(OutputState, Signal, info, ucontext);
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},
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true
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);
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runner.DispatchPtr(InitialRip, StackPointer);
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}
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#else
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void RunAsHost(std::unique_ptr<FEX::HLE::SignalDelegator> &SignalDelegation, uintptr_t InitialRip, uintptr_t StackPointer,
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FEXCore::Core::CPUState *OutputState) {
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LOGMAN_MSG_A_FMT("RunAsHost doesn't exist for this host");
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}
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#endif
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