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Kernel: Set Cacheable parameter to NO explicitly in DMA helpers

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The cacheable parameter to allocate_kernel_region should be explicitly
set to No as this region is used to do physical memory transfers. Even
though most architectures ignore this even if it is set, it is better
to make this explicit.
This commit is contained in:
Pankaj Raghav 2022-01-08 13:07:30 +05:30 • committed by Andreas Kling
parent c5fb55725e
commit e79f94f998
1 changed files with 4 additions and 2 deletions
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6
Kernel/Memory/MemoryManager.cpp
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@ -748,7 +748,8 @@ ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_page(S
dma_buffer_page = allocate_supervisor_physical_page();
if (dma_buffer_page.is_null())
return ENOMEM;
auto region_or_error = allocate_kernel_region(dma_buffer_page->paddr(), PAGE_SIZE, name, access);
// Do not enable Cache for this region as physical memory transfers are performed (Most architectures have this behaviour by default)
auto region_or_error = allocate_kernel_region(dma_buffer_page->paddr(), PAGE_SIZE, name, access, Region::Cacheable::No);
return region_or_error;
}
@ -758,7 +759,8 @@ ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_pages(
dma_buffer_pages = allocate_contiguous_supervisor_physical_pages(size);
if (dma_buffer_pages.is_empty())
return ENOMEM;
auto region_or_error = allocate_kernel_region(dma_buffer_pages.first().paddr(), size, name, access);
// Do not enable Cache for this region as physical memory transfers are performed (Most architectures have this behaviour by default)
auto region_or_error = allocate_kernel_region(dma_buffer_pages.first().paddr(), size, name, access, Region::Cacheable::No);
return region_or_error;
}