From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Wed, 17 Jun 2015 08:45:31 +0000 (+0200)
Subject: s390/smp: fix sigp cpu detection loop
X-Git-Tag: firefly_0821_release~176^2~1519^2~4
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e7086eb18119933753fceacfee662307b5e1d1c1;p=firefly-linux-kernel-4.4.55.git

s390/smp: fix sigp cpu detection loop

On a (theoretical) system where the read-cpu-info SCLP command does
not work but SMT is enabled, the sigp detection loop may not find
all configured cores. The maximum CPU address needs to be shifted
with smp_cpu_mt_shift.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 0d9d59d4710e..b3f1e9bb5e36 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -658,7 +658,8 @@ static struct sclp_cpu_info *smp_get_cpu_info(void)
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
 		use_sigp_detection = 1;
-		for (address = 0; address <= MAX_CPU_ADDRESS;
+		for (address = 0;
+		     address <= (MAX_CPU_ADDRESS << smp_cpu_mt_shift);
 		     address += (1U << smp_cpu_mt_shift)) {
 			if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
 			    SIGP_CC_NOT_OPERATIONAL)