[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, 208 insertions, 0 deletions

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 7b371c37061d..b5a30412b2e5 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -42,6 +42,9 @@
 #include <linux/reboot.h>
 #include <linux/topology.h>
 #include <linux/ftrace.h>
+#include <linux/kexec.h>
+#include <linux/crash_dump.h>
+#include <linux/memory.h>
 
 #include <asm/ipl.h>
 #include <asm/uaccess.h>
@@ -57,6 +60,7 @@
 #include <asm/ebcdic.h>
 #include <asm/compat.h>
 #include <asm/kvm_virtio.h>
+#include <asm/diag.h>
 
 long psw_kernel_bits	= (PSW_BASE_BITS | PSW_MASK_DAT | PSW_ASC_PRIMARY |
 			   PSW_MASK_MCHECK | PSW_DEFAULT_KEY);
@@ -435,6 +439,9 @@ static void __init setup_resources(void)
 	for (i = 0; i < MEMORY_CHUNKS; i++) {
 		if (!memory_chunk[i].size)
 			continue;
+		if (memory_chunk[i].type == CHUNK_OLDMEM ||
+		    memory_chunk[i].type == CHUNK_CRASHK)
+			continue;
 		res = alloc_bootmem_low(sizeof(*res));
 		res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
 		switch (memory_chunk[i].type) {
@@ -479,6 +486,7 @@ static void __init setup_memory_end(void)
 	unsigned long max_mem;
 	int i;
 
+
 #ifdef CONFIG_ZFCPDUMP
 	if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
 		memory_end = ZFCPDUMP_HSA_SIZE;
@@ -550,6 +558,187 @@ static void __init setup_restart_psw(void)
 	copy_to_absolute_zero(&S390_lowcore.restart_psw, &psw, sizeof(psw));
 }
 
