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/*
* Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/JsonArraySerializer.h>
#include <AK/JsonObject.h>
#include <AK/JsonObjectSerializer.h>
#include <Kernel/Arch/x86/SmapDisabler.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))
{
}
KResult PerformanceEventBuffer::append(int type, FlatPtr arg1, FlatPtr arg2)
{
FlatPtr ebp;
asm volatile("movl %%ebp, %%eax"
: "=a"(ebp));
auto current_thread = Thread::current();
auto eip = current_thread->get_register_dump_from_stack().eip;
return append_with_eip_and_ebp(eip, ebp, type, arg1, arg2);
}
static Vector<FlatPtr, PerformanceEvent::max_stack_frame_count> raw_backtrace(FlatPtr ebp, FlatPtr eip)
{
Vector<FlatPtr, PerformanceEvent::max_stack_frame_count> backtrace;
backtrace.append(eip);
FlatPtr stack_ptr_copy;
FlatPtr stack_ptr = (FlatPtr)ebp;
// FIXME: Figure out how to remove this SmapDisabler without breaking profile stacks.
SmapDisabler disabler;
while (stack_ptr) {
void* fault_at;
if (!safe_memcpy(&stack_ptr_copy, (void*)stack_ptr, sizeof(FlatPtr), fault_at))
break;
FlatPtr retaddr;
if (!safe_memcpy(&retaddr, (void*)(stack_ptr + sizeof(FlatPtr)), sizeof(FlatPtr), fault_at))
break;
backtrace.append(retaddr);
if (backtrace.size() == PerformanceEvent::max_stack_frame_count)
break;
stack_ptr = stack_ptr_copy;
}
return backtrace;
}
KResult PerformanceEventBuffer::append_with_eip_and_ebp(u32 eip, u32 ebp, int type, FlatPtr arg1, FlatPtr arg2)
{
if (count() >= capacity())
return ENOBUFS;
PerformanceEvent event;
event.type = type;
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;
default:
return EINVAL;
}
auto backtrace = raw_backtrace(ebp, eip);
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.tid = Thread::current()->tid().value();
event.timestamp = TimeManagement::the().uptime_ms();
at(m_count++) = event;
return KSuccess;
}
PerformanceEvent& PerformanceEventBuffer::at(size_t index)
{
VERIFY(index < capacity());
auto* events = reinterpret_cast<PerformanceEvent*>(m_buffer->data());
return events[index];
}
template<typename Serializer>
bool PerformanceEventBuffer::to_json_impl(Serializer& object) const
{
auto array = object.add_array("events");
for (size_t i = 0; i < m_count; ++i) {
auto& event = at(i);
auto event_object = array.add_object();
switch (event.type) {
case PERF_EVENT_SAMPLE:
event_object.add("type", "sample");
break;
case PERF_EVENT_MALLOC:
event_object.add("type", "malloc");
event_object.add("ptr", static_cast<u64>(event.data.malloc.ptr));
event_object.add("size", static_cast<u64>(event.data.malloc.size));
break;
case PERF_EVENT_FREE:
event_object.add("type", "free");
event_object.add("ptr", static_cast<u64>(event.data.free.ptr));
break;
}
event_object.add("tid", event.tid);
event_object.add("timestamp", event.timestamp);
auto stack_array = event_object.add_array("stack");
for (size_t j = 0; j < event.stack_size; ++j) {
stack_array.add(event.stack[j]);
}
stack_array.finish();
event_object.finish();
}
array.finish();
object.finish();
return true;
}
bool PerformanceEventBuffer::to_json(KBufferBuilder& builder) const
{
JsonObjectSerializer object(builder);
auto processes_array = object.add_array("processes");
for (auto& it : m_processes) {
auto& process = *it.value;
auto process_object = processes_array.add_object();
process_object.add("pid", process.pid.value());
process_object.add("executable", process.executable);
auto regions_array = process_object.add_array("regions");
for (auto& region : process.regions) {
auto region_object = regions_array.add_object();
region_object.add("name", region.name);
region_object.add("base", region.range.base().get());
region_object.add("size", region.range.size());
}
}
processes_array.finish();
return to_json_impl(object);
}
OwnPtr<PerformanceEventBuffer> PerformanceEventBuffer::try_create_with_size(size_t buffer_size)
{
auto buffer = KBuffer::try_create_with_size(buffer_size, Region::Access::Read | Region::Access::Write, "Performance events", AllocationStrategy::AllocateNow);
if (!buffer)
return {};
return adopt_own(*new PerformanceEventBuffer(buffer.release_nonnull()));
}
void PerformanceEventBuffer::add_process(const Process& process)
{
// FIXME: What about threads that have died?
ScopedSpinLock locker(process.space().get_lock());
String executable;
if (process.executable())
executable = process.executable()->absolute_path();
auto sampled_process = adopt_own(*new SampledProcess {
.pid = process.pid().value(),
.executable = executable,
.threads = {},
.regions = {},
});
process.for_each_thread([&](auto& thread) {
sampled_process->threads.set(thread.tid());
return IterationDecision::Continue;
});
for (auto& region : process.space().regions()) {
sampled_process->regions.append(SampledProcess::Region {
.name = region->name(),
.range = region->range(),
});
}
m_processes.set(process.pid(), move(sampled_process));
}
}
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