I can't seem to type the correct words tonight. This should have read:
Move the OEA64 scratchpage to the end of KVA from the beginning, and set
its PVO to map physical address 0 instead of kernelstart. This fixes a
situation in which a user process could attempt to read this address
via KVM, have it fault while being modified, and then panic the kernel
because (a) it is supposed to map a valid address and (b) it lies in the
no-fault region between VM_MIN_KERNEL_ADDRESS and virtual_avail.
While here, move msgbuf and dpcpu back into regular KVA space for
consistency with other implementations.
-Nathan
Nathan Whitehorn wrote:
Author: nwhitehorn
Date: Thu Feb 25 03:53:21 2010
New Revision: 204297
URL: http://svn.freebsd.org/changeset/base/204297
Log:
Move the OEA64 scratchpage to the end of KVA from the beginning, and set
its PVO to map physical address 0 instead of kernelstart. This fixes a
situation in which a user process could attempt to return this address
via KVM, have it fault while being modified, and then panic the kernel
because (a) it is supposed to map a valid address and (b) it lies in the
no-fault region between VM_MIN_KERNEL_ADDRESS and virtual_avail.
While here, move msgbuf and dpcpu make into regular KVA space for
consistency with other implementations.
Modified:
head/sys/powerpc/aim/mmu_oea64.c
Modified: head/sys/powerpc/aim/mmu_oea64.c
==============================================================================
--- head/sys/powerpc/aim/mmu_oea64.c Thu Feb 25 03:49:17 2010
(r204296)
+++ head/sys/powerpc/aim/mmu_oea64.c Thu Feb 25 03:53:21 2010
(r204297)
@@ -970,10 +970,10 @@ moea64_bridge_bootstrap(mmu_t mmup, vm_o
mtx_init(&moea64_scratchpage_mtx, "pvo zero page", NULL, MTX_DEF);
for (i = 0; i < 2; i++) {
- moea64_scratchpage_va[i] = virtual_avail;
- virtual_avail += PAGE_SIZE;
+ moea64_scratchpage_va[i] = (virtual_end+1) - PAGE_SIZE;
+ virtual_end -= PAGE_SIZE;
- moea64_kenter(mmup,moea64_scratchpage_va[i],kernelstart);
+ moea64_kenter(mmup,moea64_scratchpage_va[i],0);
LOCK_TABLE();
moea64_scratchpage_pvo[i] = moea64_pvo_find_va(kernel_pmap,
@@ -1004,20 +1004,25 @@ moea64_bridge_bootstrap(mmu_t mmup, vm_o
* Allocate virtual address space for the message buffer.
*/
pa = msgbuf_phys = moea64_bootstrap_alloc(MSGBUF_SIZE, PAGE_SIZE);
- msgbufp = (struct msgbuf *)msgbuf_phys;
- while (pa - msgbuf_phys < MSGBUF_SIZE) {
- moea64_kenter(mmup, pa, pa);
+ msgbufp = (struct msgbuf *)virtual_avail;
+ va = virtual_avail;
+ virtual_avail += round_page(MSGBUF_SIZE);
+ while (va < virtual_avail) {
+ moea64_kenter(mmup, va, pa);
pa += PAGE_SIZE;
+ va += PAGE_SIZE;
}
/*
* Allocate virtual address space for the dynamic percpu area.
*/
pa = moea64_bootstrap_alloc(DPCPU_SIZE, PAGE_SIZE);
- dpcpu = (void *)pa;
- while (pa - (vm_offset_t)dpcpu < DPCPU_SIZE) {
- moea64_kenter(mmup, pa, pa);
+ dpcpu = (void *)virtual_avail;
+ virtual_avail += DPCPU_SIZE;
+ while (va < virtual_avail) {
+ moea64_kenter(mmup, va, pa);
pa += PAGE_SIZE;
+ va += PAGE_SIZE;
}
dpcpu_init(dpcpu, 0);
}
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