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feat: implement frame table without thread safety

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This commit is contained in:
Themis Demetriades
2024-11-26 15:17:11 +00:00
parent 605050e38d
commit ea2725f606
5 changed files with 189 additions and 5 deletions
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42
src/userprog/process.c
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@@ -24,6 +24,9 @@
#include "threads/vaddr.h"
#include "threads/synch.h"
#include "devices/timer.h"
#ifdef VM
#include "vm/frame.h"
#endif
/* Defines the native number of bytes processed by the processor
(for the purposes of alignment). */
@@ -113,7 +116,10 @@ process_execute (const char *cmd)
return tid;
}
static void *get_usr_kpage (enum palloc_flags flags);
static void free_usr_kpage (void *kpage);
static bool install_page (void *upage, void *kpage, bool writable);
static bool process_init_stack (char *cmd_saveptr, void **esp, char *file_name);
static void *push_to_stack (void **esp, void *data, size_t data_size);
#define push_var_to_stack(esp, var) (push_to_stack (esp, &var, sizeof (var)))
@@ -253,7 +259,7 @@ process_init_stack (char *cmd_saveptr, void **esp, char *file_name)
/* Allocate the pages and map them to the user process. */
for (int i = 1; i < pages_needed + 1; i++)
{
uint8_t *kpage = palloc_get_page (PAL_USER | PAL_ZERO);
uint8_t *kpage = get_usr_kpage (PAL_ZERO);
if (!install_page (((uint8_t *) PHYS_BASE) - PGSIZE * (i + 1),
kpage, true))
return false;
@@ -704,7 +710,7 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
if (kpage == NULL){
/* Get a new page of memory. */
kpage = palloc_get_page (PAL_USER);
kpage = get_usr_kpage (0);
if (kpage == NULL){
return false;
}
@@ -712,7 +718,7 @@ load_segment (struct file *file, off_t ofs, uint8_t *upage,
/* Add the page to the process's address space. */
if (!install_page (upage, kpage, writable))
{
palloc_free_page (kpage);
free_usr_kpage (kpage);
return false;
}
@@ -747,18 +753,44 @@ setup_stack (void **esp)
uint8_t *kpage;
bool success = false;
kpage = palloc_get_page (PAL_USER | PAL_ZERO);
kpage = get_usr_kpage (PAL_ZERO);
if (kpage != NULL)
{
success = install_page (((uint8_t *) PHYS_BASE) - PGSIZE, kpage, true);
if (success)
*esp = PHYS_BASE;
else
palloc_free_page (kpage);
free_usr_kpage (kpage);
}
return success;
}
/* Claims a page from the user pool and returns its kernel address,
updating the frame table if VM is enabled. */
static void *
get_usr_kpage (enum palloc_flags flags)
{
void *page;
#ifdef VM
page = frame_alloc (flags);
#else
page = palloc_get_page (flags | PAL_USER);
#endif
return page;
}
/* Frees a page belonging to a user process given its kernel address,
updating the frame table if VM is enabled. */
static void
free_usr_kpage (void *kpage)
{
#ifdef VM
frame_free (kpage);
#else
palloc_free_page (kpage);
#endif
}
/* Adds a mapping from user virtual address UPAGE to kernel
virtual address KPAGE to the page table.
If WRITABLE is true, the user process may modify the page;