forked from Bananymous/banan-os
66 lines
1.6 KiB
C++
66 lines
1.6 KiB
C++
#include <kernel/Paging.h>
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#include <kernel/panic.h>
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namespace Paging
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{
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static uint32_t s_page_directory[1024] __attribute__((aligned(4096)));
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static uint32_t s_page_table[1024] __attribute__((aligned(4096)));
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static uint32_t s_page_table_framebuffer[1024] __attribute__((aligned(4096)));
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static uint32_t s_page_table_rsdp[1024] __attribute__((aligned(4096)));
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static uint32_t s_page_table_apic[1024] __attribute__((aligned(4096)));
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void Initialize()
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{
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for (uint32_t i = 0; i < 1024; i++)
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s_page_directory[i] = 0x00000002;
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for (uint32_t i = 0; i < 1024; i++)
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s_page_table[i] = (i << 12) | 0x03;
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s_page_directory[0] = (uint32_t)s_page_table | 0x03;
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asm volatile(
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"movl %%eax, %%cr3;"
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"movl %%cr0, %%eax;"
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"orl $0x80000001, %%eax;"
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"movl %%eax, %%cr0;"
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:: "a"(s_page_directory)
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);
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}
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static void MapPDE(uint32_t address, uint32_t* pt)
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{
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if ((address & 0xffc00000) != address)
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Kernel::panic("Trying to map non 4 MiB aligned address");
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uint32_t pd_index = address >> 22;
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if (!(s_page_directory[pd_index] & (1 << 0)))
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{
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// Identity map the whole page table
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for (uint32_t i = 0; i < 1024; i++)
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pt[i] = address | (i << 12) | 0x03;
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// Set the pde to point to page table
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s_page_directory[pd_index] = (uint32_t)pt | 0x03;
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// Flush TLB
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for (uint32_t i = 0; i < 1024; i++)
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asm volatile("invlpg (%0)" :: "r" (address | (i << 12)) : "memory");
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}
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}
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void MapFramebuffer(uint32_t address)
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{
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MapPDE(address, s_page_table_framebuffer);
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}
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void MapRSDP(uint32_t address)
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{
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MapPDE(address, s_page_table_rsdp);
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}
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void MapAPIC(uint32_t address)
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{
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MapPDE(address, s_page_table_apic);
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}
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} |