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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-02-03 17:37:15 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-02-05 11:00:50 +0100 |
| commit | 8d7f6690cedb83456edd41c9bd583783f0703bf0 (patch) | |
| tree | b7b45c28d9f5d84b7e2aa1e813c32e6f18bd481e /arch/s390/kernel/head64.S | |
| parent | s390/dump: Fix dump memory detection (diff) | |
| download | linux-8d7f6690cedb83456edd41c9bd583783f0703bf0.tar.xz linux-8d7f6690cedb83456edd41c9bd583783f0703bf0.zip | |
s390: fix kernel crash due to linkage stack instructions
The kernel currently crashes with a low-address-protection exception
if a user space process executes an instruction that tries to use the
linkage stack. Set the base-ASTE origin and the subspace-ASTE origin
of the dispatchable-unit-control-table to point to a dummy ASTE.
Set up control register 15 to point to an empty linkage stack with no
room left.
A user space process with a linkage stack instruction will still crash
but with a different exception which is correctly translated to a
segmentation fault instead of a kernel oops.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/head64.S')
| -rw-r--r-- | arch/s390/kernel/head64.S | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S index b9e25ae2579c..d7c00507568a 100644 --- a/arch/s390/kernel/head64.S +++ b/arch/s390/kernel/head64.S @@ -59,7 +59,7 @@ ENTRY(startup_continue) .quad 0 # cr12: tracing off .quad 0 # cr13: home space segment table .quad 0xc0000000 # cr14: machine check handling off - .quad 0 # cr15: linkage stack operations + .quad .Llinkage_stack # cr15: linkage stack operations .Lpcmsk:.quad 0x0000000180000000 .L4malign:.quad 0xffffffffffc00000 .Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8 @@ -67,12 +67,15 @@ ENTRY(startup_continue) .Lparmaddr: .quad PARMAREA .align 64 -.Lduct: .long 0,0,0,0,.Lduald,0,0,0 +.Lduct: .long 0,.Laste,.Laste,0,.Lduald,0,0,0 .long 0,0,0,0,0,0,0,0 +.Laste: .quad 0,0xffffffffffffffff,0,0,0,0,0,0 .align 128 .Lduald:.rept 8 .long 0x80000000,0,0,0 # invalid access-list entries .endr +.Llinkage_stack: + .long 0,0,0x89000000,0,0,0,0x8a000000,0 ENTRY(_ehead) |