projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| d8dd4c12 GKH |
1 | From 8d7f6690cedb83456edd41c9bd583783f0703bf0 Mon Sep 17 00:00:00 2001 |
| 2 | From: Martin Schwidefsky <schwidefsky@de.ibm.com> | |
| 3 | Date: Mon, 3 Feb 2014 17:37:15 +0100 | |
| 4 | Subject: s390: fix kernel crash due to linkage stack instructions | |
| 5 | ||
| 6 | From: Martin Schwidefsky <schwidefsky@de.ibm.com> | |
| 7 | ||
| 8 | commit 8d7f6690cedb83456edd41c9bd583783f0703bf0 upstream. | |
| 9 | ||
| 10 | The kernel currently crashes with a low-address-protection exception | |
| 11 | if a user space process executes an instruction that tries to use the | |
| 12 | linkage stack. Set the base-ASTE origin and the subspace-ASTE origin | |
| 13 | of the dispatchable-unit-control-table to point to a dummy ASTE. | |
| 14 | Set up control register 15 to point to an empty linkage stack with no | |
| 15 | room left. | |
| 16 | ||
| 17 | A user space process with a linkage stack instruction will still crash | |
| 18 | but with a different exception which is correctly translated to a | |
| 19 | segmentation fault instead of a kernel oops. | |
| 20 | ||
| 21 | Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> | |
| 22 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 23 | ||
| 24 | --- | |
| 25 | arch/s390/kernel/head64.S | 7 +++++-- | |
| 26 | 1 file changed, 5 insertions(+), 2 deletions(-) | |
| 27 | ||
| 28 | --- a/arch/s390/kernel/head64.S | |
| 29 | +++ b/arch/s390/kernel/head64.S | |
| 30 | @@ -59,7 +59,7 @@ ENTRY(startup_continue) | |
| 31 | .quad 0 # cr12: tracing off | |
| 32 | .quad 0 # cr13: home space segment table | |
| 33 | .quad 0xc0000000 # cr14: machine check handling off | |
| 34 | - .quad 0 # cr15: linkage stack operations | |
| 35 | + .quad .Llinkage_stack # cr15: linkage stack operations | |
| 36 | .Lpcmsk:.quad 0x0000000180000000 | |
| 37 | .L4malign:.quad 0xffffffffffc00000 | |
| 38 | .Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8 | |
| 39 | @@ -67,12 +67,15 @@ ENTRY(startup_continue) | |
| 40 | .Lparmaddr: | |
| 41 | .quad PARMAREA | |
| 42 | .align 64 | |
| 43 | -.Lduct: .long 0,0,0,0,.Lduald,0,0,0 | |
| 44 | +.Lduct: .long 0,.Laste,.Laste,0,.Lduald,0,0,0 | |
| 45 | .long 0,0,0,0,0,0,0,0 | |
| 46 | +.Laste: .quad 0,0xffffffffffffffff,0,0,0,0,0,0 | |
| 47 | .align 128 | |
| 48 | .Lduald:.rept 8 | |
| 49 | .long 0x80000000,0,0,0 # invalid access-list entries | |
| 50 | .endr | |
| 51 | +.Llinkage_stack: | |
| 52 | + .long 0,0,0x89000000,0,0,0,0x8a000000,0 | |
| 53 | ||
| 54 | ENTRY(_ehead) | |
| 55 |