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UserspaceEmulator: Add basic TLS (thread-local storage) support

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The SoftMMU now receives full X86::LogicalAddress values from SoftCPU.
This allows the MMU to reroute TLS accesses to a special memory region.

The ELF executable's PT_TLS header tells us how to allocate the TLS.

Basically, the GS register points to a magical 4-byte area which has
a pointer to the TCB (thread control block). The TCB lives in normal
flat memory space and is accessed through the DS register.
This commit is contained in:
Andreas Kling 2020-07-12 00:54:09 +02:00
parent df95e25eaa
commit 734f63d522
4 changed files with 77 additions and 50 deletions
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51
DevTools/UserspaceEmulator/SoftMMU.cpp
View file

@ -28,10 +28,13 @@
namespace UserspaceEmulator {
SoftMMU::Region* SoftMMU::find_region(u32 address)
SoftMMU::Region* SoftMMU::find_region(X86::LogicalAddress address)
{
if (address.selector() == 0x28)
return m_tls_region.ptr();
for (auto& region : m_regions) {
if (region.contains(address))
if (region.contains(address.offset()))
return &region;
}
return nullptr;
@ -39,75 +42,81 @@ SoftMMU::Region* SoftMMU::find_region(u32 address)
void SoftMMU::add_region(NonnullOwnPtr<Region> region)
{
ASSERT(!find_region(region->base()));
ASSERT(!find_region({ 0x20, region->base() }));
// FIXME: More sanity checks pls
m_regions.append(move(region));
}
u8 SoftMMU::read8(u32 address)
void SoftMMU::set_tls_region(NonnullOwnPtr<Region> region)
{
ASSERT(!m_tls_region);
m_tls_region = move(region);
}
u8 SoftMMU::read8(X86::LogicalAddress address)
{
auto* region = find_region(address);
if (!region) {
warn() << "SoftMMU::read8: No region for @" << (const void*)address;
warn() << "SoftMMU::read8: No region for @" << (const void*)address.offset();
TODO();
}
return region->read8(address - region->base());
return region->read8(address.offset() - region->base());
}
u16 SoftMMU::read16(u32 address)
u16 SoftMMU::read16(X86::LogicalAddress address)
{
auto* region = find_region(address);
if (!region) {
warn() << "SoftMMU::read16: No region for @" << (const void*)address;
warn() << "SoftMMU::read16: No region for @" << (const void*)address.offset();
TODO();
}
return region->read16(address - region->base());
return region->read16(address.offset() - region->base());
}
u32 SoftMMU::read32(u32 address)
u32 SoftMMU::read32(X86::LogicalAddress address)
{
auto* region = find_region(address);
if (!region) {
warn() << "SoftMMU::read32: No region for @" << (const void*)address;
warn() << "SoftMMU::read32: No region for @" << (const void*)address.offset();
TODO();
}
return region->read32(address - region->base());
return region->read32(address.offset() - region->base());
}
void SoftMMU::write8(u32 address, u8 value)
void SoftMMU::write8(X86::LogicalAddress address, u8 value)
{
auto* region = find_region(address);
if (!region) {
warn() << "SoftMMU::write8: No region for @" << (const void*)address;
warn() << "SoftMMU::write8: No region for @" << (const void*)address.offset();
TODO();
}
region->write8(address - region->base(), value);
region->write8(address.offset() - region->base(), value);
}
void SoftMMU::write16(u32 address, u16 value)
void SoftMMU::write16(X86::LogicalAddress address, u16 value)
{
auto* region = find_region(address);
if (!region) {
warn() << "SoftMMU::write16: No region for @" << (const void*)address;
warn() << "SoftMMU::write16: No region for @" << (const void*)address.offset();
TODO();
}
region->write16(address - region->base(), value);
region->write16(address.offset() - region->base(), value);
}
void SoftMMU::write32(u32 address, u32 value)
void SoftMMU::write32(X86::LogicalAddress address, u32 value)
{
auto* region = find_region(address);
if (!region) {
warn() << "SoftMMU::write32: No region for @" << (const void*)address;
warn() << "SoftMMU::write32: No region for @" << (const void*)address.offset();
TODO();
}
region->write32(address - region->base(), value);
region->write32(address.offset() - region->base(), value);
}
}