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More paging stuff.

The test userspace process now runs at linear address 0x300000 which is
mapped to a dynamically allocated page from the MemoryManager. Cool!
This commit is contained in:
Andreas Kling 2018-10-18 13:05:00 +02:00
parent 89851a9ded
commit f67d695254
10 changed files with 339 additions and 66 deletions

View file

@ -2,6 +2,8 @@
#include "types.h"
#define PAGE_SIZE 4096u
union Descriptor {
struct {
WORD limit_lo;
@ -76,6 +78,42 @@ void writeGDTEntry(WORD selector, Descriptor&);
/* Map IRQ0-15 @ ISR 0x50-0x5F */
#define IRQ_VECTOR_BASE 0x50
struct PageFaultFlags {
enum Flags {
NotPresent = 0x00,
ProtectionViolation = 0x01,
Read = 0x00,
Write = 0x02,
UserMode = 0x04,
SupervisorMode = 0x00,
InstructionFetch = 0x08,
};
};
class PageFault {
public:
PageFault(word code, LinearAddress address)
: m_code(code)
, m_address(address)
{
}
LinearAddress address() const { return m_address; }
word code() const { return m_code; }
bool isNotPresent() const { return (m_code & 1) == PageFaultFlags::NotPresent; }
bool isProtectionViolation() const { return (m_code & 1) == PageFaultFlags::ProtectionViolation; }
bool isRead() const { return (m_code & 2) == PageFaultFlags::Read; }
bool isWrite() const { return (m_code & 2) == PageFaultFlags::Write; }
bool isUser() const { return (m_code & 4) == PageFaultFlags::UserMode; }
bool isSupervisor() const { return (m_code & 4) == PageFaultFlags::SupervisorMode; }
bool isInstructionFetch() const { return (m_code & 8) == PageFaultFlags::InstructionFetch; }
private:
word m_code;
LinearAddress m_address;
};
struct RegisterDump {
WORD gs;
WORD fs;
@ -95,3 +133,8 @@ struct RegisterDump {
DWORD eflags;
} PACKED;
inline constexpr dword pageBaseOf(dword address)
{
return address & 0xfffff000;
}