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Added x86_64 paging and ELF loader

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This commit is contained in:
Jozef Nagy 2025-01-31 21:12:29 +01:00
parent 36ae3ec0b7
commit a39e30d17e
Signed by untrusted user who does not match committer: crz
GPG key ID: 459A4811CEAC7068
6 changed files with 309 additions and 4 deletions
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68
boot/arch/x86_64/common/mm/paging.c Normal file
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/*********************************************************************************/
/* Module Name: paging.c */
/* Project: AurixOS */
/* */
/* Copyright (c) 2024-2025 Jozef Nagy */
/* */
/* This source is subject to the MIT License. */
/* See License.txt in the root of this repository. */
/* All other rights reserved. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR */
/* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, */
/* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE */
/* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER */
/* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, */
/* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
/* SOFTWARE. */
/*********************************************************************************/
#include <mm/mman.h>
#include <mm/vmm.h>
#include <lib/string.h>
#include <print.h>
#include <stdint.h>
/* Trimmed down version of */
/* https://github.com/KevinAlavik/nekonix/blob/main/kernel/src/mm/vmm.c */
/* Thanks, Kevin <3 */
void map_page(uintptr_t *pm, uintptr_t virt, uintptr_t phys, uint64_t flags)
{
uint64_t pml1_idx = (virt & (uint64_t)0x1ff << 12) >> 12;
uint64_t pml2_idx = (virt & (uint64_t)0x1ff << 21) >> 21;
uint64_t pml3_idx = (virt & (uint64_t)0x1ff << 30) >> 30;
uint64_t pml4_idx = (virt & (uint64_t)0x1ff << 39) >> 39;
if (!(pm[pml4_idx] & 1)) {
pm[pml4_idx] = (uint64_t)mem_alloc(PAGE_SIZE) | flags;
}
uint64_t *pml3_table = (uint64_t *)(pm[pml4_idx] & 0x000FFFFFFFFFF000);
if (!(pml3_table[pml3_idx] & 1)) {
pml3_table[pml3_idx] = (uint64_t)mem_alloc(PAGE_SIZE) | flags;
}
uint64_t *pml2_table = (uint64_t *)(pml3_table[pml3_idx] & 0x000FFFFFFFFFF000);
if (!(pml2_table[pml2_idx] & 1)) {
pml2_table[pml2_idx] = (uint64_t)mem_alloc(PAGE_SIZE) | flags;
}
uint64_t *pml1_table = (uint64_t *)(pml2_table[pml2_idx] & 0x000FFFFFFFFFF000);
pml1_table[pml1_idx] = phys | flags;
debug("map_page(): Mapped 0x%lx -> 0x%lx\n", phys, virt);
}
uintptr_t *create_pagemap()
{
uint64_t *pm = (uint64_t *)mem_alloc(PAGE_SIZE);
if (!pm) {
debug("create_pagemap(): Failed to allocate memory for a new pm.\n");
return NULL;
}
memset(pm, 0, PAGE_SIZE);
debug("create_pagemap(): Created new pm at 0x%lx\n", (uint64_t)pm);
return pm;
}

19
boot/common/init.c
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@ -19,23 +19,34 @@
#include <vfs/vfs.h>
#include <mm/mman.h>
#include <mm/vmm.h>
#include <loader/elf.h>
#include <print.h>
void axboot_init()
{
if (!vfs_init("\\")) {
debug("axboot_init(): Failed to mount boot drive! Halting...");
debug("axboot_init(): Failed to mount boot drive! Halting...\n");
// TODO: Halt
while (1);
}
// read kernel -> test read
char *buffer = NULL;
vfs_read("\\System\\axkrnl", &buffer);
char *kbuf = NULL;
vfs_read("\\System\\axkrnl", &kbuf);
// TODO: Do something with the kernel :p
uintptr_t *pm = create_pagemap();
if (!pm) {
debug("axboot_init(): Failed to create kernel pagemap! Halting...\n");
// TODO: Halt
while (1);
}
mem_free(buffer);
void *kernel_entry = (void *)elf_load(kbuf, pm);
(void)kernel_entry;
mem_free(kbuf);
while (1);
}

