From: Heiko Carstens Date: Tue, 25 Feb 2025 09:53:10 +0000 (+0100) Subject: s390/traps: Fix test_monitor_call() inline assembly X-Git-Tag: v6.14-rc6~9^2~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5623bc23a1cb9f9a9470fa73b3a20321dc4c4870;p=thirdparty%2Fkernel%2Flinux.git s390/traps: Fix test_monitor_call() inline assembly 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 Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c index 24fee11b030d8..b746213d3110c 100644 --- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -285,10 +285,10 @@ 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"); }