5.15-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
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 --- arch/s390/kernel/traps.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -281,10 +281,10 @@ static void __init test_monitor_call(voi 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"); }