ladybird/Kernel/PerformanceEventBuffer.cpp
Andreas Kling 2617adac52 Kernel: Store AddressSpace memory regions in an IntrusiveRedBlackTree
This means we never need to allocate when inserting/removing regions
from the address space.
2022-04-03 21:51:58 +02:00

384 lines
15 KiB
C++

/*
* Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/JsonArraySerializer.h>
#include <AK/JsonObjectSerializer.h>
#include <AK/ScopeGuard.h>
#include <Kernel/Arch/RegisterState.h>
#include <Kernel/Arch/SmapDisabler.h>
#include <Kernel/Arch/x86/SafeMem.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/KBufferBuilder.h>
#include <Kernel/PerformanceEventBuffer.h>
#include <Kernel/Process.h>
namespace Kernel {
PerformanceEventBuffer::PerformanceEventBuffer(NonnullOwnPtr<KBuffer> buffer)
: m_buffer(move(buffer))
{
}
NEVER_INLINE ErrorOr<void> PerformanceEventBuffer::append(int type, FlatPtr arg1, FlatPtr arg2, StringView arg3, Thread* current_thread, FlatPtr arg4, u64 arg5, ErrorOr<FlatPtr> arg6)
{
FlatPtr base_pointer;
#if ARCH(I386)
asm volatile("movl %%ebp, %%eax"
: "=a"(base_pointer));
#else
asm volatile("movq %%rbp, %%rax"
: "=a"(base_pointer));
#endif
return append_with_ip_and_bp(current_thread->pid(), current_thread->tid(), 0, base_pointer, type, 0, arg1, arg2, arg3, arg4, arg5, arg6);
}
static Vector<FlatPtr, PerformanceEvent::max_stack_frame_count> raw_backtrace(FlatPtr bp, FlatPtr ip)
{
Vector<FlatPtr, PerformanceEvent::max_stack_frame_count> backtrace;
if (ip != 0)
backtrace.unchecked_append(ip);
FlatPtr stack_ptr_copy;
FlatPtr stack_ptr = bp;
// FIXME: Figure out how to remove this SmapDisabler without breaking profile stacks.
SmapDisabler disabler;
// NOTE: The stack should always have kernel frames first, followed by userspace frames.
// If a userspace frame points back into kernel memory, something is afoot.
bool is_walking_userspace_stack = false;
while (stack_ptr) {
void* fault_at;
if (!safe_memcpy(&stack_ptr_copy, (void*)stack_ptr, sizeof(FlatPtr), fault_at))
break;
if (!Memory::is_user_address(VirtualAddress { stack_ptr })) {
if (is_walking_userspace_stack) {
dbgln("SHENANIGANS! Userspace stack points back into kernel memory");
break;
}
} else {
is_walking_userspace_stack = true;
}
FlatPtr retaddr;
if (!safe_memcpy(&retaddr, (void*)(stack_ptr + sizeof(FlatPtr)), sizeof(FlatPtr), fault_at))
break;
if (retaddr == 0)
break;
backtrace.unchecked_append(retaddr);
if (backtrace.size() == PerformanceEvent::max_stack_frame_count)
break;
stack_ptr = stack_ptr_copy;
}
return backtrace;
}
ErrorOr<void> PerformanceEventBuffer::append_with_ip_and_bp(ProcessID pid, ThreadID tid, RegisterState const& regs,
int type, u32 lost_samples, FlatPtr arg1, FlatPtr arg2, StringView arg3, FlatPtr arg4, u64 arg5, ErrorOr<FlatPtr> arg6)
{
return append_with_ip_and_bp(pid, tid, regs.ip(), regs.bp(), type, lost_samples, arg1, arg2, arg3, arg4, arg5, arg6);
}
ErrorOr<void> PerformanceEventBuffer::append_with_ip_and_bp(ProcessID pid, ThreadID tid,
FlatPtr ip, FlatPtr bp, int type, u32 lost_samples, FlatPtr arg1, FlatPtr arg2, StringView arg3, FlatPtr arg4, u64 arg5, ErrorOr<FlatPtr> arg6)
{
if (count() >= capacity())
return ENOBUFS;
if ((g_profiling_event_mask & type) == 0)
