s390: simplify disabled_wait

The disabled_wait() function uses its argument as the PSW address when
it stops the CPU with a wait PSW that is disabled for interrupts.
The different callers sometimes use a specific number like 0xdeadbeef
to indicate a specific failure, the early boot code uses 0 and some
other calls sites use __builtin_return_address(0).

At the time a dump is created the current PSW and the registers of a
CPU are written to lowcore to make them avaiable to the dump analysis
tool. For a CPU stopped with disabled_wait the PSW and the registers
do not really make sense together, the PSW address does not point to
the function the registers belong to.

Simplify disabled_wait() by using _THIS_IP_ for the PSW address and
drop the argument to the function.

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

9 files changed, 13 insertions, 18 deletions

diff --git a/arch/s390/boot/als.c b/arch/s390/boot/als.c
index f902215e9cd9..ff6801d401c4 100644
--- a/arch/s390/boot/als.c
+++ b/arch/s390/boot/als.c
@@ -99,7 +99,7 @@ static void facility_mismatch(void)
         print_machine_type();
         print_missing_facilities();
         sclp_early_printk("See Principles of Operations for facility bits\n");
-        disabled_wait(0x8badcccc);
+        disabled_wait();
 }
 
 void verify_facilities(void)
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index 4401e992bda1..7b0d05414618 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -57,7 +57,7 @@ void error(char *x)
         sclp_early_printk(x);
         sclp_early_printk("\n\n -- System halted");
 
-        disabled_wait(0xdeadbeef);
+        disabled_wait();
 }
 
 #ifdef CONFIG_KERNEL_UNCOMPRESSED
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 9f2ff4a54aff..b0fcbc37b637 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -315,12 +315,12 @@ void enabled_wait(void);
 /*
  * Function to drop a processor into disabled wait state
  */
-static inline void __noreturn disabled_wait(unsigned long code)
+static inline void __noreturn disabled_wait(void)
 {
         psw_t psw;
 
         psw.mask = PSW_MASK_BASE | PSW_MASK_WAIT | PSW_MASK_BA | PSW_MASK_EA;
-        psw.addr = code;
+        psw.addr = _THIS_IP_;
         __load_psw(psw);
         while (1);
 }
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 33f704c16bd3..629f173f60cd 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -141,7 +141,7 @@ static void early_pgm_check_handler(void)
         addr = S390_lowcore.program_old_psw.addr;
         fixup = s390_search_extables(addr);
         if (!fixup)
-                disabled_wait(0);
+                disabled_wait();
         /* Disable low address protection before storing into lowcore. */
         __ctl_store(cr0, 0, 0);
         cr0_new = cr0 & ~(1UL << 28);
@@ -298,7 +298,7 @@ static void __init check_image_bootable(void)
         sclp_early_printk("Linux kernel boot failure: An attempt to boot a vmlinux ELF image failed.\n");
         sclp_early_printk("This image does not contain all parts necessary for starting up. Use\n");
         sclp_early_printk("bzImage or arch/s390/boot/compressed/vmlinux instead.\n");
-        disabled_wait(0xbadb007);
+        disabled_wait();
 }
 
 void __init startup_init(void)
diff --git a/arch/s390/kernel/early_nobss.c b/arch/s390/kernel/early_nobss.c
index 8d73f7fae16e..52a3ef959341 100644
--- a/arch/s390/kernel/early_nobss.c
+++ b/arch/s390/kernel/early_nobss.c
@@ -25,7 +25,7 @@ static void __init reset_tod_clock(void)
                 return;
         /* TOD clock not running. Set the clock to Unix Epoch. */
         if (set_tod_clock(TOD_UNIX_EPOCH) != 0 || store_tod_clock(&time) != 0)
-                disabled_wait(0);
+                disabled_wait();
 
         memset(tod_clock_base, 0, 16);
         *(__u64 *) &tod_clock_base[1] = TOD_UNIX_EPOCH;
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index aa8fe768640e..d836af3ccc38 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -920,7 +920,7 @@ static void __reipl_run(void *unused)
         case IPL_TYPE_FCP_DUMP:
                 break;
         }
-        disabled_wait((unsigned long) __builtin_return_address(0));
+        disabled_wait();
 }
 
 static void reipl_run(struct shutdown_trigger *trigger)
@@ -1375,7 +1375,7 @@ static void stop_run(struct shutdown_trigger *trigger)
 {
         if (strcmp(trigger->name, ON_PANIC_STR) == 0 ||
             strcmp(trigger->name, ON_RESTART_STR) == 0)
-                disabled_wait((unsigned long) __builtin_return_address(0));
+                disabled_wait();
         smp_stop_cpu();
 }
 
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index 2f3a742a71a5..8a1ae140c5e2 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -96,7 +96,7 @@ static void __do_machine_kdump(void *image)
         start_kdump(1);
 
         /* Die if start_kdump returns */
-        disabled_wait((unsigned long) __builtin_return_address(0));
+        disabled_wait();
 }
 
 /*
@@ -284,7 +284,7 @@ static void __do_machine_kexec(void *data)
         (*data_mover)(&image->head, image->start);
 
         /* Die if kexec returns */
-        disabled_wait((unsigned long) __builtin_return_address(0));
+        disabled_wait();
 }
 
 /*
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 8c867b43c8eb..0a487fae763e 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -125,7 +125,7 @@ void nmi_free_per_cpu(struct lowcore *lc)
 static notrace void s390_handle_damage(void)
 {
         smp_emergency_stop();
-        disabled_wait((unsigned long) __builtin_return_address(0));
+        disabled_wait();
         while (1);
 }
 NOKPROBE_SYMBOL(s390_handle_damage);
diff --git a/kernel/panic.c b/kernel/panic.c
index 0ae0d7332f12..c1fcaad337b7 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -318,12 +318,7 @@ void panic(const char *fmt, ...)
         }
 #endif
 #if defined(CONFIG_S390)
-        {
-                unsigned long caller;
-
-                caller = (unsigned long)__builtin_return_address(0);
-                disabled_wait(caller);
-        }
+        disabled_wait();
 #endif
         pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
         local_irq_enable();