a cow based x86_64 operating system, using limine and stivale2
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4.6 KiB

#pragma once
#include <stdint.h>
/**
* general virtual memory map for Bincows:
*
* 0 ------------------
* | USER |
* | MEMORY |
* 0x0000007fffffffff |----------------|
* | |
* 0xffff800000000000 |----------------|
* | TRANSLATED |
* | MEMORY |
* 0xffff807fffffffff |----------------|
* | |
* 0xffffffff00000000 |----------------|
* | MMIO |
* 0xffffffff40000000 |----------------|
* | KERNEL TEMP |
* 0xffffffff80000000 |----------------|
* | KERNEL |
* | DATA |
* 0xffffffff80300000 |----------------|
* | KERNEL HEAP |
* 0xffffffffffffffff |----------------|
*
*
* the allocator and the page table manager
* share the same virtual space, in a translated
* physical memory space
*
*
*
* detailed MMIO address space:
*
* 0xffffffff00000000 |----- PCIE -----|
* | ... |
* | framebuffer |
* | ... |
* 0xffffffff1fffe000 |----------------|
* | HPET |
* 0xffffffff1ffff000 |----------------|
* | LAPIC |
* 0xffffffff20000000 |----------------|
*
*
* the KERNEL TEMP memory region is used
* for temporary allocations
* eg: copying data from one process to
* another
*
*
*
*/
#define HPET_VADDR 0xffffffff1fffe000llu
#define APIC_VADDR 0xffffffff1ffff000llu
/**
* early virtual memory map for Bincows:
*
*
* 0 ------------------
* | |
* | |
* 0xffff800000000000 |----------------|
* | TRANSLATED |
* | MEMORY |
* 0xffff8c0000000000 |----------------|
* | |
* 0xffffffff80000000 |----------------|
* | KERNEL |
* | DATA |
* 0xffffffffffffffff ------------------
*
*
*/
#define USER_END 0x0000007fffffffff
#define TRANSLATED_PHYSICAL_MEMORY_BEGIN 0xffff800000000000llu
#define MMIO_BEGIN 0xffffffff00000000llu
#define KERNEL_TEMP_BEGIN 0xffffffff40000000llu
#define KERNEL_DATA_BEGIN 0xffffffff80000000llu
#define KERNEL_HEAP_BEGIN 0xffffffff80300000llu
// Bincows segmentation
#define KERNEL_CS 0x08
#define KERNEL_DS 0x10
#define USER_CS 0x23
#define USER_DS 0x1b
#define USER_RF 0x202
/**
* user memory map for Bincows:
*
* 0 |----------------|
* | USER |
* | MEMORY |
* 0x0000007fffffffff |----------------|
*
*/
// return non 0 value iif the given address
// resides in kernel memory
static inline int is_user(void* vaddr) {
// user is in the lower half
return ((uint64_t)vaddr & ~USER_END) == 0;
}
static inline int is_kernel_memory(uint64_t vaddr) {
// kernel is in the 2 higher GB
return (vaddr & KERNEL_DATA_BEGIN) == KERNEL_DATA_BEGIN;
}
static inline int is_mmio(uint64_t vaddr) {
// between -4 GB and -3 GB
return (vaddr & (KERNEL_DATA_BEGIN | KERNEL_TEMP_BEGIN))
== MMIO_BEGIN;
}
static inline int is_higher_half(uint64_t vaddr) {
// higher half begins at TRANSLATED_PHYSICAL_MEMORY_BEGIN
return (vaddr & TRANSLATED_PHYSICAL_MEMORY_BEGIN)
== TRANSLATED_PHYSICAL_MEMORY_BEGIN;
}
// return the physical address of a
// stivale2 high half pointer
static inline uint64_t early_virtual_to_physical(
const void* vaddr) {
if((0xfffff00000000000llu & (uint64_t)vaddr) ==
TRANSLATED_PHYSICAL_MEMORY_BEGIN)
return ~TRANSLATED_PHYSICAL_MEMORY_BEGIN & (uint64_t)vaddr;
else
return ~KERNEL_DATA_BEGIN & (uint64_t)vaddr;
}
// translated virtual address that is in
// the TRANSLATED region to a physical address:
// (phys + TRANSLATED_PHYSICAL_MEMORY_BEGIN)
static inline uint64_t trv2p(void* trvaddr) {
return ((uint64_t)trvaddr & ~TRANSLATED_PHYSICAL_MEMORY_BEGIN);
}
static inline uint64_t trk2p(void* trkaddr) {
return ((uint64_t)trkaddr & ~KERNEL_DATA_BEGIN);
}
// translate a physical memory address
// to access it where it is mapped
static inline void* __attribute__((pure)) translate_address(void* phys_addr) {
return (void*)((uint64_t)phys_addr | TRANSLATED_PHYSICAL_MEMORY_BEGIN);
}