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Make devices with registers into the KVA region work reliably. Without this,

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previous KVA allocations (which the PMAP lazily invalidates) in TLB0 could
shadow device maps in TLB1. Add a big block comment about some of the
caveats with this approach.
This commit is contained in:
Nathan Whitehorn 2013-10-26 20:57:26 +00:00
parent 94f33b0ab6
commit 0b8a792e0b
1 changed files with 18 additions and 6 deletions
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24
sys/powerpc/booke/pmap.c
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@ -189,6 +189,7 @@ static tlb_entry_t tlb1[TLB1_ENTRIES];
/* Next free entry in the TLB1 */
static unsigned int tlb1_idx;
static vm_offset_t tlb1_map_base = VM_MAX_KERNEL_ADDRESS;
static tlbtid_t tid_alloc(struct pmap *);
@ -2681,11 +2682,23 @@ mmu_booke_mapdev_attr(mmu_t mmu, vm_paddr_t pa, vm_size_t size, vm_memattr_t ma)
size = roundup(size, PAGE_SIZE);
/*
* We leave a hole for device direct mapping between the maximum user
* address (0x8000000) and the minimum KVA address (0xc0000000). If
* devices are in there, just map them 1:1. If not, map them to the
* device mapping area about VM_MAX_KERNEL_ADDRESS. These mapped
* addresses should be pulled from an allocator, but since we do not
* ever free TLB1 entries, it is safe just to increment a counter.
* Note that there isn't a lot of address space here (128 MB) and it
* is not at all difficult to imagine running out, since that is a 4:1
* compression from the 0xc0000000 - 0xf0000000 address space that gets
* mapped there.
*/
if (pa >= (VM_MAXUSER_ADDRESS + PAGE_SIZE) &&
(pa + size - 1) < VM_MIN_KERNEL_ADDRESS)
va = pa;
else
va = kva_alloc(size);
va = atomic_fetchadd_int(&tlb1_map_base, size);
res = (void *)va;
do {
@ -3085,7 +3098,7 @@ tlb1_mapin_region(vm_offset_t va, vm_paddr_t pa, vm_size_t size)
}
mapped = (va - base);
debugf("mapped size 0x%08x (wasted space 0x%08x)\n",
printf("mapped size 0x%08x (wasted space 0x%08x)\n",
mapped, mapped - size);
return (mapped);
}
@ -3148,7 +3161,6 @@ tlb1_init()
vm_offset_t
pmap_early_io_map(vm_paddr_t pa, vm_size_t size)
{
static vm_offset_t early_io_map_base = VM_MAX_KERNEL_ADDRESS;
vm_paddr_t pa_base;
vm_offset_t va, sz;
int i;
@ -3165,14 +3177,14 @@ pmap_early_io_map(vm_paddr_t pa, vm_size_t size)
pa_base = trunc_page(pa);
size = roundup(size + (pa - pa_base), PAGE_SIZE);
va = early_io_map_base + (pa - pa_base);
va = tlb1_map_base + (pa - pa_base);
do {
sz = 1 << (ilog2(size) & ~1);
tlb1_set_entry(early_io_map_base, pa_base, sz, _TLB_ENTRY_IO);
tlb1_set_entry(tlb1_map_base, pa_base, sz, _TLB_ENTRY_IO);
size -= sz;
pa_base += sz;
early_io_map_base += sz;
tlb1_map_base += sz;
} while (size > 0);
#ifdef SMP