1 files changed, 155 insertions, 0 deletions
diff --git a/Kernel/Tasks/PerformanceEventBuffer.h b/Kernel/Tasks/PerformanceEventBuffer.h
new file mode 100644
index 0000000000..74233424be
--- /dev/null
+++ b/Kernel/Tasks/PerformanceEventBuffer.h
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <Kernel/Library/KBuffer.h>
+
+namespace Kernel {
+
+class KBufferBuilder;
+struct RegisterState;
+
+struct [[gnu::packed]] MallocPerformanceEvent {
+    size_t size;
+    FlatPtr ptr;
+};
+
+struct [[gnu::packed]] FreePerformanceEvent {
+    size_t size;
+    FlatPtr ptr;
+};
+
+struct [[gnu::packed]] MmapPerformanceEvent {
+    size_t size;
+    FlatPtr ptr;
+    char name[64];
+};
+
+struct [[gnu::packed]] MunmapPerformanceEvent {
+    size_t size;
+    FlatPtr ptr;
+};
+
+struct [[gnu::packed]] ProcessCreatePerformanceEvent {
+    pid_t parent_pid;
+    char executable[64];
+};
+
+struct [[gnu::packed]] ProcessExecPerformanceEvent {
+    char executable[64];
+};
+
+struct [[gnu::packed]] ThreadCreatePerformanceEvent {
+    pid_t parent_tid;
+};
+
+struct [[gnu::packed]] ContextSwitchPerformanceEvent {
+    pid_t next_pid;
+    u32 next_tid;
+};
+
+struct [[gnu::packed]] KMallocPerformanceEvent {
+    size_t size;
+    FlatPtr ptr;
+};
+
+struct [[gnu::packed]] KFreePerformanceEvent {
+    size_t size;
+    FlatPtr ptr;
+};
+
+struct [[gnu::packed]] SignpostPerformanceEvent {
+    FlatPtr arg1;
+    FlatPtr arg2;
+};
+
+struct [[gnu::packed]] ReadPerformanceEvent {
+    int fd;
+    size_t size;
+    size_t filename_index;
+    size_t start_timestamp;
+    bool success;
+};
+
+struct [[gnu::packed]] PerformanceEvent {
+    u32 type { 0 };
+    u8 stack_size { 0 };
+    u32 pid { 0 };
+    u32 tid { 0 };
+    u64 timestamp;
+    u32 lost_samples;
+    union {
+        MallocPerformanceEvent malloc;
+        FreePerformanceEvent free;
+        MmapPerformanceEvent mmap;
+        MunmapPerformanceEvent munmap;
+        ProcessCreatePerformanceEvent process_create;
+        ProcessExecPerformanceEvent process_exec;
+        ThreadCreatePerformanceEvent thread_create;
+        ContextSwitchPerformanceEvent context_switch;
+        KMallocPerformanceEvent kmalloc;
+        KFreePerformanceEvent kfree;
+        SignpostPerformanceEvent signpost;
+        ReadPerformanceEvent read;
+    } data;
+    static constexpr size_t max_stack_frame_count = 64;
+    FlatPtr stack[max_stack_frame_count];
+};
+
+enum class ProcessEventType {
+    Create,
+    Exec
+};
+
+class PerformanceEventBuffer {
+public:
+    static OwnPtr<PerformanceEventBuffer> try_create_with_size(size_t buffer_size);
+
+    ErrorOr<void> append(int type, FlatPtr arg1, FlatPtr arg2, StringView arg3, Thread* current_thread = Thread::current(), FlatPtr arg4 = 0, u64 arg5 = 0, ErrorOr<FlatPtr> const& arg6 = 0);
+    ErrorOr<void> append_with_ip_and_bp(ProcessID pid, ThreadID tid, FlatPtr eip, FlatPtr ebp,
+        int type, u32 lost_samples, FlatPtr arg1, FlatPtr arg2, StringView arg3, FlatPtr arg4 = 0, u64 arg5 = {}, ErrorOr<FlatPtr> const& arg6 = 0);
+    ErrorOr<void> 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 = 0, u64 arg5 = {}, ErrorOr<FlatPtr> const& arg6 = 0);
+
+    void clear()
+    {
+        m_count = 0;
+    }
+
+    size_t capacity() const { return m_buffer->size() / sizeof(PerformanceEvent); }
+    size_t count() const { return m_count; }
+    PerformanceEvent const& at(size_t index) const
+    {
+        return const_cast<PerformanceEventBuffer&>(*this).at(index);
+    }
+
+    ErrorOr<void> to_json(KBufferBuilder&) const;
+
+    ErrorOr<void> add_process(Process const&, ProcessEventType event_type);
+
+    ErrorOr<FlatPtr> register_string(NonnullOwnPtr<KString>);
+
+private:
+    explicit PerformanceEventBuffer(NonnullOwnPtr<KBuffer>);
+
+    template<typename Serializer>
+    ErrorOr<void> to_json_impl(Serializer&) const;
+
+    PerformanceEvent& at(size_t index);
+
+    size_t m_count { 0 };
+    NonnullOwnPtr<KBuffer> m_buffer;
+
+    HashMap<NonnullOwnPtr<KString>, size_t> m_strings;
+};
+
+extern bool g_profiling_all_threads;
+extern PerformanceEventBuffer* g_global_perf_events;
+extern u64 g_profiling_event_mask;
+
+}