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Kernel: Implement WriteCombining memory

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This makes framebuffer much faster on real hardware
This commit is contained in:
Bananymous
2024-07-15 22:08:20 +03:00
parent 42c3fa24f0
commit 0578d41500
8 changed files with 64 additions and 20 deletions
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24
kernel/arch/x86_64/PageTable.cpp
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@@ -56,8 +56,6 @@ namespace Kernel
result |= Flags::Execute;
if (entry & Flags::Reserved)
result |= Flags::Reserved;
if (entry & Flags::CacheDisable)
result |= Flags::CacheDisable;
if (entry & Flags::UserSupervisor)
result |= Flags::UserSupervisor;
if (entry & Flags::ReadWrite)
@@ -106,6 +104,15 @@ namespace Kernel
);
}
// 64-bit always has PAT, set PAT4 = WC, PAT5 = WT
asm volatile(
"movl $0x277, %%ecx;"
"rdmsr;"
"movw $0x0401, %%dx;"
"wrmsr;"
::: "eax", "ecx", "edx", "memory"
);
// enable write protect
asm volatile(
"movq %%cr0, %%rax;"
@@ -367,7 +374,7 @@ namespace Kernel
unmap_page(page * PAGE_SIZE);
}
void PageTable::map_page_at(paddr_t paddr, vaddr_t vaddr, flags_t flags)
void PageTable::map_page_at(paddr_t paddr, vaddr_t vaddr, flags_t flags, MemoryType memory_type)
{
ASSERT(vaddr);
ASSERT(vaddr != fast_page());
@@ -393,8 +400,11 @@ namespace Kernel
extra_flags |= 1ull << 63;
if (flags & Flags::Reserved)
extra_flags |= Flags::Reserved;
if (flags & Flags::CacheDisable)
extra_flags |= Flags::CacheDisable;
if (memory_type == MemoryType::WriteCombining)
extra_flags |= (1ull << 7);
if (memory_type == MemoryType::WriteThrough)
extra_flags |= (1ull << 7) | (1ull << 3);
// NOTE: we add present here, since it has to be available in higher level structures
flags_t uwr_flags = (flags & (Flags::UserSupervisor | Flags::ReadWrite)) | Flags::Present;
@@ -434,7 +444,7 @@ namespace Kernel
invalidate(vaddr);
}
void PageTable::map_range_at(paddr_t paddr, vaddr_t vaddr, size_t size, flags_t flags)
void PageTable::map_range_at(paddr_t paddr, vaddr_t vaddr, size_t size, flags_t flags, MemoryType memory_type)
{
ASSERT(is_canonical(vaddr));
@@ -446,7 +456,7 @@ namespace Kernel
SpinLockGuard _(m_lock);
for (size_t page = 0; page < page_count; page++)
map_page_at(paddr + page * PAGE_SIZE, vaddr + page * PAGE_SIZE, flags);
map_page_at(paddr + page * PAGE_SIZE, vaddr + page * PAGE_SIZE, flags, memory_type);
}
uint64_t PageTable::get_page_data(vaddr_t vaddr) const