+#ifdef CONFIG_CRASH_DUMP
+
+/*
+ * Find suitable location for crashkernel memory
+ */
+static unsigned long __init find_crash_base(unsigned long crash_size,
+					    char **msg)
+{
+	unsigned long crash_base;
+	struct mem_chunk *chunk;
+	int i;
+
+	if (memory_chunk[0].size < crash_size) {
+		*msg = "first memory chunk must be at least crashkernel size";
+		return 0;
+	}
+	if (is_kdump_kernel() && (crash_size == OLDMEM_SIZE))
+		return OLDMEM_BASE;
+
+	for (i = MEMORY_CHUNKS - 1; i >= 0; i--) {
+		chunk = &memory_chunk[i];
+		if (chunk->size == 0)
+			continue;
+		if (chunk->type != CHUNK_READ_WRITE)
+			continue;
+		if (chunk->size < crash_size)
+			continue;
+		crash_base = (chunk->addr + chunk->size) - crash_size;
+		if (crash_base < crash_size)
+			continue;
+		if (crash_base < ZFCPDUMP_HSA_SIZE_MAX)
+			continue;
+		if (crash_base < (unsigned long) INITRD_START + INITRD_SIZE)
+			continue;
+		return crash_base;
+	}
+	*msg = "no suitable area found";
+	return 0;
+}
+
+/*
+ * Check if crash_base and crash_size is valid
+ */
+static int __init verify_crash_base(unsigned long crash_base,
+				    unsigned long crash_size,
+				    char **msg)
+{
+	struct mem_chunk *chunk;
+	int i;
+
+	/*
+	 * Because we do the swap to zero, we must have at least 'crash_size'
+	 * bytes free space before crash_base
+	 */
+	if (crash_size > crash_base) {
+		*msg = "crashkernel offset must be greater than size";
+		return -EINVAL;
+	}
+
+	/* First memory chunk must be at least crash_size */
+	if (memory_chunk[0].size < crash_size) {
+		*msg = "first memory chunk must be at least crashkernel size";
+		return -EINVAL;
+	}
+	/* Check if we fit into the respective memory chunk */
+	for (i = 0; i < MEMORY_CHUNKS; i++) {
+		chunk = &memory_chunk[i];
+		if (chunk->size == 0)
+			continue;
+		if (crash_base < chunk->addr)
+			continue;
+		if (crash_base >= chunk->addr + chunk->size)
+			continue;
+		/* we have found the memory chunk */
+		if (crash_base + crash_size > chunk->addr + chunk->size) {
+			*msg = "selected memory chunk is too small for "
+				"crashkernel memory";
+			return -EINVAL;
+		}
+		return 0;
+	}
+	*msg = "invalid memory range specified";
+	return -EINVAL;
+}
+
+/*
+ * Reserve kdump memory by creating a memory hole in the mem_chunk array
+ */
+static void __init reserve_kdump_bootmem(unsigned long addr, unsigned long size,
+					 int type)
+{
+
+	create_mem_hole(memory_chunk, addr, size, type);
+}
+
+/*
+ * When kdump is enabled, we have to ensure that no memory from
+ * the area [0 - crashkernel memory size] and
+ * [crashk_res.start - crashk_res.end] is set offline.
+ */
+static int kdump_mem_notifier(struct notifier_block *nb,
+			      unsigned long action, void *data)
+{
+	struct memory_notify *arg = data;
+
+	if (arg->start_pfn < PFN_DOWN(resource_size(&crashk_res)))
+		return NOTIFY_BAD;
+	if (arg->start_pfn > PFN_DOWN(crashk_res.end))
+		return NOTIFY_OK;
+	if (arg->start_pfn + arg->nr_pages - 1 < PFN_DOWN(crashk_res.start))
+		return NOTIFY_OK;
+	return NOTIFY_BAD;
+}
+
+static struct notifier_block kdump_mem_nb = {
+	.notifier_call = kdump_mem_notifier,
+};
+
+#endif
+
+/*
+ * Make sure that oldmem, where the dump is stored, is protected
+ */
+static void reserve_oldmem(void)
+{
+#ifdef CONFIG_CRASH_DUMP
+	if (!OLDMEM_BASE)
+		return;
+
+	reserve_kdump_bootmem(OLDMEM_BASE, OLDMEM_SIZE, CHUNK_OLDMEM);
+	reserve_kdump_bootmem(OLDMEM_SIZE, memory_end - OLDMEM_SIZE,
+			      CHUNK_OLDMEM);
+	if (OLDMEM_BASE + OLDMEM_SIZE == real_memory_size)
+		saved_max_pfn = PFN_DOWN(OLDMEM_BASE) - 1;
+	else
+		saved_max_pfn = PFN_DOWN(real_memory_size) - 1;
+#endif
+}
+
+/*
+ * Reserve memory for kdump kernel to be loaded with kexec
+ */
+static void __init reserve_crashkernel(void)
+{
+#ifdef CONFIG_CRASH_DUMP
+	unsigned long long crash_base, crash_size;
+	char *msg;
+	int rc;
+
+	rc = parse_crashkernel(boot_command_line, memory_end, &crash_size,
+			       &crash_base);
+	if (rc || crash_size == 0)
+		return;
+	crash_base = PAGE_ALIGN(crash_base);
+	crash_size = PAGE_ALIGN(crash_size);
+	if (register_memory_notifier(&kdump_mem_nb))
+		return;
+	if (!crash_base)
+		crash_base = find_crash_base(crash_size, &msg);
+	if (!crash_base) {
+		pr_info("crashkernel reservation failed: %s\n", msg);
+		unregister_memory_notifier(&kdump_mem_nb);
+		return;
+	}
+	if (verify_crash_base(crash_base, crash_size, &msg)) {
+		pr_info("crashkernel reservation failed: %s\n", msg);
+		unregister_memory_notifier(&kdump_mem_nb);
+		return;
+	}
+	if (!OLDMEM_BASE && MACHINE_IS_VM)
+		diag10_range(PFN_DOWN(crash_base), PFN_DOWN(crash_size));
+	crashk_res.start = crash_base;
+	crashk_res.end = crash_base + crash_size - 1;
+	insert_resource(&iomem_resource, &crashk_res);
+	reserve_kdump_bootmem(crash_base, crash_size, CHUNK_READ_WRITE);
+	pr_info("Reserving %lluMB of memory at %lluMB "
+		"for crashkernel (System RAM: %luMB)\n",
+		crash_size >> 20, crash_base >> 20, memory_end >> 20);
+#endif
+}
+
 static void __init
 setup_memory(void)
 {
@@ -580,6 +769,14 @@ setup_memory(void)
 		if (PFN_PHYS(start_pfn) + bmap_size > INITRD_START) {
 			start = PFN_PHYS(start_pfn) + bmap_size + PAGE_SIZE;
 
+#ifdef CONFIG_CRASH_DUMP
+			if (OLDMEM_BASE) {
+				/* Move initrd behind kdump oldmem */
+				if (start + INITRD_SIZE > OLDMEM_BASE &&
+				    start < OLDMEM_BASE + OLDMEM_SIZE)
+					start = OLDMEM_BASE + OLDMEM_SIZE;
+			}
+#endif
 			if (start + INITRD_SIZE > memory_end) {
 				pr_err("initrd extends beyond end of "
 				       "memory (0x%08lx > 0x%08lx) "
@@ -644,6 +841,15 @@ setup_memory(void)
 	reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size,
 			BOOTMEM_DEFAULT);
 
+#ifdef CONFIG_CRASH_DUMP
+	if (crashk_res.start)
+		reserve_bootmem(crashk_res.start,
+				crashk_res.end - crashk_res.start + 1,
+				BOOTMEM_DEFAULT);
+	if (is_kdump_kernel())
+		reserve_bootmem(elfcorehdr_addr - OLDMEM_BASE,
+				PAGE_ALIGN(elfcorehdr_size), BOOTMEM_DEFAULT);
+#endif
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (INITRD_START && INITRD_SIZE) {
 		if (INITRD_START + INITRD_SIZE <= memory_end) {
@@ -812,6 +1018,8 @@ setup_arch(char **cmdline_p)
 	setup_ipl();
 	setup_memory_end();
 	setup_addressing_mode();
+	reserve_oldmem();
+	reserve_crashkernel();
 	setup_memory();
 	setup_resources();
 	setup_restart_psw();