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Kernel: Enable global bit on kernel pages

This commit is contained in:
Bananymous 2023-07-13 15:08:54 +03:00
parent 7d00c2670f
commit 6c1ada8d0a
1 changed files with 19 additions and 3 deletions
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22
kernel/arch/x86_64/PageTable.cpp
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@ -17,6 +17,7 @@ namespace Kernel
static PageTable* s_kernel = nullptr;
static PageTable* s_current = nullptr;
static bool s_has_nxe = false;
static bool s_has_pge = false;
// Page Directories for kernel memory (KERNEL_OFFSET -> 0xFFFFFFFFFFFFFFFF)
static paddr_t s_global[(0xFFFFFFFFFFFFFFFF - KERNEL_OFFSET + 1) / (4096ull * 512ull * 512ull)] { };
@ -56,6 +57,18 @@ namespace Kernel
s_has_nxe = true;
}
uint32_t ecx, edx;
CPUID::get_features(ecx, edx);
if (edx & CPUID::EDX_PGE)
{
asm volatile(
"movq %cr4, %rax;"
"orq $0x80, %rax;"
"movq %rax, %cr4;"
);
s_has_pge = true;
}
ASSERT(s_kernel == nullptr);
s_kernel = new PageTable();
ASSERT(s_kernel);
@ -231,9 +244,12 @@ namespace Kernel
{
LockGuard _(m_lock);
uint64_t xd_bit = 0;
uint64_t extra_flags = 0;
if (s_has_nxe && !(flags & Flags::Execute))
xd_bit = 1ull << 63;
extra_flags |= 1ull << 63;
if (s_has_pge && this == s_kernel)
extra_flags |= 1ull << 8;
flags &= ~Flags::Execute;
if (vaddr && (vaddr >= KERNEL_OFFSET) != (this == s_kernel))
Kernel::panic("mapping {8H} to {8H}, kernel: {}", paddr, vaddr, this == s_kernel);
@ -276,7 +292,7 @@ namespace Kernel
}
uint64_t* pt = (uint64_t*)P2V(pd[pde] & PAGE_ADDR_MASK);
pt[pte] = xd_bit | paddr | flags;
pt[pte] = paddr | flags | extra_flags;
invalidate(canonicalize(vaddr));
}