Author: marcel
Date: Sat May 14 14:47:19 2011
New Revision: 221893
URL: http://svn.freebsd.org/changeset/base/221893
Log:
Sharpening the saw:
o Clobber the register that holds the restart token immediately after
crossing the restart point. This prevents false positives (i.e. a
nested exception that we don't know can happen and that is being
treated as one we know by virtue of a lingering restart token).
o Now that the bootstrap kernel stack is free, switch onto it and call
trap() for nested traps that we don't know about. In trap we panic()
so that we can analyze the condition.
Modified:
head/sys/ia64/ia64/exception.S
Modified: head/sys/ia64/ia64/exception.S
==============================================================================
--- head/sys/ia64/ia64/exception.S Sat May 14 14:42:12 2011
(r221892)
+++ head/sys/ia64/ia64/exception.S Sat May 14 14:47:19 2011
(r221893)
@@ -202,13 +202,13 @@ exception_save_restart:
{ .mmi
st8 [r30]=r19,16 // length
st8 [r31]=r0,16 // flags
- add r19=16,r19
+ add r29=16,r19 // Clobber restart token
;;
}
{ .mmi
st8.spill [r30]=sp,16 // sp
st8 [r31]=r20,16 // unat
- sub sp=r23,r19
+ sub sp=r23,r29
;;
}
{ .mmi
@@ -641,7 +641,7 @@ exception_restore_restart:
mov r30=ar.bspstore
;;
loadrs // load user regs
- nop 0
+ mov r29=0 // Clobber restart token
;;
}
{ .mmi
@@ -1094,22 +1094,26 @@ IVT_ENTRY(Data_Nested_TLB, 0x1400)
}
{ .mlx
mov r26=ar.bsp
- movl r27=kstack
+ movl r29=kstack
;;
}
-{ .mmi
+{ .mlx
mov r28=sp
- nop 0
- addl r27=KSTACK_PAGES*PAGE_SIZE-16,r0
+ movl r27=kstack_top
;;
}
{ .mmi
- mov sp=r27
+ add sp=-16,r27
;;
mov r27=ar.bspstore
nop 0
;;
}
+ mov ar.rsc=0
+ dep r29=r27,r29,0,9
+ ;;
+ mov ar.bspstore=r29
+ ;;
CALL(trap, 5, r30)
IVT_END(Data_Nested_TLB)
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