85
boot/common/loader/elf.c Normal file
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/*********************************************************************************/
/* Module Name: elf.c */
/* Project: AurixOS */
/* */
/* Copyright (c) 2024-2025 Jozef Nagy */
/* */
/* This source is subject to the MIT License. */
/* See License.txt in the root of this repository. */
/* All other rights reserved. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR */
/* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, */
/* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE */
/* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER */
/* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, */
/* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
/* SOFTWARE. */
/*********************************************************************************/
#include <loader/elf.h>
#include <mm/vmm.h>
#include <mm/mman.h>
#include <lib/string.h>
#include <lib/align.h>
#include <print.h>
#include <stdint.h>
/* https://github.com/KevinAlavik/nekonix/blob/main/kernel/src/proc/elf.c */
/* Thanks, Kevin <3 */
uint64_t elf_load(char *data, uintptr_t *pagemap)
{
struct elf_header *header = (struct elf_header *)data;
if (header->e_magic != ELF_MAGIC) {
debug("Invalid ELF magic: 0x%x", header->e_magic);
return 0;
}
if (header->e_class != 2) {
debug("Unsupported ELF class: %u", header->e_class);
return 0;
}
struct elf_program_header *ph = (struct elf_program_header *)(data + header->e_phoff);
for (uint16_t i = 0; i < header->e_phnum; i++) {
if (ph[i].p_type != PT_LOAD)
continue;
uint64_t vaddr_start = ALIGN_DOWN(ph[i].p_vaddr, PAGE_SIZE);
uint64_t vaddr_end = ALIGN_UP(ph[i].p_vaddr + ph[i].p_memsz, PAGE_SIZE);
uint64_t offset = ph[i].p_offset;
uint64_t flags = VMM_PRESENT;
if (ph[i].p_flags & PF_W)
flags |= VMM_WRITABLE;
if (!(ph[i].p_flags & PF_X))
flags |= VMM_NX;
for (uint64_t addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) {
uint64_t phys = (uint64_t)mem_alloc(PAGE_SIZE);
if (!phys) {
debug("Out of physical memory");
return 0;
}
map_page(pagemap, addr, phys, flags);
uint64_t file_offset = offset + (addr - vaddr_start);
if (file_offset < offset + ph[i].p_filesz) {
uint64_t to_copy = PAGE_SIZE;
if (file_offset + PAGE_SIZE > offset + ph[i].p_filesz)
to_copy = offset + ph[i].p_filesz - file_offset;
memcpy((void *)phys, data + file_offset, to_copy);
} else {
memset((void *)phys, 0, PAGE_SIZE);
}
}
}
debug("ELF loaded successfully, entry: 0x%lx", header->e_entry);
return header->e_entry;
}

29
boot/include/lib/align.h Normal file
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/*********************************************************************************/
/* Module Name: align.h */
/* Project: AurixOS */
/* */
/* Copyright (c) 2024-2025 Jozef Nagy */
/* */
/* This source is subject to the MIT License. */
/* See License.txt in the root of this repository. */
/* All other rights reserved. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR */
/* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, */
/* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE */
/* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER */
/* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, */
/* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
/* SOFTWARE. */
/*********************************************************************************/
#ifndef _LIB_ALIGN_H
#define _LIB_ALIGN_H
#include <stdint.h>
#define DIV_ROUND_UP(x,y) (((uint64_t)(x) + ((uint64_t)(y) - 1)) / (uint64_t)(y))
#define ALIGN_UP(x,y) (DIV_ROUND_UP(x, y) * (uint64_t)(y))
#define ALIGN_DOWN(x,y) (((uint64_t)(x) / (uint64_t)(y)) * (uint64_t)(y))
#endif /* _LIB_ALIGN_H */

77
boot/include/loader/elf.h Normal file
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/*********************************************************************************/
/* Module Name: elf.h */
/* Project: AurixOS */
/* */
/* Copyright (c) 2024-2025 Jozef Nagy */
/* */
/* This source is subject to the MIT License. */
/* See License.txt in the root of this repository. */
/* All other rights reserved. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR */
/* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, */
/* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE */
/* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER */
/* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, */
/* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
/* SOFTWARE. */
/*********************************************************************************/
#ifndef _LOADER_ELF_H
#define _LOADER_ELF_H
#include <stdint.h>
//#include <stddef.h>
#define ELF_MAGIC 0x464C457F
struct elf_header {
uint32_t e_magic;
uint8_t e_class;
uint8_t e_data;
uint8_t e_version;
uint8_t e_osabi;
uint8_t e_abiversion;
uint8_t e_pad[7];
uint16_t e_type;
uint16_t e_machine;
uint32_t e_version2;
uint64_t e_entry;
uint64_t e_phoff;
uint64_t e_shoff;
uint32_t e_flags;
uint16_t e_ehsize;
uint16_t e_phentsize;
uint16_t e_phnum;
uint16_t e_shentsize;
uint16_t e_shnum;
uint16_t e_shstrndx;
} __attribute__((packed));
struct elf_program_header {
uint32_t p_type;
uint32_t p_flags;
uint64_t p_offset;
uint64_t p_vaddr;
uint64_t p_paddr;
uint64_t p_filesz;
uint64_t p_memsz;
uint64_t p_align;
} __attribute__((packed));
#define PT_NULL 0
#define PT_LOAD 1
#define PT_DYNAMIC 2
#define PT_INTERP 3
#define PT_NOTE 4
#define PT_SHLIB 5
#define PT_PHDR 6
#define PT_TLS 7
#define PF_X 0x1
#define PF_W 0x2
#define PF_R 0x4
uint64_t elf_load(char *kernel, uintptr_t *pagemap);
#endif /* _LOADER_ELF_H */

35
boot/include/mm/vmm.h Normal file
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@ -0,0 +1,35 @@
/*********************************************************************************/
/* Module Name: vmm.h */
/* Project: AurixOS */
/* */
/* Copyright (c) 2024-2025 Jozef Nagy */
/* */
/* This source is subject to the MIT License. */
/* See License.txt in the root of this repository. */
/* All other rights reserved. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR */
/* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, */
/* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE */
/* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER */
/* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, */
/* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
/* SOFTWARE. */
/*********************************************************************************/
#ifndef _MM_VMM_H
#define _MM_VMM_H
#include <arch/mm/paging.h>
#include <stdint.h>
#define VMM_PRESENT 1
#define VMM_WRITABLE 2
#define VMM_NX (1ull << 63)
#define VMM_USER 4
uintptr_t *create_pagemap(void);
void map_page(uintptr_t *pm, uintptr_t virt, uintptr_t phys, uint64_t flags);
#endif /* _MM_VMM_H */