Merge pull request #2555 from lioncash/tls

kernel/process: Decouple TLS handling from threads
This commit is contained in:
Zach Hilman 2019-07-04 15:32:32 -04:00 committed by GitHub
commit 54a02d14fd
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6 changed files with 148 additions and 81 deletions

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@ -3,6 +3,7 @@
// Refer to the license.txt file included.
#include <algorithm>
#include <bitset>
#include <memory>
#include <random>
#include "common/alignment.h"
@ -48,8 +49,58 @@ void SetupMainThread(Process& owner_process, KernelCore& kernel, u32 priority) {
}
} // Anonymous namespace
SharedPtr<Process> Process::Create(Core::System& system, std::string name,
Process::ProcessType type) {
// Represents a page used for thread-local storage.
//
// Each TLS page contains slots that may be used by processes and threads.
// Every process and thread is created with a slot in some arbitrary page
// (whichever page happens to have an available slot).
class TLSPage {
public:
static constexpr std::size_t num_slot_entries = Memory::PAGE_SIZE / Memory::TLS_ENTRY_SIZE;
explicit TLSPage(VAddr address) : base_address{address} {}
bool HasAvailableSlots() const {
return !is_slot_used.all();
}
VAddr GetBaseAddress() const {
return base_address;
}
std::optional<VAddr> ReserveSlot() {
for (std::size_t i = 0; i < is_slot_used.size(); i++) {
if (is_slot_used[i]) {
continue;
}
is_slot_used[i] = true;
return base_address + (i * Memory::TLS_ENTRY_SIZE);
}
return std::nullopt;
}
void ReleaseSlot(VAddr address) {
// Ensure that all given addresses are consistent with how TLS pages
// are intended to be used when releasing slots.
ASSERT(IsWithinPage(address));
ASSERT((address % Memory::TLS_ENTRY_SIZE) == 0);
const std::size_t index = (address - base_address) / Memory::TLS_ENTRY_SIZE;
is_slot_used[index] = false;
}
private:
bool IsWithinPage(VAddr address) const {
return base_address <= address && address < base_address + Memory::PAGE_SIZE;
}
VAddr base_address;
std::bitset<num_slot_entries> is_slot_used;
};
SharedPtr<Process> Process::Create(Core::System& system, std::string name, ProcessType type) {
auto& kernel = system.Kernel();
SharedPtr<Process> process(new Process(system));
@ -181,61 +232,55 @@ void Process::PrepareForTermination() {
}
/**
* Finds a free location for the TLS section of a thread.
* @param tls_slots The TLS page array of the thread's owner process.
* Returns a tuple of (page, slot, alloc_needed) where:
* page: The index of the first allocated TLS page that has free slots.
* slot: The index of the first free slot in the indicated page.
* alloc_needed: Whether there's a need to allocate a new TLS page (All pages are full).
* Attempts to find a TLS page that contains a free slot for
* use by a thread.
*
* @returns If a page with an available slot is found, then an iterator
* pointing to the page is returned. Otherwise the end iterator
* is returned instead.
*/
static std::tuple<std::size_t, std::size_t, bool> FindFreeThreadLocalSlot(
const std::vector<std::bitset<8>>& tls_slots) {
// Iterate over all the allocated pages, and try to find one where not all slots are used.
for (std::size_t page = 0; page < tls_slots.size(); ++page) {
const auto& page_tls_slots = tls_slots[page];
if (!page_tls_slots.all()) {
// We found a page with at least one free slot, find which slot it is
for (std::size_t slot = 0; slot < page_tls_slots.size(); ++slot) {
if (!page_tls_slots.test(slot)) {
return std::make_tuple(page, slot, false);
}
}
}
static auto FindTLSPageWithAvailableSlots(std::vector<TLSPage>& tls_pages) {
return std::find_if(tls_pages.begin(), tls_pages.end(),
[](const auto& page) { return page.HasAvailableSlots(); });
}
return std::make_tuple(0, 0, true);
}
VAddr Process::CreateTLSRegion() {
auto tls_page_iter = FindTLSPageWithAvailableSlots(tls_pages);
VAddr Process::MarkNextAvailableTLSSlotAsUsed(Thread& thread) {
auto [available_page, available_slot, needs_allocation] = FindFreeThreadLocalSlot(tls_slots);
const VAddr tls_begin = vm_manager.GetTLSIORegionBaseAddress();
if (tls_page_iter == tls_pages.cend()) {
const auto region_address =
vm_manager.FindFreeRegion(vm_manager.GetTLSIORegionBaseAddress(),
vm_manager.GetTLSIORegionEndAddress(), Memory::PAGE_SIZE);
ASSERT(region_address.Succeeded());
if (needs_allocation) {
tls_slots.emplace_back(0); // The page is completely available at the start
available_page = tls_slots.size() - 1;
available_slot = 0; // Use the first slot in the new page
// Allocate some memory from the end of the linear heap for this region.
auto& tls_memory = thread.GetTLSMemory();
tls_memory->insert(tls_memory->end(), Memory::PAGE_SIZE, 0);
vm_manager.RefreshMemoryBlockMappings(tls_memory.get());
vm_manager.MapMemoryBlock(tls_begin + available_page * Memory::PAGE_SIZE, tls_memory, 0,
const auto map_result = vm_manager.MapMemoryBlock(
*region_address, std::make_shared<std::vector<u8>>(Memory::PAGE_SIZE), 0,
Memory::PAGE_SIZE, MemoryState::ThreadLocal);
ASSERT(map_result.Succeeded());
tls_pages.emplace_back(*region_address);
const auto reserve_result = tls_pages.back().ReserveSlot();
ASSERT(reserve_result.has_value());
return *reserve_result;
}
tls_slots[available_page].set(available_slot);
return tls_begin + available_page * Memory::PAGE_SIZE + available_slot * Memory::TLS_ENTRY_SIZE;
return *tls_page_iter->ReserveSlot();
}
void Process::FreeTLSSlot(VAddr tls_address) {
const VAddr tls_base = tls_address - vm_manager.GetTLSIORegionBaseAddress();
const VAddr tls_page = tls_base / Memory::PAGE_SIZE;
const VAddr tls_slot = (tls_base % Memory::PAGE_SIZE) / Memory::TLS_ENTRY_SIZE;
void Process::FreeTLSRegion(VAddr tls_address) {
const VAddr aligned_address = Common::AlignDown(tls_address, Memory::PAGE_SIZE);
auto iter =
std::find_if(tls_pages.begin(), tls_pages.end(), [aligned_address](const auto& page) {
return page.GetBaseAddress() == aligned_address;
});
tls_slots[tls_page].reset(tls_slot);
// Something has gone very wrong if we're freeing a region
// with no actual page available.
ASSERT(iter != tls_pages.cend());
iter->ReleaseSlot(tls_address);
}
void Process::LoadModule(CodeSet module_, VAddr base_addr) {

