s390/smp: fix smp_stop_cpu() for !CONFIG_SMP

smp_stop_cpu() should stop the current cpu even for !CONFIG_SMP.
Otherwise machine_halt() will return and and the machine generates a
panic instread of simply stopping the current cpu:

Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000

CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 3.14.0-01527-g2b6ef16a6bc5 #10
[...]
Call Trace:
([<0000000000110db0>] show_trace+0xf8/0x158)
 [<0000000000110e7a>] show_stack+0x6a/0xe8
 [<000000000074dba8>] panic+0xe4/0x268
 [<0000000000140570>] do_exit+0xa88/0xb2c
 [<000000000016e12c>] SyS_reboot+0x1f0/0x234
 [<000000000075da70>] sysc_nr_ok+0x22/0x28
 [<000000007d5a09b4>] 0x7d5a09b4

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/sigp.h b/arch/s390/include/asm/sigp.h
index d091aa1aaf118e6ab3767c863d2813e84e99c077..bf9c823d4020ec2549aecba28996a08d9d69fdc4 100644 (file)
--- a/arch/s390/include/asm/sigp.h
+++ b/arch/s390/include/asm/sigp.h
@@ -31,4 +31,23 @@
 #define SIGP_STATUS_INCORRECT_STATE    0x00000200UL
 #define SIGP_STATUS_NOT_RUNNING                0x00000400UL
 
+#ifndef __ASSEMBLY__
+
+static inline int __pcpu_sigp(u16 addr, u8 order, u32 parm, u32 *status)
+{
+       register unsigned int reg1 asm ("1") = parm;
+       int cc;
+
+       asm volatile(
+               "       sigp    %1,%2,0(%3)\n"
+               "       ipm     %0\n"
+               "       srl     %0,28\n"
+               : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
+       if (status && cc == 1)
+               *status = reg1;
+       return cc;
+}
+
+#endif /* __ASSEMBLY__ */
+
 #endif /* __S390_ASM_SIGP_H */

diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h
index 16077939409622fc946b943f4556d91cc272211c..21703f85b48d8d0c1c1c229791a2cfe1dc9294d8 100644 (file)
--- a/arch/s390/include/asm/smp.h
+++ b/arch/s390/include/asm/smp.h
@@ -7,6 +7,8 @@
 #ifndef __ASM_SMP_H
 #define __ASM_SMP_H
 
+#include <asm/sigp.h>
+
 #ifdef CONFIG_SMP
 
 #include <asm/lowcore.h>
@@ -50,9 +52,18 @@ static inline int smp_store_status(int cpu) { return 0; }
 static inline int smp_vcpu_scheduled(int cpu) { return 1; }
 static inline void smp_yield_cpu(int cpu) { }
 static inline void smp_yield(void) { }
-static inline void smp_stop_cpu(void) { }
 static inline void smp_fill_possible_mask(void) { }
 
+static inline void smp_stop_cpu(void)
+{
+       u16 pcpu = stap();
+
+       for (;;) {
+               __pcpu_sigp(pcpu, SIGP_STOP, 0, NULL);
+               cpu_relax();
+       }
+}
+
 #endif /* CONFIG_SMP */
 
 #ifdef CONFIG_HOTPLUG_CPU

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 512ce1cde2a4ca03c88350db6520581436968ba9..86e65ec3422b9585a9281b7204bcfce24181f10d 100644 (file)
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -82,21 +82,6 @@ DEFINE_MUTEX(smp_cpu_state_mutex);
 /*
  * Signal processor helper functions.
  */
-static inline int __pcpu_sigp(u16 addr, u8 order, u32 parm, u32 *status)
-{
-       register unsigned int reg1 asm ("1") = parm;
-       int cc;
-
-       asm volatile(
-               "       sigp    %1,%2,0(%3)\n"
-               "       ipm     %0\n"
-               "       srl     %0,28\n"
-               : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
-       if (status && cc == 1)
-               *status = reg1;
-       return cc;
-}
-
 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
 {
        int cc;