[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();