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@ -5,7 +5,6 @@
#pragma once
#include <array>
#include <bitset>
#include <cstddef>
#include <list>
#include <string>
@ -32,6 +31,7 @@ namespace Kernel {
class KernelCore;
class ResourceLimit;
class Thread;
class TLSPage;
struct CodeSet;
@ -260,10 +260,10 @@ public:
// Thread-local storage management
// Marks the next available region as used and returns the address of the slot.
VAddr MarkNextAvailableTLSSlotAsUsed(Thread& thread);
[[nodiscard]] VAddr CreateTLSRegion();
// Frees a used TLS slot identified by the given address
void FreeTLSSlot(VAddr tls_address);
void FreeTLSRegion(VAddr tls_address);
private:
explicit Process(Core::System& system);
@ -290,7 +290,7 @@ private:
u64 code_memory_size = 0;
/// Current status of the process
ProcessStatus status;
ProcessStatus status{};
/// The ID of this process
u64 process_id = 0;
@ -310,7 +310,7 @@ private:
/// holds the TLS for a specific thread. This vector contains which parts are in use for each
/// page as a bitmask.
/// This vector will grow as more pages are allocated for new threads.
std::vector<std::bitset<8>> tls_slots;
std::vector<TLSPage> tls_pages;
/// Contains the parsed process capability descriptors.
ProcessCapabilities capabilities;
@ -339,7 +339,7 @@ private:
Mutex mutex;
/// Random values for svcGetInfo RandomEntropy
std::array<u64, RANDOM_ENTROPY_SIZE> random_entropy;
std::array<u64, RANDOM_ENTROPY_SIZE> random_entropy{};
/// List of threads that are running with this process as their owner.
std::list<const Thread*> thread_list;

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@ -65,7 +65,7 @@ void Thread::Stop() {
owner_process->UnregisterThread(this);
// Mark the TLS slot in the thread's page as free.
owner_process->FreeTLSSlot(tls_address);
owner_process->FreeTLSRegion(tls_address);
}
void Thread::WakeAfterDelay(s64 nanoseconds) {
@ -205,9 +205,9 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
thread->name = std::move(name);
thread->callback_handle = kernel.ThreadWakeupCallbackHandleTable().Create(thread).Unwrap();
thread->owner_process = &owner_process;
thread->tls_address = thread->owner_process->CreateTLSRegion();
thread->scheduler = &system.Scheduler(processor_id);
thread->scheduler->AddThread(thread);
thread->tls_address = thread->owner_process->MarkNextAvailableTLSSlotAsUsed(*thread);
thread->owner_process->RegisterThread(thread.get());

