142 lines
3.3 KiB
C++
142 lines
3.3 KiB
C++
#include "pmm.hpp"
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#include <base.hpp>
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enum class DEVICETYPE: uint8_t {
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PC,
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CONSOLE,
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EMBEDDED
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};
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enum class CPUARCH: uint8_t {
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X86,
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X86_64,
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ARM
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};
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enum class ENDIAN: uint8_t {
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BIG,
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LITTLE
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};
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enum class PERM: uint8_t {
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NONE,
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X,
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W,
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WX,
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R,
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RX,
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RW,
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RWX
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};
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struct MMAP {
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char magic[4];
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uint32_t version;
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uint32_t length;
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}__attribute__((packed));
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union MMAPTag {
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struct {
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uint8_t id;
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uint8_t size;
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}__attribute__((packed));
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struct {
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uint8_t id;
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uint8_t size;
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DEVICETYPE value;
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}__attribute__((packed)) DEVICETYPE;
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struct {
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uint8_t id;
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uint8_t size;
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char value[1];
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}__attribute__((packed)) DEVICENAME;
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struct {
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uint8_t id;
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uint8_t size;
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CPUARCH value;
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}__attribute__((packed)) CPUARCH;
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struct {
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uint8_t id;
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uint8_t size;
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ENDIAN endian;
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}__attribute__((packed)) ENDIAN;
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struct {
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uint8_t id;
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uint8_t size;
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uint8_t value;
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}__attribute__((packed)) BITS;
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struct {
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uint8_t id;
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uint8_t size;
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phys_t start;
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phys_t end;
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PERM permission;
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}__attribute__((packed)) REGION;
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};
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extern uint8_t mmap;
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PMM_MMAP::PMM_MMAP(): PMM(0x1000) {
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MMAP &header = *((MMAP*)&mmap);
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if((header.magic[0] != 'M')||(header.magic[1] != 'M')||(header.magic[2] != 'A')||(header.magic[3] != 'P'))
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for(;;); //This is not a mmap
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#ifdef __BIG_ENDIAN__
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header.length = __builtin_bswap32(header.length);
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#endif
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uint8_t *off=(uint8_t*)(&header+1);
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for(uint32_t i=0;i<header.length;i++) {
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MMAPTag &tag = *((MMAPTag*)off);
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off+=tag.size+2;
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switch(tag.id) {
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case 0:
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case 1:
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break; //Ignored for now
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case 2: //CPUARCH
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if(tag.CPUARCH.value !=
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#ifdef __i386__
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CPUARCH::X86
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#else
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#ifdef __x86_64__
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CPUARCH::X86_64
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#else
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CPUARCH::ARM
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#endif
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#endif
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)
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for(;;);
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break;
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case 3:
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hostEndian = tag.ENDIAN.endian ==
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#ifdef __BIG_ENDIAN__
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ENDIAN::BIG
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#else
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ENDIAN::LITTLE
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#endif
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;
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break;
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case 4:
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bits = tag.BITS.value;
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break;
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case 5:
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if(tag.REGION.permission != PERM::RWX)
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break;
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if(tag.REGION.start < lowest_page)
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lowest_page = tag.REGION.start;
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if(tag.REGION.end > highest_page)
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highest_page = tag.REGION.end;
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break;
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default:
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for(;;);
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}
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}
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fill();
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}
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PMM_MMAP::~PMM_MMAP() {}
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auto PMM_MMAP::isFree(phys_t addr) -> bool {
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MMAP &header = *((MMAP*)&mmap);
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uint8_t *off=(uint8_t*)(&header+1);
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for(uint32_t i=0;i<header.length;i++) {
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MMAPTag &tag = *((MMAPTag*)off);
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off+=tag.size+2;
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if(tag.id != 5)
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continue;
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if((tag.REGION.start > addr) || (tag.REGION.end <= addr))
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continue;
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if(tag.REGION.permission == PERM::RWX)
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return PMM::isFree(addr);
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}
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return false;
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}
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