8956 Implement KPTI
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 22,32 ****
   * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
   */
  /*
   * Copyright (c) 2010, Intel Corporation.
   * All rights reserved.
!  * Copyright 2016 Joyent, Inc.
   */
  
  /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*      All Rights Reserved   */
  
--- 22,32 ----
   * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
   */
  /*
   * Copyright (c) 2010, Intel Corporation.
   * All rights reserved.
!  * Copyright 2018 Joyent, Inc.
   */
  
  /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*      All Rights Reserved   */
  
*** 362,372 ****
--- 362,457 ----
  #define CONTIG_LOCK()   mutex_enter(&contig_lock);
  #define CONTIG_UNLOCK() mutex_exit(&contig_lock);
  
  #define PFN_16M         (mmu_btop((uint64_t)0x1000000))
  
+ caddr_t
+ i86devmap(pfn_t pf, pgcnt_t pgcnt, uint_t prot)
+ {
+         caddr_t addr;
+         caddr_t addr1;
+         page_t *pp;
+ 
+         addr1 = addr = vmem_alloc(heap_arena, mmu_ptob(pgcnt), VM_SLEEP);
+ 
+         for (; pgcnt != 0; addr += MMU_PAGESIZE, ++pf, --pgcnt) {
+                 pp = page_numtopp_nolock(pf);
+                 if (pp == NULL) {
+                         hat_devload(kas.a_hat, addr, MMU_PAGESIZE, pf,
+                             prot | HAT_NOSYNC, HAT_LOAD_LOCK);
+                 } else {
+                         hat_memload(kas.a_hat, addr, pp,
+                             prot | HAT_NOSYNC, HAT_LOAD_LOCK);
+                 }
+         }
+ 
+         return (addr1);
+ }
+ 
  /*
+  * This routine is like page_numtopp, but accepts only free pages, which
+  * it allocates (unfrees) and returns with the exclusive lock held.
+  * It is used by machdep.c/dma_init() to find contiguous free pages.
+  */
+ page_t *
+ page_numtopp_alloc(pfn_t pfnum)
+ {
+         page_t *pp;
+ 
+ retry:
+         pp = page_numtopp_nolock(pfnum);
+         if (pp == NULL) {
+                 return (NULL);
+         }
+ 
+         if (!page_trylock(pp, SE_EXCL)) {
+                 return (NULL);
+         }
+ 
+         if (page_pptonum(pp) != pfnum) {
+                 page_unlock(pp);
+                 goto retry;
+         }
+ 
+         if (!PP_ISFREE(pp)) {
+                 page_unlock(pp);
+                 return (NULL);
+         }
+         if (pp->p_szc) {
+                 page_demote_free_pages(pp);
+                 page_unlock(pp);
+                 goto retry;
+         }
+ 
+         /* If associated with a vnode, destroy mappings */
+ 
+         if (pp->p_vnode) {
+ 
+                 page_destroy_free(pp);
+ 
+                 if (!page_lock(pp, SE_EXCL, (kmutex_t *)NULL, P_NO_RECLAIM)) {
+                         return (NULL);
+                 }
+ 
+                 if (page_pptonum(pp) != pfnum) {
+                         page_unlock(pp);
+                         goto retry;
+                 }
+         }
+ 
+         if (!PP_ISFREE(pp)) {
+                 page_unlock(pp);
+                 return (NULL);
+         }
+ 
+         if (!page_reclaim(pp, (kmutex_t *)NULL))
+                 return (NULL);
+ 
+         return (pp);
+ }
+ 
+ /*
   * Return the optimum page size for a given mapping
   */
  /*ARGSUSED*/
  size_t
  map_pgsz(int maptype, struct proc *p, caddr_t addr, size_t len, int memcntl)