return EINVAL;
auto* current_thread = Thread::current();
u32 enter_count = 0;
if (current_thread)
enter_count = current_thread->enter_profiler();
ScopeGuard leave_profiler([&] {
if (current_thread)
current_thread->leave_profiler();
});
if (enter_count > 0)
return EINVAL;
PerformanceEvent event;
event.type = type;
event.lost_samples = lost_samples;
switch (type) {
case PERF_EVENT_SAMPLE:
break;
case PERF_EVENT_MALLOC:
event.data.malloc.size = arg1;
event.data.malloc.ptr = arg2;
break;
case PERF_EVENT_FREE:
event.data.free.ptr = arg1;
break;
case PERF_EVENT_MMAP:
event.data.mmap.ptr = arg1;
event.data.mmap.size = arg2;
memset(event.data.mmap.name, 0, sizeof(event.data.mmap.name));
if (!arg3.is_empty())
memcpy(event.data.mmap.name, arg3.characters_without_null_termination(), min(arg3.length(), sizeof(event.data.mmap.name) - 1));
break;
case PERF_EVENT_MUNMAP:
event.data.munmap.ptr = arg1;
event.data.munmap.size = arg2;
break;
case PERF_EVENT_PROCESS_CREATE:
event.data.process_create.parent_pid = arg1;
memset(event.data.process_create.executable, 0, sizeof(event.data.process_create.executable));
if (!arg3.is_empty()) {
memcpy(event.data.process_create.executable, arg3.characters_without_null_termination(),
min(arg3.length(), sizeof(event.data.process_create.executable) - 1));
}
break;
case PERF_EVENT_PROCESS_EXEC:
memset(event.data.process_exec.executable, 0, sizeof(event.data.process_exec.executable));
if (!arg3.is_empty()) {
memcpy(event.data.process_exec.executable, arg3.characters_without_null_termination(),
min(arg3.length(), sizeof(event.data.process_exec.executable) - 1));
}
break;
case PERF_EVENT_PROCESS_EXIT:
break;
case PERF_EVENT_THREAD_CREATE:
event.data.thread_create.parent_tid = arg1;
break;
case PERF_EVENT_THREAD_EXIT:
break;
case PERF_EVENT_CONTEXT_SWITCH:
event.data.context_switch.next_pid = arg1;
event.data.context_switch.next_tid = arg2;
break;
case PERF_EVENT_KMALLOC:
event.data.kmalloc.size = arg1;
event.data.kmalloc.ptr = arg2;
break;
case PERF_EVENT_KFREE:
event.data.kfree.size = arg1;
event.data.kfree.ptr = arg2;
break;
case PERF_EVENT_PAGE_FAULT:
break;
case PERF_EVENT_SYSCALL:
break;
case PERF_EVENT_SIGNPOST:
event.data.signpost.arg1 = arg1;
event.data.signpost.arg2 = arg2;
break;
case PERF_EVENT_READ:
event.data.read.fd = arg1;
event.data.read.size = arg2;
event.data.read.filename_index = arg4;
event.data.read.start_timestamp = arg5;
event.data.read.success = !arg6.is_error();
break;
default:
return EINVAL;
}
auto backtrace = raw_backtrace(bp, ip);
event.stack_size = min(sizeof(event.stack) / sizeof(FlatPtr), static_cast<size_t>(backtrace.size()));
memcpy(event.stack, backtrace.data(), event.stack_size * sizeof(FlatPtr));
event.pid = pid.value();
event.tid = tid.value();
event.timestamp = TimeManagement::the().uptime_ms();
at(m_count++) = event;
return {};
}
PerformanceEvent& PerformanceEventBuffer::at(size_t index)
{
VERIFY(index < capacity());
auto* events = reinterpret_cast<PerformanceEvent*>(m_buffer->data());
return events[index];
}
template<typename Serializer>
ErrorOr<void> PerformanceEventBuffer::to_json_impl(Serializer& object) const
{
{
auto strings = TRY(object.add_array("strings"));
Vector<KString*> strings_sorted_by_index;
