christoph/lecture-operating-system-development
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merged cleanup

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This commit is contained in:
Christoph Urlacher
2022-07-24 21:12:31 +02:00
parent 5ff3d72bfd
commit 6481bae5f6
92 changed files with 663 additions and 755 deletions
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36
c_os/kernel/Paging.cc
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@ -53,20 +53,20 @@
#include "user/lib/Logger.h"
// Bits fuer Eintraege in der Page-Table
#define PAGE_PRESENT 0x001
#define PAGE_WRITEABLE 0x002
#define PAGE_BIGSIZE 0x080
#define PAGE_RESERVED 0x800 // Bit 11 ist frei fuer das OS
constexpr const unsigned int PAGE_PRESENT = 0x001;
constexpr const unsigned int PAGE_WRITEABLE = 0x002;
constexpr const unsigned int PAGE_BIGSIZE = 0x080;
constexpr const unsigned int PAGE_RESERVED = 0x800; // Bit 11 ist frei fuer das OS
// Adresse des Page-Directory (benoetigt 4 KB)
#define PAGE_DIRECTORY 0x200000
constexpr const unsigned int PAGE_DIRECTORY = 0x200000;
// Adresse der Page-Table (benoetigt 4 KB)
#define PAGE_TABLE 0x201000
constexpr const unsigned int PAGE_TABLE = 0x201000;
// Start- und End-Adresse der 4 KB Seiten die durch die Page-Table adressiert werden
#define FST_ALLOCABLE_PAGE 0x202000
#define LST_ALLOCABLE_PAGE 0x2FF000
constexpr const unsigned int FST_ALLOCABLE_PAGE = 0x202000;
constexpr const unsigned int LST_ALLOCABLE_PAGE = 0x2FF000;
/*****************************************************************************
* Funktion: pg_alloc_page *
@ -77,7 +77,7 @@
unsigned int* pg_alloc_page() {
unsigned int* p_page;
p_page = (unsigned int*)PAGE_TABLE;
p_page = reinterpret_cast<unsigned int*>(PAGE_TABLE);
// 1. Eintrag ist fuer Null-Pointer-Exception reserviert
// ausserdem liegt an die Page-Table an Adresse PAGE_TABLE
@ -87,10 +87,10 @@ unsigned int* pg_alloc_page() {
// pruefe ob Page frei
if (((*p_page) & PAGE_RESERVED) == 0) {
*p_page = (*p_page | PAGE_RESERVED);
return (unsigned int*)(i << 12); // Address without flags (Offset 0)
return reinterpret_cast<unsigned int*>(i << 12); // Address without flags (Offset 0)
}
}
return 0;
return nullptr;
}
/*****************************************************************************
@ -103,7 +103,7 @@ void pg_write_protect_page(const unsigned int* p_page) {
/* hier muss Code eingefügt werden */
unsigned int* page = (unsigned int*)PAGE_TABLE + ((unsigned int)p_page >> 12); // Pagetable entry
unsigned int* page = reinterpret_cast<unsigned int*>(PAGE_TABLE) + (reinterpret_cast<unsigned int>(p_page) >> 12); // Pagetable entry
unsigned int mask = PAGE_WRITEABLE; // fill to 32bit
*page = *page & ~mask; // set writable to 0
@ -118,7 +118,7 @@ void pg_notpresent_page(const unsigned int* p_page) {
/* hier muss Code eingefügt werden */
unsigned int* page = (unsigned int*)PAGE_TABLE + ((unsigned int)p_page >> 12); // Pagetable entry
unsigned int* page = reinterpret_cast<unsigned int*>(PAGE_TABLE) + (reinterpret_cast<unsigned int>(p_page) >> 12); // Pagetable entry
unsigned int mask = PAGE_PRESENT;
*page = *page & ~mask; // set present to 0
@ -131,7 +131,7 @@ void pg_notpresent_page(const unsigned int* p_page) {
* Bit geloescht. *
*****************************************************************************/
void pg_free_page(unsigned int* p_page) {
int idx = (unsigned int)p_page >> 12;
unsigned int idx = reinterpret_cast<unsigned int>(p_page) >> 12;
// ausserhalb Page ?
if (idx < 1 || idx > 1023) {
@ -139,7 +139,7 @@ void pg_free_page(unsigned int* p_page) {
}
// Eintrag einlesen und aendern (PAGE_WRITEABLE loeschen)
p_page = (unsigned int*)PAGE_TABLE;
p_page = reinterpret_cast<unsigned int*>(PAGE_TABLE);
p_page += idx;
*p_page = ((idx << 12) | PAGE_WRITEABLE | PAGE_PRESENT);
@ -170,7 +170,7 @@ void pg_init() {
//
// Eintrag 0: Zeiger auf 4 KB Page-Table
p_pdir = (unsigned int*)PAGE_DIRECTORY;
p_pdir = reinterpret_cast<unsigned int*>(PAGE_DIRECTORY);
*p_pdir = PAGE_TABLE | PAGE_WRITEABLE | PAGE_PRESENT;
// Eintraege 1-1023: Direktes Mapping (1:1) auf 4 MB Pages (ohne Page-Table)
@ -186,7 +186,7 @@ void pg_init() {
//
// 1. Page-Table
//
p_page = (unsigned int*)PAGE_TABLE;
p_page = reinterpret_cast<unsigned int*>(PAGE_TABLE);
// ersten Eintrag loeschen -> not present, write protected -> Null-Pointer abfangen
*p_page = 0;
@ -205,5 +205,5 @@ void pg_init() {
}
// Paging aktivieren (in startup.asm)
paging_on((unsigned int*)PAGE_DIRECTORY);
paging_on(reinterpret_cast<unsigned int*>(PAGE_DIRECTORY));
}