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Kernel: VirtualRange doesn't store physical addresses of pages 

This was unnecessarry allocation, since the page table allready
contains virtual address -> physical address mappings.
This commit is contained in:
Bananymous 2023-09-24 01:29:34 +03:00
parent 2ef496a24a
commit 8b2bb95b81
2 changed files with 39 additions and 51 deletions
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1
kernel/include/kernel/Memory/VirtualRange.h
View File

@ -40,7 +40,6 @@ namespace Kernel
vaddr_t m_vaddr { 0 };
size_t m_size { 0 };
PageTable::flags_t m_flags { 0 };
BAN::Vector<paddr_t> m_physical_pages;
};
}

87
kernel/kernel/Memory/VirtualRange.cpp
View File

@ -1,4 +1,3 @@
#include <BAN/ScopeGuard.h>
#include <kernel/LockGuard.h>
#include <kernel/Memory/Heap.h>
#include <kernel/Memory/VirtualRange.h>
@ -21,27 +20,25 @@ namespace Kernel
result->m_vaddr = vaddr;
result->m_size = size;
result->m_flags = flags;
TRY(result->m_physical_pages.reserve(size / PAGE_SIZE));
ASSERT(page_table.reserve_range(vaddr, size));
BAN::ScopeGuard unmapper([vaddr, size, &page_table] { page_table.unmap_range(vaddr, size); });
TRY(result->m_physical_pages.reserve(size / PAGE_SIZE));
for (size_t offset = 0; offset < size; offset += PAGE_SIZE)
size_t needed_pages = size / PAGE_SIZE;
for (size_t i = 0; i < needed_pages; i++)
{
paddr_t paddr = Heap::get().take_free_page();
if (paddr == 0)
{
for (paddr_t release : result->m_physical_pages)
Heap::get().release_page(release);
for (size_t j = 0; j < i; j++)
Heap::get().release_page(page_table.physical_address_of(vaddr + j * PAGE_SIZE));
page_table.unmap_range(vaddr, size);
result->m_vaddr = 0;
return BAN::Error::from_errno(ENOMEM);
}
MUST(result->m_physical_pages.push_back(paddr));
page_table.map_page_at(paddr, vaddr + offset, flags);
page_table.map_page_at(paddr, vaddr + i * PAGE_SIZE, flags);
}
unmapper.disable();
return result;
}
@ -49,6 +46,7 @@ namespace Kernel
{
ASSERT(size % PAGE_SIZE == 0);
ASSERT(vaddr_start > 0);
ASSERT(vaddr_start + size <= vaddr_end);
// Align vaddr range to page boundaries
if (size_t rem = vaddr_start % PAGE_SIZE)
@ -64,37 +62,32 @@ namespace Kernel
auto result = BAN::UniqPtr<VirtualRange>::adopt(result_ptr);
result->m_kmalloc = false;
result->m_vaddr = 0;
result->m_size = size;
result->m_flags = flags;
TRY(result->m_physical_pages.reserve(size / PAGE_SIZE));
vaddr_t vaddr = page_table.reserve_free_contiguous_pages(size / PAGE_SIZE, vaddr_start, vaddr_end);
if (vaddr == 0)
return BAN::Error::from_errno(ENOMEM);
ASSERT(vaddr + size <= vaddr_end);
result->m_vaddr = vaddr;
BAN::ScopeGuard unmapper([vaddr, size, &page_table] { page_table.unmap_range(vaddr, size); });
if (vaddr + size > vaddr_end)
return BAN::Error::from_errno(ENOMEM);
size_t needed_pages = size / PAGE_SIZE;
result->m_vaddr = vaddr;
TRY(result->m_physical_pages.reserve(size / PAGE_SIZE));
for (size_t offset = 0; offset < size; offset += PAGE_SIZE)
for (size_t i = 0; i < needed_pages; i++)
{
paddr_t paddr = Heap::get().take_free_page();
if (paddr == 0)
{
for (paddr_t release : result->m_physical_pages)
Heap::get().release_page(release);
for (size_t j = 0; j < i; j++)
Heap::get().release_page(page_table.physical_address_of(vaddr + j * PAGE_SIZE));
