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In general, the kernel virtual address of the pml4 page table page that is

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stored in the pmap is from the direct map region.  The two exceptions have
been the kernel pmap and the swapper's pmap.  These pmaps have used a
kernel virtual address established by pmap_bootstrap() for their shared
pml4 page table page.  However, there is no reason not to use the direct
map for these pmaps as well.
This commit is contained in:
Alan Cox 2009-03-22 04:32:05 +00:00
parent cba3049682
commit 0c645b7267
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=190239
3 changed files with 10 additions and 4 deletions
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6
sys/amd64/amd64/pmap.c
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@ -542,7 +542,7 @@ pmap_bootstrap(vm_paddr_t *firstaddr)
* Initialize the kernel pmap (which is statically allocated).
*/
PMAP_LOCK_INIT(kernel_pmap);
kernel_pmap->pm_pml4 = (pdp_entry_t *) (KERNBASE + KPML4phys);
kernel_pmap->pm_pml4 = (pdp_entry_t *)PHYS_TO_DMAP(KPML4phys);
kernel_pmap->pm_root = NULL;
kernel_pmap->pm_active = -1; /* don't allow deactivation */
TAILQ_INIT(&kernel_pmap->pm_pvchunk);
@ -1351,7 +1351,7 @@ pmap_pinit0(pmap_t pmap)
{
PMAP_LOCK_INIT(pmap);
pmap->pm_pml4 = (pml4_entry_t *)(KERNBASE + KPML4phys);
pmap->pm_pml4 = (pml4_entry_t *)PHYS_TO_DMAP(KPML4phys);
pmap->pm_root = NULL;
pmap->pm_active = 0;
TAILQ_INIT(&pmap->pm_pvchunk);
@ -4695,7 +4695,7 @@ if (oldpmap) /* XXX FIXME */
oldpmap->pm_active &= ~PCPU_GET(cpumask);
pmap->pm_active |= PCPU_GET(cpumask);
#endif
cr3 = vtophys(pmap->pm_pml4);
cr3 = DMAP_TO_PHYS((vm_offset_t)pmap->pm_pml4);
td->td_pcb->pcb_cr3 = cr3;
load_cr3(cr3);
critical_exit();

4
sys/amd64/amd64/vm_machdep.c
View File

@ -103,6 +103,7 @@ cpu_fork(td1, p2, td2, flags)
register struct proc *p1;
struct pcb *pcb2;
struct mdproc *mdp2;
pmap_t pmap2;
p1 = td1->td_proc;
if ((flags & RFPROC) == 0)
@ -150,7 +151,8 @@ cpu_fork(td1, p2, td2, flags)
* Set registers for trampoline to user mode. Leave space for the
* return address on stack. These are the kernel mode register values.
*/
pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pml4);
pmap2 = vmspace_pmap(p2->p_vmspace);
pcb2->pcb_cr3 = DMAP_TO_PHYS((vm_offset_t)pmap2->pm_pml4);
pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */
pcb2->pcb_rbp = 0;
pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *);

4
sys/amd64/include/pmap.h
View File

@ -243,6 +243,10 @@ struct md_page {
TAILQ_HEAD(,pv_entry) pv_list;
};
/*
* The kernel virtual address (KVA) of the level 4 page table page is always
* within the direct map (DMAP) region.
*/
struct pmap {
struct mtx pm_mtx;
pml4_entry_t *pm_pml4; /* KVA of level 4 page table */