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#include "init.h"
#include "arch/x86_64/hal/msr.h"
#include "config.h"
#include "jove.h"
#include "hal/obj.h"
#include "lib/string.h"
#include "lib/panic.h"
#include "lib/printf.h"
#include "arch/x86_64/lib/elf.h"
#include "arch/x86_64/hal/paging.h"
#include "boot/cmdline.h"
#include "boot/initrd.h"
PAGEALIGN static page_t s_init_program_pml3[512];
PAGEALIGN static page_t s_init_program_pml2[512];
PAGEALIGN static page_t s_init_program_pml1[512];
PAGEALIGN static uint8_t s_init_program_pages[INIT_PROGRAM_PAGES_MAX][0x1000];
PAGEALIGN static page_t s_init_stack_pml3[512];
PAGEALIGN static page_t s_init_stack_pml2[512];
PAGEALIGN static page_t s_init_stack_pml1[512];
PAGEALIGN static uint8_t s_init_stack_pages[INIT_STACK_PAGES][0x1000];
static int
elf_is_valid(struct elf_header *ehdr)
{
if(ehdr->e_ident[0] != EI_MAG0 ||
ehdr->e_ident[1] != EI_MAG1 ||
ehdr->e_ident[2] != EI_MAG2 ||
ehdr->e_ident[3] != EI_MAG3) {
kprintf("ELF: Magic does not match!\n");
return 0;
}
if(ehdr->e_ident[4] != EI_CLASS_64) {
kprintf("ELF: Class is not 64-bit!\n");
return 0;
}
if(ehdr->e_ident[5] != EI_DATA_LE) {
kprintf("ELF: Data is not little-endian!\n");
return 0;
}
if(ehdr->e_type != ET_EXEC) {
kprintf("ELF: Program is not standard executable type!\n");
return 0;
}
if(ehdr->e_machine != EM_x86_64) {
kprintf("ELF: Executable is not x86_64!\n");
return 0;
}
return 1;
}
void
init_setup(void)
{
memset(s_init_program_pml3, 0, 0x1000);
memset(s_init_program_pml2, 0, 0x1000);
memset(s_init_program_pml1, 0, 0x1000);
memset(s_init_stack_pml3, 0, 0x1000);
memset(s_init_stack_pml2, 0, 0x1000);
memset(s_init_stack_pml1, 0, 0x1000);
uintptr_t init_program_pml3_pptr = KPTR_TOPHYS(&s_init_program_pml3);
uintptr_t init_program_pml2_pptr = KPTR_TOPHYS(&s_init_program_pml2);
uintptr_t init_program_pml1_pptr = KPTR_TOPHYS(&s_init_program_pml1);
uintptr_t init_program_pml0_pptr = KPTR_TOPHYS(&s_init_program_pages);
uintptr_t init_stack_pml3_pptr = KPTR_TOPHYS(&s_init_stack_pml3);
uintptr_t init_stack_pml2_pptr = KPTR_TOPHYS(&s_init_stack_pml2);
uintptr_t init_stack_pml1_pptr = KPTR_TOPHYS(&s_init_stack_pml1);
uintptr_t init_stack_pml0_pptr = KPTR_TOPHYS(&s_init_stack_pages);
//Get the init file data from the initrd.
const char *init_path = cmdline_getarg("init");
if(init_path == NULL) {
kpanic("Kernel commandline is missing 'init' arg.\n");
}
jove_owned_obj_t *initrd_obj = obj_take(objdir_getlocal(_rootdir_obj, ROOTDIR_INITRD_I));
jove_owned_obj_t *init_obj = initrd_seek(initrd_obj, init_path);
if(init_obj == NULL) {
kpanic("init: Cannot find file '%s' in initrd.\n", init_path);
}
obj_release(initrd_obj);
void *init_data = initrd_file_data(init_obj);
obj_release(init_obj);
struct elf_header *init_ehdr = init_data;
if(init_ehdr == NULL) {
kpanic("init: Cannot get file data for file '%s': %i\n", init_path, errno);
}
if(!elf_is_valid(init_ehdr)) {
kpanic("init: Either passed file '%s' is not an ELF file or is not loadable.\n", init_path);
}
jove_owned_obj_t *init_pagedir = obj_take(objdir_getlocal(_rootdir_obj, ROOTDIR_PAGEDIR_I));
page_t *pml4 = obj_deref(init_pagedir);
//Load the init ELF
for(size_t i = 0; i < init_ehdr->e_shnum; i++) {
struct elf_shdr *shdr = init_data + init_ehdr->e_shoff + i * init_ehdr->e_shentsize;
if(shdr->sh_type != SHT_PROGBITS && shdr->sh_type != SHT_NOBITS) continue;
if((shdr->sh_flags & SHF_ALLOC) == 0) continue;
uintptr_t base = shdr->sh_addr;
size_t limit = shdr->sh_size;
uintptr_t page_base = base & ~0xFFFULL;
size_t pml3i = (page_base >> PMLI_SHL(3)) & 0x1FF;
size_t pml2i = (page_base >> PMLI_SHL(2)) & 0x1FF;
size_t pml1i = (page_base >> PMLI_SHL(1)) & 0x1FF;
size_t base_pml0i = (page_base >> PMLI_SHL(0)) & 0x1FF;
pml4[pml3i].value = init_program_pml3_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER;
s_init_program_pml3[pml2i].value = init_program_pml2_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER;
s_init_program_pml2[pml1i].value = init_program_pml1_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER;
size_t pages = (limit + 4095) / 4096;
for(size_t pmlo = 0; pmlo < pages; pmlo++) {
size_t pml0i = base_pml0i + pmlo;
if(pml0i > INIT_PROGRAM_PAGES_MAX) {
kpanic("init: Program exceeds maximum program pages in the same hugepage frame!\n");
}
uintptr_t pml0_pptr = init_program_pml0_pptr + (pml0i << 12);
s_init_program_pml1[pml0i].value = pml0_pptr | PAGE_PRESENT | PAGE_USER | PAGE_WRITEABLE;
}
//Copy data from section if SHT_PROGBITS
if(shdr->sh_type == SHT_PROGBITS) {
memcpy((void*)shdr->sh_addr, init_data + shdr->sh_offset, shdr->sh_size);
}
}
//Map the stack
pml4[255].value = init_stack_pml3_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER | PAGE_XD;
s_init_stack_pml3[511].value = init_stack_pml2_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER | PAGE_XD;
s_init_stack_pml2[511].value = init_stack_pml1_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER | PAGE_XD;
for(size_t pmlo = 0; pmlo < INIT_STACK_PAGES; pmlo++) {
size_t pml0i = 511 - pmlo;
uintptr_t page_pptr = init_stack_pml0_pptr + (pmlo << 12);
s_init_stack_pml1[pml0i].value = page_pptr | PAGE_PRESENT | PAGE_WRITEABLE | PAGE_USER | PAGE_XD;
}
obj_release(init_pagedir);
//Enable syscalls
extern void _syscall_entry(void);
msr_set_lstar(_syscall_entry);
uintptr_t usp = 0x00007FFFFFFFFFF8;
uintptr_t uip = init_ehdr->e_entry;
__asm__ volatile("movq %0, %%rsp; \
movq %1, %%rcx; \
movq $0x202, %%r11; \
swapgs; \
sysretq"::
"r"(usp), "r"(uip): "memory");
}
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