i386/ucla/src/lab2/kern/pmap.h

   1 /* See COPYRIGHT for copyright information. */
   2
   3 #ifndef JOS_KERN_PMAP_H
   4 #define JOS_KERN_PMAP_H
   5 #ifndef JOS_KERNEL
   6 # error "This is a JOS kernel header; user programs should not #include it"
   7 #endif
   8
   9 #include <inc/memlayout.h>
  10 #include <inc/assert.h>
  11
  12
  13 /* This macro takes a kernel virtual address -- an address that points above
  14  * KERNBASE, where the machine's maximum 256MB of physical memory is mapped --
  15  * and returns the corresponding physical address.  It panics if you pass it a
  16  * non-kernel virtual address.
  17  */
  18 #define PADDR(kva)                                              \
  19 ({                                                              \
  20         physaddr_t __m_kva = (physaddr_t) (kva);                \
  21         if (__m_kva < KERNBASE)                                 \
  22                 panic("PADDR called with invalid kva %08lx", __m_kva);\
  23         __m_kva - KERNBASE;                                     \
  24 })
  25
  26 /* This macro takes a physical address and returns the corresponding kernel
  27  * virtual address.  It panics if you pass an invalid physical address. */
  28 #define KADDR(pa)                                               \
  29 ({                                                              \
  30         physaddr_t __m_pa = (pa);                               \
  31         uint32_t __m_ppn = PGNUM(__m_pa);                       \
  32         if (__m_ppn >= npages)                                  \
  33                 panic("KADDR called with invalid pa %08lx", __m_pa);\
  34         (void*) (__m_pa + KERNBASE);                            \
  35 })
  36
  37
  38 // Page structures.
  39 // Each Page describes one physical page.
  40 // The pages[] array keeps track of the state of physical memory.
  41 // Entry pages[N] holds information about physical page #N.
  42 // The machine has 'npages' pages of physical memory space.
  43 extern struct Page *pages;
  44 extern size_t npages;
  45
  46 struct Page {
  47         // Next page on the free list.
  48         Page *pp_link;
  49
  50         // Count of pointers to this page (usually in page table entries).
  51         // Reserved pages may not have valid reference counts.
  52         uint16_t pp_ref;
  53 };
  54
  55 extern pde_t *kern_pgdir;
  56
  57 extern struct Segdesc gdt[];
  58 extern struct Pseudodesc gdt_pd;
  59
  60 void    mem_init(void);
  61
  62 void    page_init(void);
  63 struct Page *page_alloc(void);
  64 void    page_free(struct Page *pp);
  65 int     page_insert(pde_t *pgdir, struct Page *pp, uintptr_t va, pte_t perm);
  66 void    page_remove(pde_t *pgdir, uintptr_t va);
  67 struct Page *page_lookup(pde_t *pgdir, uintptr_t va, pte_t **pte_store);
  68 void    page_decref(struct Page *pp);
  69
  70 void    tlb_invalidate(pde_t *pgdir, uintptr_t va);
  71
  72 static inline physaddr_t
  73 page2pa(struct Page *pp)
  74 {
  75         return (pp - pages) << PGSHIFT;
  76 }
  77
  78 static inline struct Page *
  79 pa2page(physaddr_t pa)
  80 {
  81         if (PGNUM(pa) >= npages)
  82                 panic("pa2page called with invalid pa");
  83         return &pages[PGNUM(pa)];
  84 }
  85
  86 static inline void *
  87 page2kva(struct Page *pp)
  88 {
  89         return KADDR(page2pa(pp));
  90 }
  91
  92 pte_t *pgdir_walk(pde_t *pgdir, uintptr_t va, int create);
  93
  94 #endif /* !JOS_KERN_PMAP_H */