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Add comments and slightly rearrange the thread stack assignment code

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to try make it less obscure.
This commit is contained in:
Julian Elischer 2002-07-03 20:47:50 +00:00
parent b2adb4b2c3
commit e04d8bf890
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=99381
2 changed files with 38 additions and 18 deletions
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28
sys/amd64/amd64/pmap.c
View File

@ -1012,23 +1012,29 @@ pmap_new_thread(struct thread *td)
#ifdef KSTACK_GUARD
/* get a kernel virtual address for the kstack for this thread */
ks = kmem_alloc_nofault(kernel_map,
(KSTACK_PAGES + 1) * PAGE_SIZE);
ks = kmem_alloc_nofault(kernel_map, (KSTACK_PAGES + 1) * PAGE_SIZE);
if (ks == 0)
panic("pmap_new_thread: kstack allocation failed");
ks += PAGE_SIZE;
td->td_kstack = ks;
ptek = vtopte(ks - PAGE_SIZE);
/*
* Set the first page to be the unmapped guard page.
*/
ptek = vtopte(ks);
oldpte = *ptek;
*ptek = 0;
if (oldpte) {
#ifdef I386_CPU
updateneeded = 1;
#else
invlpg(ks - PAGE_SIZE);
invlpg(ks);
#endif
}
/*
* move to the next page, which is where the real stack starts.
*/
ks += PAGE_SIZE;
td->td_kstack = ks;
ptek++;
#else
/* get a kernel virtual address for the kstack for this thread */
@ -1038,6 +1044,10 @@ pmap_new_thread(struct thread *td)
td->td_kstack = ks;
ptek = vtopte(ks);
#endif
/*
* For the length of the stack, link in a real page of ram for each
* page of stack.
*/
for (i = 0; i < KSTACK_PAGES; i++) {
/*
* Get a kernel stack page
@ -1050,16 +1060,16 @@ pmap_new_thread(struct thread *td)
m->wire_count++;
cnt.v_wire_count++;
oldpte = *(ptek + i);
/*
* Enter the page into the kernel address space.
*/
*(ptek + i) = VM_PAGE_TO_PHYS(m) | PG_RW | PG_V | pgeflag;
oldpte = ptek[i];
ptek[i] = VM_PAGE_TO_PHYS(m) | PG_RW | PG_V | pgeflag;
if (oldpte) {
#ifdef I386_CPU
updateneeded = 1;
#else
invlpg(ks + i * PAGE_SIZE);
invlpg(ks + (i * PAGE_SIZE));
#endif
}

28
sys/i386/i386/pmap.c
View File

@ -1012,23 +1012,29 @@ pmap_new_thread(struct thread *td)
#ifdef KSTACK_GUARD
/* get a kernel virtual address for the kstack for this thread */
ks = kmem_alloc_nofault(kernel_map,
(KSTACK_PAGES + 1) * PAGE_SIZE);
ks = kmem_alloc_nofault(kernel_map, (KSTACK_PAGES + 1) * PAGE_SIZE);
if (ks == 0)
panic("pmap_new_thread: kstack allocation failed");
ks += PAGE_SIZE;
td->td_kstack = ks;
ptek = vtopte(ks - PAGE_SIZE);
/*
* Set the first page to be the unmapped guard page.
*/
ptek = vtopte(ks);
oldpte = *ptek;
*ptek = 0;
if (oldpte) {
#ifdef I386_CPU
updateneeded = 1;
#else
invlpg(ks - PAGE_SIZE);
invlpg(ks);
#endif
}
/*
* move to the next page, which is where the real stack starts.
*/
ks += PAGE_SIZE;
td->td_kstack = ks;
ptek++;
#else
/* get a kernel virtual address for the kstack for this thread */
@ -1038,6 +1044,10 @@ pmap_new_thread(struct thread *td)
td->td_kstack = ks;
ptek = vtopte(ks);
#endif
/*
* For the length of the stack, link in a real page of ram for each
* page of stack.
*/
for (i = 0; i < KSTACK_PAGES; i++) {
/*
* Get a kernel stack page
@ -1050,16 +1060,16 @@ pmap_new_thread(struct thread *td)
m->wire_count++;
cnt.v_wire_count++;
oldpte = *(ptek + i);
/*
* Enter the page into the kernel address space.
*/
*(ptek + i) = VM_PAGE_TO_PHYS(m) | PG_RW | PG_V | pgeflag;
oldpte = ptek[i];
ptek[i] = VM_PAGE_TO_PHYS(m) | PG_RW | PG_V | pgeflag;
if (oldpte) {
#ifdef I386_CPU
updateneeded = 1;
#else
invlpg(ks + i * PAGE_SIZE);
invlpg(ks + (i * PAGE_SIZE));
#endif
}