UserspaceEmulator: Use ring 3 segment selectors

We were using ring 0 selectors everywhere (the bottom 3 bits of a
selector determines the ring.) This doesn't really make any practical
difference since UE doesn't run code in other rings anyway, but let's
have correct-looking segment selectors. :^)

DevTools/UserspaceEmulator/Emulator.cpp

@@ -267,11 +267,11 @@ Vector<FlatPtr> Emulator::raw_backtrace()
 
     u32 frame_ptr = m_cpu.ebp().value();
     while (frame_ptr) {
-        u32 ret_ptr = m_mmu.read32({ 0x20, frame_ptr + 4 }).value();
+        u32 ret_ptr = m_mmu.read32({ 0x23, frame_ptr + 4 }).value();
         if (!ret_ptr)
             break;
         backtrace.append(ret_ptr);
-        frame_ptr = m_mmu.read32({ 0x20, frame_ptr }).value();
+        frame_ptr = m_mmu.read32({ 0x23, frame_ptr }).value();
     }
     return backtrace;
 }
@@ -984,7 +984,7 @@ int Emulator::virt$pipe(FlatPtr vm_pipefd, int flags)
 
 u32 Emulator::virt$munmap(FlatPtr address, u32 size)
 {
-    auto* region = mmu().find_region({ 0x20, address });
+    auto* region = mmu().find_region({ 0x23, address });
     ASSERT(region);
     if (region->size() != round_up_to_power_of_two(size, PAGE_SIZE))
         TODO();

DevTools/UserspaceEmulator/MallocTracer.cpp

@@ -60,7 +60,7 @@ void MallocTracer::target_did_malloc(Badge<SoftCPU>, FlatPtr address, size_t siz
 {
     if (m_emulator.is_in_loader_code())
         return;
-    auto* region = m_emulator.mmu().find_region({ 0x20, address });
+    auto* region = m_emulator.mmu().find_region({ 0x23, address });
     ASSERT(region);
     ASSERT(region->is_mmap());
     auto& mmap_region = static_cast<MmapRegion&>(*region);
@@ -143,7 +143,7 @@ void MallocTracer::target_did_realloc(Badge<SoftCPU>, FlatPtr address, size_t si
 {
     if (m_emulator.is_in_loader_code())
         return;
-    auto* region = m_emulator.mmu().find_region({ 0x20, address });
+    auto* region = m_emulator.mmu().find_region({ 0x23, address });
     ASSERT(region);
     ASSERT(region->is_mmap());
     auto& mmap_region = static_cast<MmapRegion&>(*region);
@@ -309,7 +309,7 @@ bool MallocTracer::is_reachable(const Mallocation& mallocation) const
             return IterationDecision::Continue;
         size_t pointers_in_mallocation = other_mallocation.size / sizeof(u32);
         for (size_t i = 0; i < pointers_in_mallocation; ++i) {
-            auto value = m_emulator.mmu().read32({ 0x20, other_mallocation.address + i * sizeof(u32) });
+            auto value = m_emulator.mmu().read32({ 0x23, other_mallocation.address + i * sizeof(u32) });
             if (value.value() == mallocation.address && !value.is_uninitialized()) {
 #ifdef REACHABLE_DEBUG
                 reportln("mallocation {:p} is reachable from other mallocation {:p}", mallocation.address, other_mallocation.address);

DevTools/UserspaceEmulator/SoftCPU.cpp

@@ -97,11 +97,11 @@ SoftCPU::SoftCPU(Emulator& emulator)
     memset(m_gpr, 0, sizeof(m_gpr));
     memset(m_gpr_shadow, 1, sizeof(m_gpr_shadow));
 
