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Kernel: Temporarily force FileBackedRegion mappings writable 

Now that write-protect bit is enabled this is neccessary.
This commit is contained in:
Bananymous 2023-10-30 19:08:33 +02:00
parent 3bac19e518
commit a44482639d
1 changed files with 7 additions and 1 deletions
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8
kernel/kernel/Memory/FileBackedRegion.cpp
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@ -98,7 +98,9 @@ namespace Kernel
paddr_t paddr = Heap::get().take_free_page(); paddr_t paddr = Heap::get().take_free_page();
if (paddr == 0) if (paddr == 0)
return BAN::Error::from_errno(ENOMEM); return BAN::Error::from_errno(ENOMEM);
m_page_table.map_page_at(paddr, vaddr, m_flags);
// Temporarily force mapping to be writable so kernel can write to it
m_page_table.map_page_at(paddr, vaddr, m_flags | PageTable::Flags::ReadWrite);
size_t file_offset = m_offset + (vaddr - m_vaddr); size_t file_offset = m_offset + (vaddr - m_vaddr);
size_t bytes = BAN::Math::min<size_t>(m_size - file_offset, PAGE_SIZE); size_t bytes = BAN::Math::min<size_t>(m_size - file_offset, PAGE_SIZE);
@ -120,6 +122,10 @@ namespace Kernel
m_page_table.unmap_page(vaddr); m_page_table.unmap_page(vaddr);
return BAN::Error::from_errno(EIO); return BAN::Error::from_errno(EIO);
} }
// Disable writable if not wanted
if (!(m_flags & PageTable::Flags::ReadWrite))
m_page_table.map_page_at(paddr, vaddr, m_flags);
} }
else if (m_type == Type::SHARED) else if (m_type == Type::SHARED)
{ {