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Take advantage of the fact that there is a small 1MB direct mapped region

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on x86 in between KERNBASE and the kernel load address.  pmap_mapdev()
can return pointers to this for devices operating in the isa "hole".
This commit is contained in:
Peter Wemm 2002-08-03 01:02:37 +00:00
parent 1af04fadd1
commit 8f1586dd65
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=101249
2 changed files with 22 additions and 16 deletions
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19
sys/amd64/amd64/pmap.c
View File

@ -3282,27 +3282,28 @@ pmap_mapdev(pa, size)
vm_size_t size;
{
vm_offset_t va, tmpva, offset;
pt_entry_t *pte;
offset = pa & PAGE_MASK;
size = roundup(offset + size, PAGE_SIZE);
size = round_page(offset + size);
pa = trunc_page(pa);
/* We have a 1MB direct mapped region at KERNBASE */
if (pa < 0x00100000 && pa + size <= 0x00100000)
return (void *)(pa + KERNBASE);
GIANT_REQUIRED;
va = kmem_alloc_pageable(kernel_map, size);
if (!va)
panic("pmap_mapdev: Couldn't alloc kernel virtual memory");
pa = pa & PG_FRAME;
for (tmpva = va; size > 0; ) {
pte = vtopte(tmpva);
*pte = pa | PG_RW | PG_V | pgeflag;
pmap_kenter(tmpva, pa);
size -= PAGE_SIZE;
tmpva += PAGE_SIZE;
pa += PAGE_SIZE;
}
pmap_invalidate_range(kernel_pmap, va, tmpva);
return ((void *)(va + offset));
return (void *)(va + offset);
}
void
@ -3315,7 +3316,9 @@ pmap_unmapdev(va, size)
base = va & PG_FRAME;
offset = va & PAGE_MASK;
size = roundup(offset + size, PAGE_SIZE);
size = round_page(offset + size);
if (base >= KERNBASE && va + size <= KERNBASE + 0x00100000)
return; /* direct mapped */
for (tmpva = base; tmpva < (base + size); tmpva += PAGE_SIZE) {
pte = vtopte(tmpva);
*pte = 0;

19
sys/i386/i386/pmap.c
View File

@ -3282,27 +3282,28 @@ pmap_mapdev(pa, size)
vm_size_t size;
{
vm_offset_t va, tmpva, offset;
pt_entry_t *pte;
offset = pa & PAGE_MASK;
size = roundup(offset + size, PAGE_SIZE);
size = round_page(offset + size);
pa = trunc_page(pa);
/* We have a 1MB direct mapped region at KERNBASE */
if (pa < 0x00100000 && pa + size <= 0x00100000)
return (void *)(pa + KERNBASE);
GIANT_REQUIRED;
va = kmem_alloc_pageable(kernel_map, size);
if (!va)
panic("pmap_mapdev: Couldn't alloc kernel virtual memory");
pa = pa & PG_FRAME;
for (tmpva = va; size > 0; ) {
pte = vtopte(tmpva);
*pte = pa | PG_RW | PG_V | pgeflag;
pmap_kenter(tmpva, pa);
size -= PAGE_SIZE;
tmpva += PAGE_SIZE;
pa += PAGE_SIZE;
}
pmap_invalidate_range(kernel_pmap, va, tmpva);
return ((void *)(va + offset));
return (void *)(va + offset);
}
void
@ -3315,7 +3316,9 @@ pmap_unmapdev(va, size)
base = va & PG_FRAME;
offset = va & PAGE_MASK;
size = roundup(offset + size, PAGE_SIZE);
size = round_page(offset + size);
if (base >= KERNBASE && va + size <= KERNBASE + 0x00100000)
return; /* direct mapped */
for (tmpva = base; tmpva < (base + size); tmpva += PAGE_SIZE) {
pte = vtopte(tmpva);
*pte = 0;