1 files changed, 38 insertions, 15 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 85060659fb1..818bd09c026 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -626,13 +626,17 @@ static int __cpuinit smp_alloc_lowcore(int cpu)
 	if (!lowcore)
 		return -ENOMEM;
 	async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
-	if (!async_stack)
-		goto out_async_stack;
 	panic_stack = __get_free_page(GFP_KERNEL);
-	if (!panic_stack)
-		goto out_panic_stack;
-
-	*lowcore = S390_lowcore;
+	if (!panic_stack || !async_stack)
+		goto out;
+	/*
+	 * Only need to copy the first 512 bytes from address 0. But since
+	 * the compiler emits a warning if src == NULL for memcpy use copy_page
+	 * instead. Copies more than needed but this code is not performance
+	 * critical.
+	 */
+	copy_page(lowcore, &S390_lowcore);
+	memset((void *)lowcore + 512, 0, sizeof(*lowcore) - 512);
 	lowcore->async_stack = async_stack + ASYNC_SIZE;
 	lowcore->panic_stack = panic_stack + PAGE_SIZE;
 
@@ -653,9 +657,8 @@ static int __cpuinit smp_alloc_lowcore(int cpu)
 out_save_area:
 	free_page(panic_stack);
 #endif
-out_panic_stack:
+out:
 	free_pages(async_stack, ASYNC_ORDER);
-out_async_stack:
 	free_pages((unsigned long) lowcore, lc_order);
 	return -ENOMEM;
 }
@@ -719,8 +722,8 @@ int __cpuinit __cpu_up(unsigned int cpu)
 	cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
 	cpu_lowcore->current_task = (unsigned long) idle;
 	cpu_lowcore->cpu_data.cpu_nr = cpu;
-	cpu_lowcore->softirq_pending = 0;
-	cpu_lowcore->ext_call_fast = 0;
+	cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
+	cpu_lowcore->ipl_device = S390_lowcore.ipl_device;
 	eieio();
 
 	while (signal_processor(cpu, sigp_restart) == sigp_busy)
@@ -797,23 +800,43 @@ void cpu_die(void)
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
+#ifndef CONFIG_64BIT
+	unsigned long save_area = 0;
+#endif
+	unsigned long async_stack, panic_stack;
+	struct _lowcore *lowcore;
 	unsigned int cpu;
+	int lc_order;
 
 	smp_detect_cpus();
 
 	/* request the 0x1201 emergency signal external interrupt */
 	if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
 		panic("Couldn't request external interrupt 0x1201");
-	memset(lowcore_ptr, 0, sizeof(lowcore_ptr));
 	print_cpu_info(&S390_lowcore.cpu_data);
-	smp_alloc_lowcore(smp_processor_id());
 
+	/* Reallocate current lowcore, but keep its contents. */
+	lc_order = sizeof(long) == 8 ? 1 : 0;
+	lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
+	panic_stack = __get_free_page(GFP_KERNEL);
+	async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 #ifndef CONFIG_64BIT
 	if (MACHINE_HAS_IEEE)
-		ctl_set_bit(14, 29); /* enable extended save area */
+		save_area = get_zeroed_page(GFP_KERNEL);
 #endif
-	set_prefix((u32)(unsigned long) lowcore_ptr[smp_processor_id()]);
-
+	local_irq_disable();
+	local_mcck_disable();
+	lowcore_ptr[smp_processor_id()] = lowcore;
+	*lowcore = S390_lowcore;
+	lowcore->panic_stack = panic_stack + PAGE_SIZE;
+	lowcore->async_stack = async_stack + ASYNC_SIZE;
+#ifndef CONFIG_64BIT
+	if (MACHINE_HAS_IEEE)
+		lowcore->extended_save_area_addr = (u32) save_area;
+#endif
+	set_prefix((u32)(unsigned long) lowcore);
+	local_mcck_enable();
+	local_irq_enable();
 	for_each_possible_cpu(cpu)
 		if (cpu != smp_processor_id())
 			smp_create_idle(cpu);