TRY(strings_sorted_by_index.try_resize(m_strings.size()));
for (auto& entry : m_strings) {
strings_sorted_by_index[entry.value] = const_cast<Kernel::KString*>(entry.key.ptr());
}
for (size_t i = 0; i < m_strings.size(); i++) {
TRY(strings.add(strings_sorted_by_index[i]->view()));
}
TRY(strings.finish());
}
bool show_kernel_addresses = Process::current().is_superuser();
auto array = TRY(object.add_array("events"));
bool seen_first_sample = false;
for (size_t i = 0; i < m_count; ++i) {
auto const& event = at(i);
if (!show_kernel_addresses) {
if (event.type == PERF_EVENT_KMALLOC || event.type == PERF_EVENT_KFREE)
continue;
}
auto event_object = TRY(array.add_object());
switch (event.type) {
case PERF_EVENT_SAMPLE:
TRY(event_object.add("type", "sample"));
break;
case PERF_EVENT_MALLOC:
TRY(event_object.add("type", "malloc"));
TRY(event_object.add("ptr", static_cast<u64>(event.data.malloc.ptr)));
TRY(event_object.add("size", static_cast<u64>(event.data.malloc.size)));
break;
case PERF_EVENT_FREE:
TRY(event_object.add("type", "free"));
TRY(event_object.add("ptr", static_cast<u64>(event.data.free.ptr)));
break;
case PERF_EVENT_MMAP:
TRY(event_object.add("type", "mmap"));
TRY(event_object.add("ptr", static_cast<u64>(event.data.mmap.ptr)));
TRY(event_object.add("size", static_cast<u64>(event.data.mmap.size)));
TRY(event_object.add("name", event.data.mmap.name));
break;
case PERF_EVENT_MUNMAP:
TRY(event_object.add("type", "munmap"));
TRY(event_object.add("ptr", static_cast<u64>(event.data.munmap.ptr)));
TRY(event_object.add("size", static_cast<u64>(event.data.munmap.size)));
break;
case PERF_EVENT_PROCESS_CREATE:
TRY(event_object.add("type", "process_create"));
TRY(event_object.add("parent_pid", static_cast<u64>(event.data.process_create.parent_pid)));
TRY(event_object.add("executable", event.data.process_create.executable));
break;
case PERF_EVENT_PROCESS_EXEC:
TRY(event_object.add("type", "process_exec"));
TRY(event_object.add("executable", event.data.process_exec.executable));
break;
case PERF_EVENT_PROCESS_EXIT:
TRY(event_object.add("type", "process_exit"));
break;
case PERF_EVENT_THREAD_CREATE:
TRY(event_object.add("type", "thread_create"));
TRY(event_object.add("parent_tid", static_cast<u64>(event.data.thread_create.parent_tid)));
break;
case PERF_EVENT_THREAD_EXIT:
TRY(event_object.add("type", "thread_exit"));
break;
case PERF_EVENT_CONTEXT_SWITCH:
TRY(event_object.add("type", "context_switch"));
TRY(event_object.add("next_pid", static_cast<u64>(event.data.context_switch.next_pid)));
TRY(event_object.add("next_tid", static_cast<u64>(event.data.context_switch.next_tid)));
break;
case PERF_EVENT_KMALLOC:
TRY(event_object.add("type", "kmalloc"));
TRY(event_object.add("ptr", static_cast<u64>(event.data.kmalloc.ptr)));
TRY(event_object.add("size", static_cast<u64>(event.data.kmalloc.size)));
break;
case PERF_EVENT_KFREE:
TRY(event_object.add("type", "kfree"));
TRY(event_object.add("ptr", static_cast<u64>(event.data.kfree.ptr)));
TRY(event_object.add("size", static_cast<u64>(event.data.kfree.size)));
break;
case PERF_EVENT_PAGE_FAULT:
TRY(event_object.add("type", "page_fault"));
break;
case PERF_EVENT_SYSCALL:
