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/*
* Copyright (c) 2021, Patrick Meyer <git@the-space.agency>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Devices/KCOVInstance.h>
namespace Kernel {
KCOVInstance::KCOVInstance(ProcessID pid)
{
m_pid = pid;
}
ErrorOr<void> KCOVInstance::buffer_allocate(size_t buffer_size_in_entries)
{
if (buffer_size_in_entries < 2 || buffer_size_in_entries > KCOV_MAX_ENTRIES)
return EINVAL;
// first entry contains index of last PC
m_buffer_size_in_entries = buffer_size_in_entries - 1;
m_buffer_size_in_bytes = TRY(Memory::page_round_up(buffer_size_in_entries * KCOV_ENTRY_SIZE));
// one single vmobject is representing the buffer
// - we allocate one kernel region using that vmobject
// - when an mmap call comes in, we allocate another userspace region,
// backed by the same vmobject
m_vmobject = TRY(Memory::AnonymousVMObject::try_create_with_size(m_buffer_size_in_bytes, AllocationStrategy::AllocateNow));
auto region_name = TRY(KString::formatted("kcov_{}", m_pid));
m_kernel_region = TRY(MM.allocate_kernel_region_with_vmobject(
*m_vmobject, m_buffer_size_in_bytes, region_name->view(),
Memory::Region::Access::ReadWrite));
m_buffer = (u64*)m_kernel_region->vaddr().as_ptr();
return {};
}
void KCOVInstance::buffer_add_pc(u64 pc)
{
auto idx = (u64)m_buffer[0];
if (idx >= m_buffer_size_in_entries) {
// the buffer is already full
return;
}
m_buffer[idx + 1] = pc;
m_buffer[0] = idx + 1;
}
}
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