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Kernel: Use ksyms in-place instead of duplicating them into eternal heap

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We can leave the .ksyms section mapped-but-read-only and then have the
symbols index simply point into it.

Note that we manually insert null-terminators into the symbols section
while parsing it.

This gets rid of ~950 KiB of kmalloc_eternal() at startup. :^)
This commit is contained in:
Andreas Kling 2021-12-17 09:52:06 +01:00
parent abf2204402
commit 1f2d0d0ad4
4 changed files with 11 additions and 13 deletions
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7
Kernel/Memory/MemoryManager.cpp
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@ -136,7 +136,7 @@ void MemoryManager::unmap_text_after_init()
dmesgln("Unmapped {} KiB of kernel text after init! :^)", (end - start) / KiB);
}
void MemoryManager::unmap_ksyms_after_init()
void MemoryManager::protect_ksyms_after_init()
{
SpinlockLocker mm_lock(s_mm_lock);
SpinlockLocker page_lock(kernel_page_directory().get_lock());
@ -144,14 +144,13 @@ void MemoryManager::unmap_ksyms_after_init()
auto start = page_round_down((FlatPtr)start_of_kernel_ksyms);
auto end = page_round_up((FlatPtr)end_of_kernel_ksyms);
// Unmap the entire .ksyms section
for (auto i = start; i < end; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
pte.clear();
pte.set_writable(false);
flush_tlb(&kernel_page_directory(), VirtualAddress(i));
}
dmesgln("Unmapped {} KiB of kernel symbols after init! :^)", (end - start) / KiB);
dmesgln("Write-protected kernel symbols after init.");
}
UNMAP_AFTER_INIT void MemoryManager::register_reserved_ranges()