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Kernel: Move RAM size detection to MemoryManager and use what we learn.

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This commit is contained in:
Andreas Kling 2019-01-27 10:17:27 +01:00
parent c4c475b49d
commit 6d351bb326
3 changed files with 18 additions and 12 deletions
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19
Kernel/MemoryManager.cpp
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@ -6,6 +6,7 @@
#include "StdLib.h"
#include "Process.h"
#include <LibC/errno_numbers.h>
#include "CMOS.h"
//#define MM_DEBUG
//#define PAGE_FAULT_DEBUG
@ -19,6 +20,16 @@ MemoryManager& MM
MemoryManager::MemoryManager()
{
// FIXME: This is not the best way to do memory map detection.
// Rewrite to use BIOS int 15,e820 once we have VM86 support.
word base_memory = (CMOS::read(0x16) << 8) | CMOS::read(0x15);
word ext_memory = (CMOS::read(0x18) << 8) | CMOS::read(0x17);
kprintf("%u kB base memory\n", base_memory);
kprintf("%u kB extended memory\n", ext_memory);
m_ram_size = ext_memory * 1024;
m_kernel_page_directory = PageDirectory::create_at_fixed_address(PhysicalAddress(0x4000));
m_page_table_zero = (dword*)0x6000;
@ -75,14 +86,12 @@ void MemoryManager::initialize_paging()
// 1 MB -> 2 MB kmalloc_eternal() space.
// 2 MB -> 3 MB kmalloc() space.
// 3 MB -> 4 MB Supervisor physical pages (available for allocation!)
// 4 MB -> 32 MB Userspace physical pages (available for allocation!)
// 4 MB -> (max) MB Userspace physical pages (available for allocation!)
for (size_t i = (2 * MB); i < (4 * MB); i += PAGE_SIZE)
m_free_supervisor_physical_pages.append(adopt(*new PhysicalPage(PhysicalAddress(i), true)));
#ifdef MM_DEBUG
dbgprintf("MM: 4MB-32MB available for allocation\n");
#endif
for (size_t i = (4 * MB); i < (32 * MB); i += PAGE_SIZE)
dbgprintf("MM: 4MB-%uMB available for allocation\n", m_ram_size / 1048576);
for (size_t i = (4 * MB); i < m_ram_size; i += PAGE_SIZE)
m_free_physical_pages.append(adopt(*new PhysicalPage(PhysicalAddress(i), false)));
m_quickmap_addr = LinearAddress(m_free_physical_pages.take_last().leakRef()->paddr().get());
#ifdef MM_DEBUG