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Kernel: fix some math in physical ranges 

I allocated 1 bitmap page per 8 data pages. Bitmap page can actually
store 8*PAGE_SIZE data pages.

Also properly set last bits in bitmap. I did not care about endianness
but now we set the bits on unsigned long longs instead of bytes.
This commit is contained in:
Bananymous 2023-10-08 13:25:34 +03:00
parent a6ca9fd453
commit 2aabf43ace
1 changed files with 11 additions and 4 deletions
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15
kernel/kernel/Memory/PhysicalRange.cpp
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@ -13,7 +13,7 @@ namespace Kernel
PhysicalRange::PhysicalRange(paddr_t paddr, size_t size)
: m_paddr(paddr)
, m_size(size)
, m_bitmap_pages(BAN::Math::div_round_up<size_t>(size / PAGE_SIZE, 8))
, m_bitmap_pages(BAN::Math::div_round_up<size_t>(size / PAGE_SIZE, PAGE_SIZE * 8))
, m_data_pages((size / PAGE_SIZE) - m_bitmap_pages)
, m_free_pages(m_data_pages)
{
@ -26,9 +26,16 @@ namespace Kernel
PageTable::kernel().map_range_at(m_paddr, m_vaddr, size, PageTable::Flags::ReadWrite | PageTable::Flags::Present);
memset((void*)m_vaddr, 0x00, m_bitmap_pages * PAGE_SIZE);
memset((void*)m_vaddr, 0xFF, m_data_pages / 8);
for (ull i = 0; i < m_data_pages % 8; i++)
((uint8_t*)m_vaddr)[m_data_pages / 8] |= 1 << i;
for (ull i = 0; i < m_data_pages / ull_bits; i++)
ull_bitmap_ptr()[i] = ~0ull;
if (m_data_pages % ull_bits)
{
ull off = m_data_pages / ull_bits;
ull bits = m_data_pages % ull_bits;
ull_bitmap_ptr()[off] = ~(~0ull << bits);
}
dprintln("physical range needs {} pages for bitmap", m_bitmap_pages);
}