154 lines
3.5 KiB
C
154 lines
3.5 KiB
C
#include <mem.h>
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#include <string.h>
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#include <debug.h>
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#include <int.h>
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#include <registers.h>
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#define STRIP_FLAGS(addr) ((void *)(((uintptr_t)(addr)) & ~PAGE_FLAGS_MASK))
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#define ADD_FLAGS(addr, flags) ((void *)(((uintptr_t)(addr)) | ((flags) & PAGE_FLAGS_MASK)))
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extern page_table BootP4;
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page_table *vmm_new_P4()
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{
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page_table *P4 = (page_table *)pmm_alloc();
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memset(P2V(P4), 0, PAGE_SIZE);
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((page_table *)P2V(P4))[511] = ((page_table *)&BootP4)[511];
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return P4;
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}
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void vmm_set_P4(page_table *P4)
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{
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write_cr3((uint64_t)P4);
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}
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void vmm_free_P4(page_table *P4)
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{
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P4 = P2V(P4);
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for(int i4=0; i4 < (int)P4_OFFSET(KERNEL_OFFSET); i4++)
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{
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if(P4[i4])
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{
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page_table *P3 = P2V(STRIP_FLAGS(P4[i4]));
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for(int i3=0; i3 < 0x200; i3++)
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{
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if(P3[i3])
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{
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page_table *P2 = P2V(STRIP_FLAGS(P3[i3]));
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for(int i2=0; i2 < 0x200; i2++)
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{
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if(P2[i2])
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{
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page_table *P1 = P2V(STRIP_FLAGS(P2[i2]));
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for(int i1=0; i1 < 0x200; i1++)
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{
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if(P1[i1])
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{
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pmm_free((uintptr_t)STRIP_FLAGS(P1[i1]));
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P1[i1] = 0;
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}
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}
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pmm_free((uintptr_t)STRIP_FLAGS(P2[i2]));
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P2[i2] = 0;
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}
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}
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pmm_free((uintptr_t)STRIP_FLAGS(P3[i3]));
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P3[i3] = 0;
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}
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}
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pmm_free((uintptr_t)STRIP_FLAGS(P4[i4]));
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P4[i4] = 0;
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}
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}
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pmm_free(V2P(P4));
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}
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void *vmm_find_page(page_table *P4, uintptr_t addr, uint32_t touch)
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{
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addr &= ~PAGE_FLAGS_MASK;
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page_table *P3, *P2, *P1;
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P4 = P2V(P4);
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if(!(P3 = P4[P4_OFFSET(addr)]))
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{
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if(!touch) return 0;
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uintptr_t p = pmm_alloc();
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memset(P2V(p), 0, PAGE_SIZE);
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P4[P4_OFFSET(addr)] = P3 = ADD_FLAGS(p, PAGE_PRESENT | PAGE_WRITE | PAGE_USER);
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}
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P3 = P2V(STRIP_FLAGS(P3));
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if(!(P2 = P3[P3_OFFSET(addr)]))
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{
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if(!touch) return 0;
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uintptr_t p = pmm_alloc();
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memset(P2V(p), 0, PAGE_SIZE);
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P3[P3_OFFSET(addr)] = P2 = ADD_FLAGS(p, PAGE_PRESENT | PAGE_WRITE | PAGE_USER);
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}
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P2 = P2V(STRIP_FLAGS(P2));
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if(!(P1 = P2[P2_OFFSET(addr)]))
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{
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if(!touch) return 0;
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uintptr_t p = pmm_alloc();
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memset(P2V(p), 0, PAGE_SIZE);
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P2[P2_OFFSET(addr)] = P1 = ADD_FLAGS(p, PAGE_PRESENT | PAGE_WRITE | PAGE_USER);
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}
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return P2V(STRIP_FLAGS(P1));
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}
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uintptr_t vmm_get_page(page_table *P4, uintptr_t addr)
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{
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page_table *P1;
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if(!P4) P4=GET_P4();
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if(!(P1 = vmm_find_page(P4, addr, 0))) return 0;
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return (uintptr_t)(P1[P1_OFFSET(addr)]);
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}
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uintptr_t vmm_set_page(page_table *P4, uintptr_t addr, uintptr_t phys, uint32_t flags)
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{
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page_table *P1;
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if(!P4) P4=GET_P4();
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if(!(P1 = vmm_find_page(P4, addr, 1))) return 0;
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P1[P1_OFFSET(addr)] = ADD_FLAGS(phys, flags);
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return (uintptr_t)P1[P1_OFFSET(addr)];
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}
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registers_t *page_fault_handler(registers_t *r)
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{
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debug("\n ===== PAGE FAULT =====\n");
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debug("Instruction at:%x tried to", r->rip);
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if(r->err_code & 0x2)
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debug(" read from");
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else if(r->err_code & 0xE)
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debug(" execute code from");
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else
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debug(" write to");
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debug(" memory \nat:%x in", read_cr2());
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if(r->err_code & 0x8)
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debug(" user mode");
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else
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debug(" kernel mode");
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debug("\n");
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debug("This caused a");
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if(r->err_code & 0x1)
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debug(" protection fault");
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else
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debug(" page miss");
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debug(".\n ======================\n");
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print_registers(r);
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#ifndef NDEBUG
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asm("page_fault_breakpoint:");
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#endif
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for(;;);
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}
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void vmm_init()
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{
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register_int_handler(0xE, page_fault_handler);
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}
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