[PATCH] kexec: s390 support

Add kexec support for s390 architecture.

From: Milton Miller <miltonm@bga.com>

- Fix passing of first argument to relocate_kernel assembly.
- Fix Kconfig description.
- Remove wrong comment and comments that describe obvious things.
- Allow only KEXEC_TYPE_DEFAULT as image type -> dump not supported.

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
new file mode 100644
index 000000000000..7a94db76df46
--- /dev/null
+++ b/arch/s390/kernel/machine_kexec.c
@@ -0,0 +1,98 @@
+/*
+ * arch/s390/kernel/machine_kexec.c
+ *
+ * (C) Copyright IBM Corp. 2005
+ *
+ * Author(s): Rolf Adelsberger <adelsberger@de.ibm.com>
+ *
+ */
+
+/*
+ * s390_machine_kexec.c - handle the transition of Linux booting another kernel
+ * on the S390 architecture.
+ */
+
+#include <asm/cio.h>
+#include <asm/setup.h>
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/system.h>
+
+static void kexec_halt_all_cpus(void *);
+
+typedef void (*relocate_kernel_t) (kimage_entry_t *, unsigned long);
+
+const extern unsigned char relocate_kernel[];
+const extern unsigned long long relocate_kernel_len;
+
+int
+machine_kexec_prepare(struct kimage *image)
+{
+        unsigned long reboot_code_buffer;
+
+        /* We don't support anything but the default image type for now. */
+        if (image->type != KEXEC_TYPE_DEFAULT)
+                return -EINVAL;
+
+        /* Get the destination where the assembler code should be copied to.*/
+        reboot_code_buffer = page_to_pfn(image->control_code_page)<<PAGE_SHIFT;
+
+        /* Then copy it */
+        memcpy((void *) reboot_code_buffer, relocate_kernel,
+               relocate_kernel_len);
+        return 0;
+}
+
+void
+machine_kexec_cleanup(struct kimage *image)
+{
+}
+
+void
+machine_shutdown(void)
+{
+        printk(KERN_INFO "kexec: machine_shutdown called\n");
+}
+
+NORET_TYPE void
+machine_kexec(struct kimage *image)
+{
+        clear_all_subchannels();
+
+        /* Disable lowcore protection */
+        ctl_clear_bit(0,28);
+
+        on_each_cpu(kexec_halt_all_cpus, image, 0, 0);
+        for(;;);
+}
+
+static void
+kexec_halt_all_cpus(void *kernel_image)
+{
+        static atomic_t cpuid = ATOMIC_INIT(-1);
+        int cpu;
+        struct kimage *image;
+        relocate_kernel_t data_mover;
+
+        if (atomic_compare_and_swap(-1, smp_processor_id(), &cpuid))
+                signal_processor(smp_processor_id(), sigp_stop);
+
+        /* Wait for all other cpus to enter stopped state */
+        for_each_online_cpu(cpu) {
+                if (cpu == smp_processor_id())
+                        continue;
+                while(!smp_cpu_not_running(cpu))
+                        cpu_relax();
+        }
+
+        image = (struct kimage *) kernel_image;
+        data_mover = (relocate_kernel_t)
+                (page_to_pfn(image->control_code_page) << PAGE_SHIFT);
+
+        /* Call the moving routine */
+        (*data_mover) (&image->head, image->start);
+}