Author: nwhitehorn
Date: Sat Oct 26 20:57:26 2013
New Revision: 257196
URL: http://svnweb.freebsd.org/changeset/base/257196
Log:
Make devices with registers into the KVA region work reliably. Without this,
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.
Modified:
head/sys/powerpc/booke/pmap.c
Modified: head/sys/powerpc/booke/pmap.c
==============================================================================
--- head/sys/powerpc/booke/pmap.c Sat Oct 26 20:06:50 2013
(r257195)
+++ head/sys/powerpc/booke/pmap.c Sat Oct 26 20:57:26 2013
(r257196)
@@ -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_padd
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_pad
}
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
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
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