90 lines
2.4 KiB
C
90 lines
2.4 KiB
C
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#ifndef THREADS_VADDR_H
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#define THREADS_VADDR_H
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#include <debug.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include "threads/loader.h"
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/* Functions and macros for working with virtual addresses.
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See pte.h for functions and macros specifically for x86
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hardware page tables. */
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#define BITMASK(SHIFT, CNT) (((1ul << (CNT)) - 1) << (SHIFT))
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/* Page offset (bits 0:12). */
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#define PGSHIFT 0 /* Index of first offset bit. */
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#define PGBITS 12 /* Number of offset bits. */
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#define PGSIZE (1 << PGBITS) /* Bytes in a page. */
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#define PGMASK BITMASK(PGSHIFT, PGBITS) /* Page offset bits (0:12). */
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/* Offset within a page. */
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static inline unsigned pg_ofs (const void *va) {
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return (uintptr_t) va & PGMASK;
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}
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/* Virtual page number. */
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static inline uintptr_t pg_no (const void *va) {
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return (uintptr_t) va >> PGBITS;
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}
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/* Round up to nearest page boundary. */
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static inline void *pg_round_up (const void *va) {
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return (void *) (((uintptr_t) va + PGSIZE - 1) & ~PGMASK);
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}
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/* Round down to nearest page boundary. */
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static inline void *pg_round_down (const void *va) {
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return (void *) ((uintptr_t) va & ~PGMASK);
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}
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/* Base address of the 1:1 physical-to-virtual mapping. Physical
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memory is mapped starting at this virtual address. Thus,
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physical address 0 is accessible at PHYS_BASE, physical
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address address 0x1234 at (uint8_t *) PHYS_BASE + 0x1234, and
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so on.
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This address also marks the end of user programs' address
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space. Up to this point in memory, user programs are allowed
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to map whatever they like. At this point and above, the
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virtual address space belongs to the kernel. */
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#define PHYS_BASE ((void *) LOADER_PHYS_BASE)
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/* Returns true if VADDR is a user virtual address. */
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static inline bool
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is_user_vaddr (const void *vaddr)
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{
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return vaddr < PHYS_BASE;
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}
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/* Returns true if VADDR is a kernel virtual address. */
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static inline bool
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is_kernel_vaddr (const void *vaddr)
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{
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return vaddr >= PHYS_BASE;
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}
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/* Returns kernel virtual address at which physical address PADDR
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is mapped. */
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static inline void *
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ptov (uintptr_t paddr)
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{
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ASSERT ((void *) paddr < PHYS_BASE);
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return (void *) (paddr + PHYS_BASE);
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}
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/* Returns physical address at which kernel virtual address VADDR
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is mapped. */
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static inline uintptr_t
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vtop (const void *vaddr)
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{
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ASSERT (is_kernel_vaddr (vaddr));
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return (uintptr_t) vaddr - (uintptr_t) PHYS_BASE;
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}
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#endif /* threads/vaddr.h */
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