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authorJohn David Anglin <dave.anglin@bell.net>2021-12-21 13:21:22 -0500
committerHelge Deller <deller@gmx.de>2021-12-21 21:07:39 +0100
commit8f66fce0f46560b9e910787ff7ad0974441c4f9c (patch)
treed5f798119ed692cec2c500360bc441ea5c87b8f3 /arch
parent484730e5862f6b872dca13840bed40fd7c60fa26 (diff)
parisc: Correct completer in lws start
The completer in the "or,ev %r1,%r30,%r30" instruction is reversed, so we are not clipping the LWS number when we are called from a 32-bit process (W=0). We need to nulify the following depdi instruction when the least-significant bit of %r30 is 1. If the %r20 register is not clipped, a user process could perform a LWS call that would branch to an undefined location in the kernel and potentially crash the machine. Signed-off-by: John David Anglin <dave.anglin@bell.net> Cc: stable@vger.kernel.org # 4.19+ Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/parisc/kernel/syscall.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index d2497b339d13..65c88ca7a7ac 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -472,7 +472,7 @@ lws_start:
extrd,u %r1,PSW_W_BIT,1,%r1
/* sp must be aligned on 4, so deposit the W bit setting into
* the bottom of sp temporarily */
- or,ev %r1,%r30,%r30
+ or,od %r1,%r30,%r30
/* Clip LWS number to a 32-bit value for 32-bit processes */
depdi 0, 31, 32, %r20