-    m_segment[(int)X86::SegmentRegister::CS] = 0x18;
-    m_segment[(int)X86::SegmentRegister::DS] = 0x20;
-    m_segment[(int)X86::SegmentRegister::ES] = 0x20;
-    m_segment[(int)X86::SegmentRegister::SS] = 0x20;
-    m_segment[(int)X86::SegmentRegister::GS] = 0x28;
+    m_segment[(int)X86::SegmentRegister::CS] = 0x1b;
+    m_segment[(int)X86::SegmentRegister::DS] = 0x23;
+    m_segment[(int)X86::SegmentRegister::ES] = 0x23;
+    m_segment[(int)X86::SegmentRegister::SS] = 0x23;
+    m_segment[(int)X86::SegmentRegister::GS] = 0x2b;
 }
 
 void SoftCPU::dump() const
@@ -147,7 +147,7 @@ void SoftCPU::update_code_cache()
 
 ValueWithShadow<u8> SoftCPU::read_memory8(X86::LogicalAddress address)
 {
-    ASSERT(address.selector() == 0x18 || address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x1b || address.selector() == 0x23 || address.selector() == 0x2b);
     auto value = m_emulator.mmu().read8(address);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mread_memory8: @{:04x}:{:08x} -> {:02x} ({:02x})\033[0m", address.selector(), address.offset(), value, value.shadow());
@@ -157,7 +157,7 @@ ValueWithShadow<u8> SoftCPU::read_memory8(X86::LogicalAddress address)
 
 ValueWithShadow<u16> SoftCPU::read_memory16(X86::LogicalAddress address)
 {
-    ASSERT(address.selector() == 0x18 || address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x1b || address.selector() == 0x23 || address.selector() == 0x2b);
     auto value = m_emulator.mmu().read16(address);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mread_memory16: @{:04x}:{:08x} -> {:04x} ({:04x})\033[0m", address.selector(), address.offset(), value, value.shadow());
@@ -167,7 +167,7 @@ ValueWithShadow<u16> SoftCPU::read_memory16(X86::LogicalAddress address)
 
 ValueWithShadow<u32> SoftCPU::read_memory32(X86::LogicalAddress address)
 {
-    ASSERT(address.selector() == 0x18 || address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x1b || address.selector() == 0x23 || address.selector() == 0x2b);
     auto value = m_emulator.mmu().read32(address);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mread_memory32: @{:04x}:{:08x} -> {:08x} ({:08x})\033[0m", address.selector(), address.offset(), value, value.shadow());
@@ -177,7 +177,7 @@ ValueWithShadow<u32> SoftCPU::read_memory32(X86::LogicalAddress address)
 
 ValueWithShadow<u64> SoftCPU::read_memory64(X86::LogicalAddress address)
 {
-    ASSERT(address.selector() == 0x18 || address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x1b || address.selector() == 0x23 || address.selector() == 0x2b);
     auto value = m_emulator.mmu().read64(address);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mread_memory64: @{:04x}:{:08x} -> {:016x} ({:016x})\033[0m", address.selector(), address.offset(), value, value.shadow());
@@ -187,7 +187,7 @@ ValueWithShadow<u64> SoftCPU::read_memory64(X86::LogicalAddress address)
 
 void SoftCPU::write_memory8(X86::LogicalAddress address, ValueWithShadow<u8> value)
 {
-    ASSERT(address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x23 || address.selector() == 0x2b);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mwrite_memory8: @{:04x}:{:08x} <- {:02x} ({:02x})\033[0m", address.selector(), address.offset(), value, value.shadow());
 #endif
@@ -196,7 +196,7 @@ void SoftCPU::write_memory8(X86::LogicalAddress address, ValueWithShadow<u8> val
 
 void SoftCPU::write_memory16(X86::LogicalAddress address, ValueWithShadow<u16> value)
 {
-    ASSERT(address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x23 || address.selector() == 0x2b);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mwrite_memory16: @{:04x}:{:08x} <- {:04x} ({:04x})\033[0m", address.selector(), address.offset(), value, value.shadow());
 #endif
@@ -205,7 +205,7 @@ void SoftCPU::write_memory16(X86::LogicalAddress address, ValueWithShadow<u16> v
 
