1 files changed, 38 insertions, 15 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 85060659fb12..818bd09c0260 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);