[S390] kdump backend code

This patch provides the architecture specific part of the s390 kdump
support.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 155 insertions, 6 deletions

diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index b09b9c62573e..0ceac06a0299 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -1,10 +1,11 @@
 /*
  * arch/s390/kernel/machine_kexec.c
  *
- * Copyright IBM Corp. 2005,2006
+ * Copyright IBM Corp. 2005,2011
  *
  * Author(s): Rolf Adelsberger,
  *	      Heiko Carstens <heiko.carstens@de.ibm.com>
+ *	      Michael Holzheu <holzheu@linux.vnet.ibm.com>
  */
 
 #include <linux/device.h>
@@ -21,12 +22,131 @@
 #include <asm/smp.h>
 #include <asm/reset.h>
 #include <asm/ipl.h>
+#include <asm/diag.h>
+#include <asm/asm-offsets.h>
 
 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
 
 extern const unsigned char relocate_kernel[];
 extern const unsigned long long relocate_kernel_len;
 
+#ifdef CONFIG_CRASH_DUMP
+
+void *fill_cpu_elf_notes(void *ptr, struct save_area *sa);
+
+/*
+ * Create ELF notes for one CPU
+ */
+static void add_elf_notes(int cpu)
+{
+	struct save_area *sa = (void *) 4608 + store_prefix();
+	void *ptr;
+
+	memcpy((void *) (4608UL + sa->pref_reg), sa, sizeof(*sa));
+	ptr = (u64 *) per_cpu_ptr(crash_notes, cpu);
+	ptr = fill_cpu_elf_notes(ptr, sa);
+	memset(ptr, 0, sizeof(struct elf_note));
+}
+
+/*
+ * Store status of next available physical CPU
+ */
+static int store_status_next(int start_cpu, int this_cpu)
+{
+	struct save_area *sa = (void *) 4608 + store_prefix();
+	int cpu, rc;
+
+	for (cpu = start_cpu; cpu < 65536; cpu++) {
+		if (cpu == this_cpu)
+			continue;
+		do {
+			rc = raw_sigp(cpu, sigp_stop_and_store_status);
+		} while (rc == sigp_busy);
+		if (rc != sigp_order_code_accepted)
+			continue;
+		if (sa->pref_reg)
+			return cpu;
+	}
+	return -1;
+}
+
+/*
+ * Initialize CPU ELF notes
+ */
+void setup_regs(void)
+{
+	unsigned long sa = S390_lowcore.prefixreg_save_area + SAVE_AREA_BASE;
+	int cpu, this_cpu, phys_cpu = 0, first = 1;
+
+	this_cpu = stap();
+
+	if (!S390_lowcore.prefixreg_save_area)
+		first = 0;
+	for_each_online_cpu(cpu) {
+		if (first) {
+			add_elf_notes(cpu);
+			first = 0;
+			continue;
+		}
+		phys_cpu = store_status_next(phys_cpu, this_cpu);
+		if (phys_cpu == -1)
+			break;
+		add_elf_notes(cpu);
+		phys_cpu++;
+	}
+	/* Copy dump CPU store status info to absolute zero */
+	memcpy((void *) SAVE_AREA_BASE, (void *) sa, sizeof(struct save_area));
+}
+
+#endif
+
+/*
+ * Start kdump: We expect here that a store status has been done on our CPU
+ */
+static void __do_machine_kdump(void *image)
+{
+#ifdef CONFIG_CRASH_DUMP
+	int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
+
+	__load_psw_mask(PSW_BASE_BITS | PSW_DEFAULT_KEY);
+	setup_regs();
+	start_kdump(1);
+#endif
+}
+
+/*
+ * Check if kdump checksums are valid: We call purgatory with parameter "0"
+ */
+static int kdump_csum_valid(struct kimage *image)
+{
+#ifdef CONFIG_CRASH_DUMP
+	int (*start_kdump)(int) = (void *)image->start;
+	int rc;
+
+	__arch_local_irq_stnsm(0xfb); /* disable DAT */
+	rc = start_kdump(0);
+	__arch_local_irq_stosm(0x04); /* enable DAT */
+	return rc ? 0 : -EINVAL;
+#else
+	return -EINVAL;
+#endif
+}
+
+/*
+ * Give back memory to hypervisor before new kdump is loaded
+ */
+static int machine_kexec_prepare_kdump(void)
+{
+#ifdef CONFIG_CRASH_DUMP
+	if (MACHINE_IS_VM)
+		diag10_range(PFN_DOWN(crashk_res.start),
+			     PFN_DOWN(crashk_res.end - crashk_res.start + 1));
+	return 0;
+#else
+	return -EINVAL;
+#endif
+}
+
 int machine_kexec_prepare(struct kimage *image)
 {
 	void *reboot_code_buffer;
@@ -35,6 +155,9 @@ int machine_kexec_prepare(struct kimage *image)
 	if (ipl_flags & IPL_NSS_VALID)
 		return -ENOSYS;
 
+	if (image->type == KEXEC_TYPE_CRASH)
+		return machine_kexec_prepare_kdump();
+
 	/* We don't support anything but the default image type for now. */
 	if (image->type != KEXEC_TYPE_DEFAULT)
 		return -EINVAL;
@@ -51,27 +174,53 @@ void machine_kexec_cleanup(struct kimage *image)
 {
 }
 
+void arch_crash_save_vmcoreinfo(void)
+{
+	VMCOREINFO_SYMBOL(lowcore_ptr);
+	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
+}
+
 void machine_shutdown(void)
 {
 }
 
-static void __machine_kexec(void *data)
+/*
+ * Do normal kexec
+ */
+static void __do_machine_kexec(void *data)
 {
 	relocate_kernel_t data_mover;
 	struct kimage *image = data;
 
-	pfault_fini();
-	s390_reset_system();
-
 	data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
 
 	/* Call the moving routine */
 	(*data_mover)(&image->head, image->start);
-	for (;;);
 }
 
+/*
+ * Reset system and call either kdump or normal kexec
+ */
+static void __machine_kexec(void *data)
+{
+	struct kimage *image = data;
+
+	pfault_fini();
+	if (image->type == KEXEC_TYPE_CRASH)
+		s390_reset_system(__do_machine_kdump, data);
+	else
+		s390_reset_system(__do_machine_kexec, data);
+	disabled_wait((unsigned long) __builtin_return_address(0));
+}
+
+/*
+ * Do either kdump or normal kexec. In case of kdump we first ask
+ * purgatory, if kdump checksums are valid.
+ */
 void machine_kexec(struct kimage *image)
 {
+	if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
+		return;
 	tracer_disable();
 	smp_send_stop();
 	smp_switch_to_ipl_cpu(__machine_kexec, image);