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authorHeiko Carstens <hca@linux.ibm.com>2025-02-25 10:53:10 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-03-13 13:01:58 +0100
commit845590b5a089c74c02096dedccb94f857217b65c (patch)
tree9c71e77b0e108ecdfd4c2824ff176b2bf5543c04
parent83732451a98619e3fa65bdb7d22423908c526e2c (diff)
s390/traps: Fix test_monitor_call() inline assembly
commit 5623bc23a1cb9f9a9470fa73b3a20321dc4c4870 upstream. The test_monitor_call() inline assembly uses the xgr instruction, which also modifies the condition code, to clear a register. However the clobber list of the inline assembly does not specify that the condition code is modified, which may lead to incorrect code generation. Use the lhi instruction instead to clear the register without that the condition code is modified. Furthermore this limits clearing to the lower 32 bits of val, since its type is int. Fixes: 17248ea03674 ("s390: fix __EMIT_BUG() macro") Cc: stable@vger.kernel.org Reviewed-by: Juergen Christ <jchrist@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/s390/kernel/traps.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index 160b2acba8db..908bae849843 100644
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -284,10 +284,10 @@ static void __init test_monitor_call(void)
return;
asm volatile(
" mc 0,0\n"
- "0: xgr %0,%0\n"
+ "0: lhi %[val],0\n"
"1:\n"
- EX_TABLE(0b,1b)
- : "+d" (val));
+ EX_TABLE(0b, 1b)
+ : [val] "+d" (val));
if (!val)
panic("Monitor call doesn't work!\n");
}