From 50348fac29211a54702b375e6e5717198a7d0cf6 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 9 Aug 2021 10:30:49 +0200 Subject: [PATCH] net/iucv: get rid of register asm usage Using register asm statements has been proven to be very error prone, especially when using code instrumentation where gcc may add function calls, which clobbers register contents in an unexpected way. Therefore get rid of register asm statements in iucv code, even though there is currently nothing wrong with it. This way we know for sure that the above mentioned bug class won't be introduced here. Acked-by: Karsten Graul Signed-off-by: Heiko Carstens Signed-off-by: Karsten Graul Signed-off-by: David S. Miller --- net/iucv/iucv.c | 42 ++++++++++++++++++++++-------------------- 1 file changed, 22 insertions(+), 20 deletions(-) diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c index e6795d5a546a06..bebc7d09815d6a 100644 --- a/net/iucv/iucv.c +++ b/net/iucv/iucv.c @@ -286,19 +286,19 @@ static union iucv_param *iucv_param_irq[NR_CPUS]; */ static inline int __iucv_call_b2f0(int command, union iucv_param *parm) { - register unsigned long reg0 asm ("0"); - register unsigned long reg1 asm ("1"); - int ccode; + int cc; - reg0 = command; - reg1 = (unsigned long)parm; asm volatile( - " .long 0xb2f01000\n" - " ipm %0\n" - " srl %0,28\n" - : "=d" (ccode), "=m" (*parm), "+d" (reg0), "+a" (reg1) - : "m" (*parm) : "cc"); - return ccode; + " lgr 0,%[reg0]\n" + " lgr 1,%[reg1]\n" + " .long 0xb2f01000\n" + " ipm %[cc]\n" + " srl %[cc],28\n" + : [cc] "=&d" (cc), "+m" (*parm) + : [reg0] "d" ((unsigned long)command), + [reg1] "d" ((unsigned long)parm) + : "cc", "0", "1"); + return cc; } static inline int iucv_call_b2f0(int command, union iucv_param *parm) @@ -319,19 +319,21 @@ static inline int iucv_call_b2f0(int command, union iucv_param *parm) */ static int __iucv_query_maxconn(void *param, unsigned long *max_pathid) { - register unsigned long reg0 asm ("0"); - register unsigned long reg1 asm ("1"); - int ccode; + unsigned long reg1 = (unsigned long)param; + int cc; - reg0 = IUCV_QUERY; - reg1 = (unsigned long) param; asm volatile ( + " lghi 0,%[cmd]\n" + " lgr 1,%[reg1]\n" " .long 0xb2f01000\n" - " ipm %0\n" - " srl %0,28\n" - : "=d" (ccode), "+d" (reg0), "+d" (reg1) : : "cc"); + " ipm %[cc]\n" + " srl %[cc],28\n" + " lgr %[reg1],1\n" + : [cc] "=&d" (cc), [reg1] "+&d" (reg1) + : [cmd] "K" (IUCV_QUERY) + : "cc", "0", "1"); *max_pathid = reg1; - return ccode; + return cc; } static int iucv_query_maxconn(void)