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/** @file syscall_memory.c
*
* @brief memory syscalls.
*
* @author Hanjie Wu (hanjiew)
* @bug No functional bugs
*/
#include <string.h>
#include <common_kern.h>
#include <elf/elf_410.h>
#include <ureg.h>
#include <x86/asm.h>
#include <x86/cr.h>
#include <x86/eflags.h>
#include <x86/seg.h>
#include <asm_instr.h>
#include <malloc.h>
#include <mm.h>
#include <paging.h>
#include <sched.h>
#include <usermem.h>
/**
* @brief new_pages() syscall handler
* @param f saved regs
*/
void sys_new_pages_real(stack_frame_t* f) {
reg_t esi = f->esi;
va_t base;
if (copy_from_user((va_t)esi, sizeof(va_t), &base) != 0) {
goto read_fail;
}
if ((base & PAGE_OFFSET_MASK) != 0) {
goto read_fail;
}
int len;
if (copy_from_user((va_t)esi + sizeof(va_t), sizeof(int), &len) != 0) {
goto read_fail;
}
if ((len & PAGE_OFFSET_MASK) != 0) {
goto read_fail;
}
process_t* p = get_current()->process;
mutex_lock(&p->mm_lock);
int n_pages = len / PAGE_SIZE;
pa_t paddr = alloc_user_pages(n_pages);
if (paddr == 0) {
goto alloc_segment_fail;
}
if (add_region(p, base, n_pages, paddr, 1) != 0) {
goto add_region_fail;
}
int i = 0;
int offset = 0;
/* file page table one entry per loop */
pa_t pt_pa = find_or_create_pt(p, base);
if (pt_pa == BAD_PA) {
goto add_pt_fail;
}
do {
offset = i * PAGE_SIZE;
/* step to next page table */
int pt_index = get_pt_index(base + offset);
if (pt_index == 0) {
pt_pa = find_or_create_pt(p, base + offset);
if (pt_pa == BAD_PA) {
goto add_pt_fail;
}
}
int old_if = save_clear_if();
page_table_t* pt = (page_table_t*)map_phys_page(pt_pa, NULL);
(*pt)[pt_index] = make_pte(paddr + offset, 0, PTE_USER, PTE_RW, 0);
restore_if(old_if);
invlpg(base + offset);
} while (++i < n_pages);
mutex_unlock(&p->mm_lock);
f->eax = 0;
return;
add_pt_fail:
/* page tables are reachable from page directory so no need to free them */
vector_pop(&p->regions);
add_region_fail:
free_user_pages(paddr, n_pages);
alloc_segment_fail:
mutex_unlock(&p->mm_lock);
read_fail:
f->eax = (reg_t)-1;
}
/**
* @brief remove_pages() syscall handler
* @param f saved regs
*/
void sys_remove_pages_real(stack_frame_t* f) {
process_t* p = get_current()->process;
mutex_lock(&p->mm_lock);
va_t base = (va_t)f->esi;
int i, j, n = vector_size(&p->regions);
for (i = 0; i < n; i++) {
region_t* r = (region_t*)vector_at(&p->regions, i);
if (base == r->addr) {
int n_pages = r->size / PAGE_SIZE;
j = 0;
int offset = 0;
pa_t pt_pa = find_or_create_pt(p, base);
do {
offset = j * PAGE_SIZE;
int pt_index = get_pt_index(base + offset);
if (pt_index == 0) {
pt_pa = find_or_create_pt(p, base + offset);
}
int old_if = save_clear_if();
page_table_t* pt = (page_table_t*)map_phys_page(pt_pa, NULL);
(*pt)[pt_index] = BAD_PDE;
restore_if(old_if);
invlpg(base + offset);
} while (++j < n_pages);
free_user_pages(r->paddr, r->size / PAGE_SIZE);
vector_remove(&p->regions, i);
mutex_unlock(&p->mm_lock);
f->eax = 0;
return;
}
}
/* no such region */
mutex_unlock(&p->mm_lock);
f->eax = (reg_t)-1;
}
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