osdev/process.c at master · cstack/osdev · GitHub

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#include"process.h"

#include"assembly_interface.h"
#include"data_structures/page_table.h"
#include"memory.h"
#include"kernel_stdio.h"
#include"stdlib.h"

uint32_tnext_pid=0;

structprocess_t {
uint32_tpid;
page_directory_tpd;
};

voidcreate_process(structfile_t*file) {
structprocess_t*p=malloc(sizeof(structprocess_t));
p->pid=next_pid;
next_pid+=1;

page_in(TMP_PAGE_0);
page_directory_tpd=TMP_PAGE_0;
p->pd=pd;
void*pd_physical_address=virtual_to_physical(pd);

uint32_tpde=make_page_directory_entry(
pd_physical_address,
FOUR_KB,
 false,
 false,
SUPERVISOR,
READ_WRITE,
 true
 );
pd[1023] =pde;

page_in(TMP_PAGE_1);
page_table_tcode_pt=TMP_PAGE_1;
pde=make_page_directory_entry(
virtual_to_physical(code_pt),
FOUR_KB,
 false,
 false,
USER,
READ_ONLY,
 true
 );
pd[0] =pde;

page_in(TMP_PAGE_2);
void*user_code=TMP_PAGE_2;
uint32_tpte=make_page_table_entry(
virtual_to_physical(user_code),
 false,
 false,
 false,
USER,
READ_ONLY,
 true
 );
code_pt[0] =pte;

page_in(TMP_PAGE_3);
page_table_tstack_pt=TMP_PAGE_3;
pde=make_page_directory_entry(
virtual_to_physical(stack_pt),
FOUR_KB,
 false,
 false,
USER,
READ_WRITE,
 true
 );
pd[page_directory_offset(UPPER_GB_START) -1] =pde;

page_in(TMP_PAGE_4);
pte=make_page_table_entry(
virtual_to_physical(TMP_PAGE_4),
 false,
 false,
 false,
USER,
READ_WRITE,
 true
 );
stack_pt[1023] =pte;

map_kernel_into_page_directory(pd);

for (uint32_ti=0; i<file->size; i++) {
 ((char*)user_code)[i] = (file->bytes)[i];
 }

set_page_directory(virtual_to_physical(pd));

enter_user_mode();
}