TRY(event_object.add("type", "syscall"));
break;
case PERF_EVENT_SIGNPOST:
TRY(event_object.add("type"sv, "signpost"sv));
TRY(event_object.add("arg1"sv, event.data.signpost.arg1));
TRY(event_object.add("arg2"sv, event.data.signpost.arg2));
break;
case PERF_EVENT_READ:
TRY(event_object.add("type", "read"));
TRY(event_object.add("fd", event.data.read.fd));
TRY(event_object.add("size"sv, event.data.read.size));
TRY(event_object.add("filename_index"sv, event.data.read.filename_index));
TRY(event_object.add("start_timestamp"sv, event.data.read.start_timestamp));
TRY(event_object.add("success"sv, event.data.read.success));
break;
}
TRY(event_object.add("pid", event.pid));
TRY(event_object.add("tid", event.tid));
TRY(event_object.add("timestamp", event.timestamp));
TRY(event_object.add("lost_samples", seen_first_sample ? event.lost_samples : 0));
if (event.type == PERF_EVENT_SAMPLE)
seen_first_sample = true;
auto stack_array = TRY(event_object.add_array("stack"));
for (size_t j = 0; j < event.stack_size; ++j) {
auto address = event.stack[j];
if (!show_kernel_addresses && !Memory::is_user_address(VirtualAddress { address }))
address = 0xdeadc0de;
TRY(stack_array.add(address));
}
TRY(stack_array.finish());
TRY(event_object.finish());
}
TRY(array.finish());
TRY(object.finish());
return {};
}
ErrorOr<void> PerformanceEventBuffer::to_json(KBufferBuilder& builder) const
{
auto object = TRY(JsonObjectSerializer<>::try_create(builder));
return to_json_impl(object);
}
OwnPtr<PerformanceEventBuffer> PerformanceEventBuffer::try_create_with_size(size_t buffer_size)
{
auto buffer_or_error = KBuffer::try_create_with_size(buffer_size, Memory::Region::Access::ReadWrite, "Performance events", AllocationStrategy::AllocateNow);
if (buffer_or_error.is_error())
return {};
return adopt_own_if_nonnull(new (nothrow) PerformanceEventBuffer(buffer_or_error.release_value()));
}
ErrorOr<void> PerformanceEventBuffer::add_process(Process const& process, ProcessEventType event_type)
{
SpinlockLocker locker(process.address_space().get_lock());
OwnPtr<KString> executable;
if (process.executable())
executable = TRY(process.executable()->try_serialize_absolute_path());
else
executable = TRY(KString::formatted("<{}>", process.name()));
TRY(append_with_ip_and_bp(process.pid(), 0, 0, 0,
event_type == ProcessEventType::Create ? PERF_EVENT_PROCESS_CREATE : PERF_EVENT_PROCESS_EXEC,
0, process.pid().value(), 0, executable->view()));
ErrorOr<void> result;
process.for_each_thread([&](auto& thread) {
result = append_with_ip_and_bp(process.pid(), thread.tid().value(),
0, 0, PERF_EVENT_THREAD_CREATE, 0, 0, 0, nullptr);
return result.is_error() ? IterationDecision::Break : IterationDecision::Continue;
});
TRY(result);
for (auto const& region : process.address_space().regions()) {
TRY(append_with_ip_and_bp(process.pid(), 0,
0, 0, PERF_EVENT_MMAP, 0, region.range().base().get(), region.range().size(), region.name()));
}
return {};
}
ErrorOr<FlatPtr> PerformanceEventBuffer::register_string(NonnullOwnPtr<KString> string)
{
auto it = m_strings.find(string);
if (it != m_strings.end()) {
return it->value;
}
auto new_index = m_strings.size();
TRY(m_strings.try_set(move(string), move(new_index)));
return new_index;
}
}