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Modify pmap_pte() to support its use on non-current, non-kernel pmaps

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without holding Giant.
This commit is contained in:
Alan Cox 2004-09-01 18:04:22 +00:00
parent 0c601400a3
commit e33353b52b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=134607
1 changed files with 22 additions and 2 deletions
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24
sys/i386/i386/pmap.c
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@ -244,6 +244,7 @@ static int PMAP1unchanged;
SYSCTL_INT(_debug, OID_AUTO, PMAP1unchanged, CTLFLAG_RD,
&PMAP1unchanged, 0,
"Number of times pmap_pte_quick didn't change PMAP1");
static struct mtx PMAP2mutex;
static PMAP_INLINE void free_pv_entry(pv_entry_t pv);
static pv_entry_t get_pv_entry(void);
@ -260,6 +261,7 @@ static vm_page_t pmap_allocpte(pmap_t pmap, vm_offset_t va);
static vm_page_t _pmap_allocpte(pmap_t pmap, unsigned ptepindex);
static int _pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m);
static pt_entry_t *pmap_pte_quick(pmap_t pmap, vm_offset_t va);
static void pmap_pte_release(pt_entry_t *pte);
static int pmap_unuse_pt(pmap_t, vm_offset_t);
static vm_offset_t pmap_kmem_choose(vm_offset_t addr);
#ifdef PAE
@ -378,6 +380,8 @@ pmap_bootstrap(firstaddr, loadaddr)
SYSMAP(pt_entry_t *, PMAP1, PADDR1, 1);
SYSMAP(pt_entry_t *, PMAP2, PADDR2, 1);
mtx_init(&PMAP2mutex, "PMAP2", NULL, MTX_DEF);
virtual_avail = va;
*CMAP1 = *CMAP2 = 0;
@ -730,7 +734,8 @@ pmap_is_current(pmap_t pmap)
}
/*
* If the given pmap is not the current pmap, Giant must be held.
* If the given pmap is not the current or kernel pmap, the returned pte must
* be released by passing it to pmap_pte_release().
*/
pt_entry_t *
pmap_pte(pmap_t pmap, vm_offset_t va)
@ -745,7 +750,7 @@ pmap_pte(pmap_t pmap, vm_offset_t va)
/* are we current address space or kernel? */
if (pmap_is_current(pmap))
return (vtopte(va));
GIANT_REQUIRED;
mtx_lock(&PMAP2mutex);
newpf = *pde & PG_FRAME;
if ((*PMAP2 & PG_FRAME) != newpf) {
*PMAP2 = newpf | PG_RW | PG_V | PG_A | PG_M;
@ -756,6 +761,18 @@ pmap_pte(pmap_t pmap, vm_offset_t va)
return (0);
}
/*
* Releases a pte that was obtained from pmap_pte(). Be prepared for the pte
* being NULL.
*/
static __inline void
pmap_pte_release(pt_entry_t *pte)
{
if ((pt_entry_t *)((vm_offset_t)pte & PAGE_MASK) == PADDR2)
mtx_unlock(&PMAP2mutex);
}
static __inline void
invlcaddr(void *caddr)
{
@ -837,6 +854,7 @@ pmap_extract(pmap_t pmap, vm_offset_t va)
}
pte = pmap_pte(pmap, va);
rtval = (*pte & PG_FRAME) | (va & PAGE_MASK);
pmap_pte_release(pte);
}
PMAP_UNLOCK(pmap);
return (rtval);
@ -2264,6 +2282,7 @@ pmap_change_wiring(pmap, va, wired)
* invalidate TLB.
*/
pmap_pte_set_w(pte, wired);
pmap_pte_release(pte);
PMAP_UNLOCK(pmap);
}
@ -2898,6 +2917,7 @@ pmap_mincore(pmap, addr)
PMAP_LOCK(pmap);
ptep = pmap_pte(pmap, addr);
pte = (ptep != NULL) ? *ptep : 0;
pmap_pte_release(ptep);
PMAP_UNLOCK(pmap);
if (pte != 0) {