Author: nwhitehorn
Date: Fri Oct 23 14:27:40 2009
New Revision: 198400
URL: http://svn.freebsd.org/changeset/base/198400
Log:
Do not map the trap vectors into the kernel's address space. They are
only used in real mode and keeping them mapped only serves to make NULL
a valid address, which results in silent NULL pointer deferences.
Suggested by: Patrick Kerharo
Obtained from: projects/ppc64
Modified:
head/sys/powerpc/aim/mmu_oea64.c
head/sys/powerpc/aim/trap_subr.S
Modified: head/sys/powerpc/aim/mmu_oea64.c
==============================================================================
--- head/sys/powerpc/aim/mmu_oea64.c Fri Oct 23 14:22:51 2009
(r198399)
+++ head/sys/powerpc/aim/mmu_oea64.c Fri Oct 23 14:27:40 2009
(r198400)
@@ -868,15 +868,17 @@ moea64_bridge_bootstrap(mmu_t mmup, vm_o
ENABLE_TRANS(msr);
/*
- * Map certain important things, like ourselves and the exception
- * vectors
+ * Map certain important things, like ourselves.
+ *
+ * NOTE: We do not map the exception vector space. That code is
+ * used only in real mode, and leaving it unmapped allows us to
+ * catch NULL pointer deferences, instead of making NULL a valid
+ * address.
*/
DISABLE_TRANS(msr);
for (pa = kernelstart & ~PAGE_MASK; pa < kernelend; pa += PAGE_SIZE)
moea64_kenter(mmup, pa, pa);
- for (pa = EXC_RSVD; pa < EXC_LAST; pa += PAGE_SIZE)
- moea64_kenter(mmup, pa, pa);
ENABLE_TRANS(msr);
if (!ofw_real_mode) {
Modified: head/sys/powerpc/aim/trap_subr.S
==============================================================================
--- head/sys/powerpc/aim/trap_subr.S Fri Oct 23 14:22:51 2009
(r198399)
+++ head/sys/powerpc/aim/trap_subr.S Fri Oct 23 14:27:40 2009
(r198400)
@@ -275,10 +275,16 @@ CNAME(restorebridgesize) = .-CNAME(resto
/*
* Processor reset exception handler. These are typically
* the first instructions the processor executes after a
- * software reset.
+ * software reset. We do this in two bits so that we are
+ * not still hanging around in the trap handling region
+ * once the MMU is turned on.
*/
.globl CNAME(rstcode), CNAME(rstsize)
CNAME(rstcode):
+ ba cpu_reset
+CNAME(rstsize) = . - CNAME(rstcode)
+
+cpu_reset:
bl 1f
.space 124
@@ -296,7 +302,6 @@ CNAME(rstcode):
/* Should not be reached */
9:
b 9b
-CNAME(rstsize) = . - CNAME(rstcode)
#endif
/*
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