page_table.unmap_range(vaddr, size);
result->m_vaddr = 0;
return BAN::Error::from_errno(ENOMEM);
}
MUST(result->m_physical_pages.push_back(paddr));
page_table.map_page_at(paddr, vaddr + offset, flags);
page_table.map_page_at(paddr, vaddr + i * PAGE_SIZE, flags);
}
unmapper.disable();
return result;
}
@ -122,33 +115,34 @@ namespace Kernel
VirtualRange::~VirtualRange()
{
if (m_kmalloc)
{
kfree((void*)m_vaddr);
if (m_vaddr == 0)
return;
}
if (m_kmalloc)
kfree((void*)m_vaddr);
else
{
for (size_t offset = 0; offset < size(); offset += PAGE_SIZE)
Heap::get().release_page(m_page_table.physical_address_of(vaddr() + offset));
m_page_table.unmap_range(vaddr(), size());
for (paddr_t page : m_physical_pages)
Heap::get().release_page(page);
}
}
BAN::ErrorOr<BAN::UniqPtr<VirtualRange>> VirtualRange::clone(PageTable& page_table)
{
ASSERT(&PageTable::current() == &m_page_table);
auto result = TRY(create_to_vaddr(page_table, vaddr(), size(), flags()));
m_page_table.lock();
LockGuard _(m_page_table);
ASSERT(m_page_table.is_page_free(0));
for (size_t i = 0; i < result->m_physical_pages.size(); i++)
for (size_t offset = 0; offset < size(); offset += PAGE_SIZE)
{
m_page_table.map_page_at(result->m_physical_pages[i], 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
memcpy((void*)0, (void*)(vaddr() + i * PAGE_SIZE), PAGE_SIZE);
m_page_table.map_page_at(result->m_page_table.physical_address_of(vaddr() + offset), 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
memcpy((void*)0, (void*)(vaddr() + offset), PAGE_SIZE);
}
m_page_table.unmap_page(0);
m_page_table.unlock();
return result;
}
@ -162,17 +156,14 @@ namespace Kernel
return;
}
page_table.lock();
LockGuard _(page_table);
ASSERT(page_table.is_page_free(0));
for (size_t i = 0; i < m_physical_pages.size(); i++)
for (size_t offset = 0; offset < size(); offset += PAGE_SIZE)
{
page_table.map_page_at(m_physical_pages[i], 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
page_table.map_page_at(m_page_table.physical_address_of(vaddr() + offset), 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
memset((void*)0, 0, PAGE_SIZE);
}
page_table.unmap_page(0);
page_table.unlock();
}
void VirtualRange::copy_from(size_t offset, const uint8_t* buffer, size_t bytes)
@ -193,14 +184,14 @@ namespace Kernel
return;
}
page_table.lock();
LockGuard _(page_table);
ASSERT(page_table.is_page_free(0));
size_t off = offset % PAGE_SIZE;
size_t i = offset / PAGE_SIZE;
// NOTE: we map the first page separately since it needs extra calculations
page_table.map_page_at(m_physical_pages[i], 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
page_table.map_page_at(m_page_table.physical_address_of(vaddr() + i * PAGE_SIZE), 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
memcpy((void*)off, buffer, PAGE_SIZE - off);
@ -212,7 +203,7 @@ namespace Kernel
{
size_t len = BAN::Math::min<size_t>(PAGE_SIZE, bytes);
page_table.map_page_at(m_physical_pages[i], 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
page_table.map_page_at(m_page_table.physical_address_of(vaddr() + i * PAGE_SIZE), 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
memcpy((void*)0, buffer, len);
@ -221,8 +212,6 @@ namespace Kernel
i++;
}
page_table.unmap_page(0);
page_table.unlock();
}
}