Implement Supplemental Page Table (SPT) per thread along with structure for its entries, w/ G

src/vm/page.c

@@ -1,5 +1,25 @@
 #include "page.h"
 
+/* Hashing function needed for the SPT table. Returns a hash for an entry,
+   based on its upage. */
+unsigned
+page_hash (const struct hash_elem *e, UNUSED void *aux)
+{
+  struct page_entry *page = hash_entry (e, struct page_entry, elem);
+  return hash_ptr(page->upage);
+}
+
+/* Comparator function for the SPT table. Compares two entries based on their
+   upages. */
+bool
+page_less (const struct hash_elem *a_, const struct hash_elem *b_, UNUSED void *aux)
+{
+  const struct page_entry *a = hash_entry (a_, struct page_entry, elem);
+  const struct page_entry *b = hash_entry (b_, struct page_entry, elem);
+  return a->upage < b->upage;
+}
+
+
 /* Updates the 'owner' thread's page table entry for virtual address 'upage'
    to have a present bit of 0 and stores the specified swap slot value in the
    entry for later retrieval from disk. */
@@ -16,5 +36,4 @@ size_t
 page_get_swap (struct thread *owner, void *upage)
 {
 
-}
-
+}

src/vm/page.h

@@ -2,6 +2,29 @@
 #define VM_PAGE_H
 
 #include "threads/thread.h"
+#include "filesys/off_t.h"
+
+enum page_type {
+  PAGE_EXECUTABLE,
+  PAGE_EMPTY
+};
+
+struct page_entry {
+  enum page_type type; /* Type of Data that should go into the page */
+  void *upage;         /* Start Address of the User Page (Key of hash table). */
+
+  /* File Data */
+  struct file *file;   /* Pointer to the file for executables. */
+  off_t offset;        /* Offset of the page content within the file. */
+  uint32_t read_bytes; /* Number of bytes to read within the page. */
+  uint32_t zero_bytes; /* Number of bytes to zero within the page. */
+  bool writable;       /* Flag for whether this page is writable or not. */
+
+  struct hash_elem elem; /* An elem for the hash table. */
+};
+
+unsigned page_hash (const struct hash_elem *e, void *aux);
+bool page_less (const struct hash_elem *a_, const struct hash_elem *b_, void *aux);
 
 void page_set_swap (struct thread *, void *, size_t);
 size_t page_get_swap (struct thread *, void *);