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/*
* Copyright (c) 2021, Patrick Meyer <git@the-space.agency>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <Kernel/Locking/Spinlock.h>
#include <Kernel/Memory/AnonymousVMObject.h>
namespace Kernel {
// Note: These need to be kept in sync with Userland/Libraries/LibC/sys/kcov.h
typedef volatile u64 kcov_pc_t;
#define KCOV_ENTRY_SIZE sizeof(kcov_pc_t)
#define KCOV_MAX_ENTRIES (10 * 1024 * 1024)
/*
* One KCOVInstance is allocated per process, when the process opens /dev/kcov
* for the first time. At this point it is in state OPENED. When a thread in
* the same process then uses the KCOV_ENABLE ioctl on the block device, the
* instance enters state TRACING.
*
* A KCOVInstance in state TRACING can return to state OPENED by either the
* KCOV_DISABLE ioctl or by killing the thread. A KCOVInstance in state OPENED
* can return to state UNUSED only when the process dies. At this point
* KCOVDevice::free_process will delete the KCOVInstance.
*/
class KCOVInstance final {
public:
explicit KCOVInstance(ProcessID pid);
ErrorOr<void> buffer_allocate(size_t buffer_size_in_entries);
bool has_buffer() const { return m_buffer != nullptr; }
void buffer_add_pc(u64 pc);
enum State {
UNUSED = 0,
OPENED = 1,
TRACING = 2,
} m_state { UNUSED };
State state() const { return m_state; }
void set_state(State state) { m_state = state; }
Memory::VMObject* vmobject() { return m_vmobject; }
Spinlock& spinlock() { return m_lock; }
private:
ProcessID m_pid { 0 };
u64 m_buffer_size_in_entries { 0 };
size_t m_buffer_size_in_bytes { 0 };
kcov_pc_t* m_buffer { nullptr };
LockRefPtr<Memory::AnonymousVMObject> m_vmobject;
// Here to ensure it's not garbage collected at the end of open()
OwnPtr<Memory::Region> m_kernel_region;
Spinlock m_lock { LockRank::None };
};
}
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