 void SoftCPU::write_memory32(X86::LogicalAddress address, ValueWithShadow<u32> value)
 {
-    ASSERT(address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x23 || address.selector() == 0x2b);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mwrite_memory32: @{:04x}:{:08x} <- {:08x} ({:08x})\033[0m", address.selector(), address.offset(), value, value.shadow());
 #endif
@@ -214,7 +214,7 @@ void SoftCPU::write_memory32(X86::LogicalAddress address, ValueWithShadow<u32> v
 
 void SoftCPU::write_memory64(X86::LogicalAddress address, ValueWithShadow<u64> value)
 {
-    ASSERT(address.selector() == 0x20 || address.selector() == 0x28);
+    ASSERT(address.selector() == 0x23 || address.selector() == 0x2b);
 #ifdef MEMORY_DEBUG
     outln("\033[36;1mwrite_memory64: @{:04x}:{:08x} <- {:016x} ({:016x})\033[0m", address.selector(), address.offset(), value, value.shadow());
 #endif
@@ -226,7 +226,7 @@ void SoftCPU::push_string(const StringView& string)
     size_t space_to_allocate = round_up_to_power_of_two(string.length() + 1, 16);
     set_esp({ esp().value() - space_to_allocate, esp().shadow() });
     m_emulator.mmu().copy_to_vm(esp().value(), string.characters_without_null_termination(), string.length());
-    m_emulator.mmu().write8({ 0x20, esp().value() + string.length() }, shadow_wrap_as_initialized((u8)'\0'));
+    m_emulator.mmu().write8({ 0x23, esp().value() + string.length() }, shadow_wrap_as_initialized((u8)'\0'));
 }
 
 void SoftCPU::push_buffer(const u8* data, size_t size)

DevTools/UserspaceEmulator/SoftMMU.cpp

@@ -41,7 +41,7 @@ SoftMMU::SoftMMU(Emulator& emulator)
 
 void SoftMMU::add_region(NonnullOwnPtr<Region> region)
 {
-    ASSERT(!find_region({ 0x20, region->base() }));
+    ASSERT(!find_region({ 0x23, region->base() }));
 
     // FIXME: More sanity checks pls
     if (region->is_shared_buffer())
@@ -114,7 +114,7 @@ ValueWithShadow<u32> SoftMMU::read32(X86::LogicalAddress address)
 {
     auto* region = find_region(address);
     if (!region) {
-        reportln("SoftMMU::read32: No region for @ {:p}", address.offset());
+        reportln("SoftMMU::read32: No region for @ {:04x}:{:p}", address.selector(), address.offset());
         m_emulator.dump_backtrace();
         TODO();
     }
@@ -221,14 +221,14 @@ void SoftMMU::copy_to_vm(FlatPtr destination, const void* source, size_t size)
 {
     // FIXME: We should have a way to preserve the shadow data here as well.
     for (size_t i = 0; i < size; ++i)
-        write8({ 0x20, destination + i }, shadow_wrap_as_initialized(((const u8*)source)[i]));
+        write8({ 0x23, destination + i }, shadow_wrap_as_initialized(((const u8*)source)[i]));
 }
 
 void SoftMMU::copy_from_vm(void* destination, const FlatPtr source, size_t size)
 {
     // FIXME: We should have a way to preserve the shadow data here as well.
     for (size_t i = 0; i < size; ++i)
-        ((u8*)destination)[i] = read8({ 0x20, source + i }).value();
+        ((u8*)destination)[i] = read8({ 0x23, source + i }).value();
 }
 
 ByteBuffer SoftMMU::copy_buffer_from_vm(const FlatPtr source, size_t size)

DevTools/UserspaceEmulator/SoftMMU.h

@@ -55,7 +55,7 @@ public:
 
     ALWAYS_INLINE Region* find_region(X86::LogicalAddress address)
     {
-        if (address.selector() == 0x28)
+        if (address.selector() == 0x2b)
             return m_tls_region.ptr();
 
         size_t page_index = (address.offset() & ~(PAGE_SIZE - 1)) / PAGE_SIZE;