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@ -5,7 +5,6 @@
#pragma once
#include <functional>
#include <memory>
#include <string>
#include <vector>
@ -78,9 +77,6 @@ enum class ThreadActivity : u32 {
class Thread final : public WaitObject {
public:
using TLSMemory = std::vector<u8>;
using TLSMemoryPtr = std::shared_ptr<TLSMemory>;
using MutexWaitingThreads = std::vector<SharedPtr<Thread>>;
using ThreadContext = Core::ARM_Interface::ThreadContext;
@ -169,14 +165,6 @@ public:
return thread_id;
}
TLSMemoryPtr& GetTLSMemory() {
return tls_memory;
}
const TLSMemoryPtr& GetTLSMemory() const {
return tls_memory;
}
/// Resumes a thread from waiting
void ResumeFromWait();
@ -463,11 +451,9 @@ private:
u32 ideal_core{0xFFFFFFFF};
u64 affinity_mask{0x1};
TLSMemoryPtr tls_memory = std::make_shared<TLSMemory>();
ThreadActivity activity = ThreadActivity::Normal;
std::string name;
ThreadActivity activity = ThreadActivity::Normal;
};
/**

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@ -152,22 +152,33 @@ ResultVal<VMManager::VMAHandle> VMManager::MapBackingMemory(VAddr target, u8* me
}
ResultVal<VAddr> VMManager::FindFreeRegion(u64 size) const {
// Find the first Free VMA.
const VAddr base = GetASLRRegionBaseAddress();
const VMAHandle vma_handle = std::find_if(vma_map.begin(), vma_map.end(), [&](const auto& vma) {
if (vma.second.type != VMAType::Free)
return false;
return FindFreeRegion(GetASLRRegionBaseAddress(), GetASLRRegionEndAddress(), size);
}
const VAddr vma_end = vma.second.base + vma.second.size;
return vma_end > base && vma_end >= base + size;
ResultVal<VAddr> VMManager::FindFreeRegion(VAddr begin, VAddr end, u64 size) const {
ASSERT(begin < end);
ASSERT(size <= end - begin);
const VMAHandle vma_handle =
std::find_if(vma_map.begin(), vma_map.end(), [begin, end, size](const auto& vma) {
if (vma.second.type != VMAType::Free) {
return false;
}
const VAddr vma_base = vma.second.base;
const VAddr vma_end = vma_base + vma.second.size;
const VAddr assumed_base = (begin < vma_base) ? vma_base : begin;
const VAddr used_range = assumed_base + size;
return vma_base <= assumed_base && assumed_base < used_range && used_range < end &&
used_range <= vma_end;
});
if (vma_handle == vma_map.end()) {
if (vma_handle == vma_map.cend()) {
// TODO(Subv): Find the correct error code here.
return ResultCode(-1);
}
const VAddr target = std::max(base, vma_handle->second.base);
const VAddr target = std::max(begin, vma_handle->second.base);
return MakeResult<VAddr>(target);
}

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@ -362,13 +362,38 @@ public:
ResultVal<VMAHandle> MapBackingMemory(VAddr target, u8* memory, u64 size, MemoryState state);
/**
* Finds the first free address that can hold a region of the desired size.
* Finds the first free memory region of the given size within
* the user-addressable ASLR memory region.
*
* @param size Size of the desired region.
* @return The found free address.
* @param size The size of the desired region in bytes.
*
* @returns If successful, the base address of the free region with
* the given size.
*/
ResultVal<VAddr> FindFreeRegion(u64 size) const;
/**
* Finds the first free address range that can hold a region of the desired size
*
* @param begin The starting address of the range.
* This is treated as an inclusive beginning address.
*
* @param end The ending address of the range.
* This is treated as an exclusive ending address.
*
* @param size The size of the free region to attempt to locate,
* in bytes.
*
* @returns If successful, the base address of the free region with
* the given size.
*
* @returns If unsuccessful, a result containing an error code.
*
* @pre The starting address must be less than the ending address.
* @pre The size must not exceed the address range itself.
*/
ResultVal<VAddr> FindFreeRegion(VAddr begin, VAddr end, u64 size) const;
/**
* Maps a memory-mapped IO region at a given address.
*